Yeah, this is true and important. I should specify that some studies have found a direct effect of cold, which I think has to be heart attacks from vasoconstriction, and then probably there are other heart attacks from influenza.
Here in Michigan we get early warnings from the county health departments that shoveling snow is a huge cause of heart attacks, so you’re supposed to take frequent breaks and warm up to avoid the problems of exertion + cold air during heavy breathing + vasoconstriction.
Is it just that people are more likely to get heart attacks while they have the flu, or does having had the flu also increase the risk of heart attacks?
Is there an elevated risk immediately after a serious case of influenza, or does each case of influenza create an incrementally mounting risk of heart disease? The explanation I had previously heard is that inflammation caused by influenza causes progressive and irreparable damage to heart muscle.
I've witnessed the onset of only one hyperthermia fatality, a Czech journalist sent to Florida in mid-July to report on the Apollo 11 moon landing. Despite temperatures approaching 40 C and high humidity ,he dressed in a three piece black woolen suit. He collapsed near the end of a long tour of NASA's sprawling Cape Canaveral space center in a vehicle without air conditioning.
This is minor, but I think this part is backwards:
>Most people don’t clearly say that excess winter deaths are a combination of cold-related (from the flu) and season-related (from cardiovascular) deaths, even though something like this has to be true
Isn't the flu season related and cardiovascular deaths cold related?
I don't really think pointing to influenza or other diseases in Africa does much to explain the data. After all, that just pushes the question back one stage: why is it that these flu deaths are concentrated in the winter? If it's because they are more common when the temperature is lower than wouldn't that also support a causal story? You might try and say it's about the worldwide increase in flu during the winter but that doesn't work as the southern hemisphere has winter when we have summer.
I'm going to suggest a different explanation. Maybe it's all just about extremes of temperature being associated with unusual weather conditions which are more likely to lead to things like crop failures (and all the downstream badness including more wild animals dying leading to more opportunities for death). I have to think a bit more about it but the graphs above estimating MMT make me suspect that this is all mostly seeing some kind of mathematical artifact (e.g. that the more extreme the temperature is on a day the more likely it will be to occur during an unusual weather year).
But why would they spend more time indoors in really hot countries? I mean in the Sahara wouldn't you be outside more frequently during the winter and seek shelter in your shaded home more in the summer?
I mean why is it that people spend more time indoors in the winter? I presume it's because they have greater need for shelter in cold countries and if that was the same mechanism in rich countries then that would suggest a causal mechanism.
> I mean in the Sahara wouldn't you be outside more frequently during the winter and seek shelter in your shaded home more in the summer?
Could this be the mechanism behind the whole thing? The outdoors is a more dangerous place than your own home, and people go out more when the weather is nicer - which means the summer in St Petersburg but the winter in Nairobi.
Flu season is winter everywhere. That seems like it would need an explanation about people being indoors in winter and outdoors in summer, which is only true in half of places. I’ve heard other claims about humidity and air temperature and the longevity of infectious droplets, and claims about travel within the hemisphere during winter. None of it quite adds up.
Humidity is also an unlikely explanation because, obviously, humidity is higher or lower in the winter depending on where you're at.
The only explanation that makes sense to me: The majority of the world lives in cold to temperate climates where there is an actual winter. This leads to a global increase in flu prevalence starting in the winter in the Northern Hemisphere. We "Northerners" then travel around the world and spread it, but it takes time to spread in the warmer climes and so it doesn't hit peak spread until "winter" in the equatorial & global south. A reach I agree
The one point about humidity is that heated air has very low humidity. Air that is at 100% relative humidity at 10 degrees C is at 50% humidity if you heat it to 20 degrees C, and if it is 100% at 5 degrees C then it’s only 30% at 20 degrees C. It doesn’t need to get freezing for the indoor humidity to drop considerably, though it does need to be temperate enough for indoor air to be heated.
The part where you say “this leads to” is the bit that needs explaining. Anyway the thought on humidity is that it’s lower (actual rather than relative) humidity that helps the virus. Humidity, as kenny explains, is lower in colder weather.
What about religious gatherings and holidays being more frequent and larger through the winter months? Notable exception being Ramadan which tends to happen in the summer. Is flu severity simply a matter of the frequency of mass and small gathering occasions increasing the spread?
Ramadan doesn't have a typical season - it is just every twelfth lunar month, and over the course of a decade or so, it rotates through the year and occurs in every season equally.
It definitely seems to me to be a plausible hypothesis that traditional gatherings are the source of the seasonal pattern rather than the weather. In the United States, it seems very plausible that cold/flu season begins in late November and December, and continues for a few weeks afterward, which lines up well with the biggest periods of family gatherings!
But if this is the explanation, then it would suggest that in China and Vietnam, the biggest cold/flu season should be February, and there wouldn't be notable flu activity in December/January. I'm not sure whether that's true.
There are even extreme cases like Saudi-Arabia in which people can't stay outside for a long time in summer. As far as I know, they stay in buildings pretty much all the time during summer.
But the flu season spikes in winter there, like everywhere else. Interestingly, it starts and peaks (Nov-Dec) a bit earlier than e.g. in Europe.
Unrelated, but also interesting from the same source: Fiji (southern hemisphere, close-ish to equator) has a wave either March/April or Jul-Sep, but "usually (only) a single wave per year".
I don't know anything about culture in the Sahara, but I'd bet people gather more when the weather is at its coldest. If you're trying to beat the heat, you'd want to be alone in your shaded home.
Flu isn't all that seasonal in the Sahara. In Africa, influenza is seasonal along the Mediterranean coast and in the southern countries, year-round in the desert and the tropics.
That's quite consistent with cold = indoors = more flu, and so less cold = less flu = less death, supporting the naive interpretation that we want to make the world at least a little bit warmer if we want to minimize death.
But if this logic truly holds, I'd also expect that in places that are hot and rich, warm = indoors because air conditioning = more flu, so that's something to look into. More generally, we have to actually understand why influenza is seasonal in temperate climates before we say that cold's got nothing to do with it and marginal warming would be a net harm.
Your extreme temperature theory doesn't explain why it's seasonal. As I understand it, mortality goes up every year in winter in hot places, and every year in summer in cold places. That doesn't line up with people starving because their crops had a bad year.
Most of them do have some sort of temperature variation, though, even if it doesn't correspond to the summer/winter dichotomy of the areas further from the Equator. Usually in tropical areas the rainy season is cooler because of greater cloud cover. Although it's not a big difference, Singapore does show slightly lower average daily temperatures in Nov-Jan (rainy season), daily mean a bit under 27C, than the rest of the year (dry season), daily mean a bit over 28C.
Note that lack of temperature variation doesn't mean lack of seasonality - the change in humidity presumably has quite significant health consequences.
Many tropical parts of the world have wet seasons and dry seasons. E.g., the monsoon monsoon season arrives around the end of May or early June in India (e.g., the first ascent of Mt. Everest was on May 29, 1953 to make use of warm weather, light winds, and long days but also beat the heavy snows of the peak monsoon) and lasts into the first few days of October. But I don't believe all tropical rainy seasons are on the same schedule.
And I don't know when the starving season would be relative to the wet and dry seasons.
Influenza virus prefers cold temperatures and low humidity. It does not spread well in hot, moist weather even if everyone is inside with the AC blasting. Exactly why this is true is a matter of contention. The common cold doesn't care about heat or humidity.
I believe that David D. Friedman has an explanation for "[w]hy would cold places adapt so hard that they did better than warm places?"
In short, I believe the explanation is that it does not make sense to invest in heat regulating equipment or insulation in temperate places (in his example, New Zealand), because they have high fixed costs. Accordingly, houses in New Zealand are very poorly heat regulated (and, although it does not get extremely cold in New Zealand, the houses are much colder than countries with more extreme temperatures). In contrast, to survive in certain places with more extreme temperatures, it makes sense to incur the fixed costs. Once those costs have been incurred (e.g., for insulation), the average cost of achieving the optimum temperature year round is low.
I seem to recall that David D Friedman had this written up somewhere, but I can no longer find it. Since I understand David reads this substack, hopefully he will be able to expand further (and apologies in advance for any incorrect summary).
Came here to make this same point. If a place expects a winter low of 70, but a cold snap hits and suddenly it's 30, people are going to freeze to death by the thousands. Meanwhile, if you were expecting -40 and it caters to -80, your heating bill increases slightly and you get to tell your grandkids about the great cold snap of '21.
I wouldn't expect heat deaths to follow the same pattern, though: 50 to 90 sounds harmless, while 110 to 150 sounds disastrous.
There happened to be something like that in Texas back in February. We normally have winters in the 20s to 30s F at the coldest, but all of a sudden had snow as far south as Austin and nights below 0 F. Our power grid, for various reasons, wasn't prepared for such a cold freeze, and left a lot of people (my family included) without power for at least a couple days. I don't know off the top of my head how many actually wound up dying because of it, but lots of water pipes burst and the whole fiasco cost a lot to recover from
Don't forget that not all of those people were on the Texas grid that went out. Some were on the Louisiana grid, etc. It is frustratingly hard to tease out.
Unlike Texas last February, northern Midwestern cities like Chicago routinely function at below zero temperatures, but Chicago's power grid was knocked around badly when the heat hit 106 in 1995, a routine temperature in inland Texas.
> Unplanned fab shutdowns can have long-lasting impacts; for instance, a thirty-minute power shutdown in 2018 at a Samsung fab destroyed 3% of the global supply of NAND.
(not researched how significant it turned out to be in the end but definitely not helped, it is typical that power outage means that everything being produced becomes worthless - and production time may reach month, so power outage can mean losing months of production)
Yeah, I'm aware of aluminium smelteries having their own dams for hydropower, and I don't think that they would suffer nearly as much from power shortages !
I work in a die fab in the US. We do have generators, as well as various mitigation strategies.
These only work, however, if we are in the position where they can be immediately put into play - which basically means they're already turned on when the power goes out. (We also do things like avoid running too much product when it is extremely windy outside, precisely in order to minimize how much damage can happen from a power outage).
You can't just turn on your generation capacity *in response* to the power outage - it actually has to be on *beforehand*. Any sort of power interruption causes some of the particularly power hungry machines to be powered off briefly, which is a Problem because when they come back on, they can't just immediately resume what they're doing. I'm not sure if this is for safety reasons (you don't want your machine to immediately start ramping up to doing whatever dangerous thing caused an estop to be pressed, except it wasn't an estop, it was the actual power going out, but as far as the machine was concerned, the power was cut) or if it is just poor programming, but it is what it is.
Some of it is also just the fact that these processes are so precise, so any small deviation will completely ruin everything because it is off by a micron and you're done. Even less sensitive processes - like singulation of die - can be messed up a bit by a power outage.
Also also, if the power goes out, oftentimes the power generation is for safety rather than saving the product - that is to say, they want to make sure that the LN tanks don't have a problem, that all the acid stays where it is supposed to, that nothing that can't cool off cools off and nothing that can't heat up heats up, making sure that your cleanroom fans are keeping your cleanroom from getting contaminated (as cleanroom contamination can ruin *everything*), etc.
Knowing stuff from my die fab, it takes like a month to process a wafer from start to finish. So 1/12th of the product for a year (about 8%) is going to be being in process at any given time. Some of that 3% that is ruined going to be from the product being wrecked by being in a sensitive process, and some of it will be because of delays caused by the power being out.
An unplanned half-hour power outage has much larger issues than just "Oh it is out for half an hour"; a lot of equipment needs to be reinitialized and tested after a power outage.
It is also worth noting that some stuff can't sit at certain steps for too long, so anything that is sitting around can potentially "spoil" so to speak.
Oof - that's way more complicated than the data center my cube is on top of, where they can run on battery while the (large and many) generators spin up. (The battery rooms are Not Small, either.)
I have a friend who worked through the storm at Samsung. They had to scrap EVERYTHING, to the tune of billions of dollars. It took a few weeks to get things running again too, because pipes broke, equipment needed to be replaced, and supplies like chemicals needed to be replaced.
Single data point, but up in Canada air conditioning is fairly uncommon, because swelteringly hot summers (to the tune of 110+F) are equally uncommon. It could be the same effect: a heat wave hits and you have no way to cope with the excess heat, unlike in places where you expect that sort of thing regularly.
Be careful of proving too much. It's a good formalization of the idea "assuming all temperature adjustment is heating, equilibrium room temperature is independent of exterior temperature with the dependent variables of heating and insulation costs trading off directly". But extrapolating from there to what's covered in Scott's article deviates from that assumption: the asymmetry between heating and cooling costs means the equilibrium insulation solution will *very much* depend on exterior temperature in any location that ever needs to run an A/C.
(Does that asymmetry explain why MMT is so different in different in different countries? In short - no. There's still a few factors missing inexplicable by mean temperature alone.)
One data point - we ran an SF con in the winter (in Sweden) and had an English GoH, and one of the things he said was that he liked that he didn't have to feel as cold here.
I suspect that England is still pretty much in the mindset of "put another jumper on" rather than making the house insulated enough to be warm all through. The relatively recent switch away from coal heating probably meant that sealing the houses better was not a good idea (coal was pretty dusty).
Also: England is cool and wet during the winter, as opposed to Sweden which is much colder and relatively dry. Which may be a confounder to relating flu deaths to temperature alone - is there a humidity-related factor there as well?
I believe that cold, dry air indoors is the most favorable conditions for flu to spread. With high humidity, droplets gain weight and fall while with low humidity they turn into aerosols.
Oh, if we are talking about two separate spouts then it is so uncommon in the U.S. that it didn't even occur to me. Good call if that's what we're talking about (I also have never seen it).
Separate spouts. I'm an American living in the UK. The plumbing here is ridiculous.
(Of course, it's this way for valid historical reasons, something to do with ensuring stale water doesn't backflow into the drinking water supply, if I remember right. Tom Scott did a video explaining it. It's still ridiculous.)
> Once those costs have been incurred (e.g., for insulation), the average cost of achieving the optimum temperature year round is low.
The annual cost of heating is still higher in cold places, but the marginal cost of heating the house to be (say) 1°C warmer is lower. So if people in cold and warm places have similar heat preferences and similar incomes, the temperature at which people keep (i.e. the temperature at which more heat is no longer worth the cost on the margin) is lower. (This was David's argument, approximately.)
Having lived in Italy with roommates, I can confirm. Homes often have thin walls, single-layer window panes, and frigging metal window frames. And I find the home temperatures they have in the winter very low. Whereas in Hungary, the norm is double-layer windows, and wooden or hollow plastic window frames.
Same experience between Moscow and Tokyo. Tokyo: flimsy walls, single-pane windows, heating often with just an AC on the wall. Moscow: thick walls, double-glazed windows practically everywhere (and double panes MINIMUM if it's and older building), district heating.
Another effect of this: you can bum it out in Tokyo, and there are tent camps filled with homeless under underpasses etc. A sudden cold snap might kill these folks. In Moscow it's impossible to live on the streets so nobody dies from -35C (even if it lasts for weeks). However, hot weather will kill some people without access to an AC, predominantly old.
You see something like this effect in the US. Often the electric systems that see their peak in the Winter tend to be in Florida and Texas. This is because in those places it does not make sense to invest in a separate natural gas heating system.
Instead they use heat pumps that are essentially air conditioners in reverse. But they only are effective on moderately but not extremely cold days. On extremely cold days those systems need to use backup resistance electric heating which is far less efficient. But overall it makes economic sense not to invest in a separate system given those regions experience so few cold days,
I was under the impression that reverse cycle air conditioners were about 4 times as efficient as converting electricity directly into heat (though I guess that assumes only a modest temperature differential); I'd assume house design plays a much larger role than the choice of heating system
It is much more efficient but it only works down to a certain temperature. After it get too cold the heat pump is not effective. So most heat pumps have a back up resistance system that can add additional heating on really cold days. Its because it is less efficient that really cold days in warm places tax the electric grid.
God knows I've been colder in the winter in my poorly-insulated Bay Area house than I ever was indoors in Chicago, where they understand about insulation and adequate heating. We used to complain about the draftiness of our Bay Area house and my mother would say, "Well, at least it's ventilating out all the radon." Thanks, Ma. Now where's the afghan?
After reading this post I immediately ctrl + F:d "David Friedman" to look for this comment. I'd read Friedman's piece on temperature regulation in Chicago homes vs California homes something like 10 years ago and my mind went there immediately. Strange how memories work.
Wait, no, isn't there a *really* simply explanation here. Generate some random data. It will always have some minimum mortality associated temperature. If you then call the increases in death relative to that MMT that occur at higher temperatures heat related and those at lower temperatures cold related you'll find alot of heat and cold related deaths.
I agree this doesn't quite explain the asymmetry between hot and cold temperatures but I'm going to guess it's something simple about the fact that plants are grown during the hottest part of the year leaving the coldest part of the year more time to do things like fight wars or when shortages are more likely to push people into lower immune activity or making more dangerous choices.
I do see a number of S shaped ones as well but many do have this pattern I grant. But couldn't this just be regression to the mean? If you only have a very few days with very high or low temperature that will tend to be yield a more extreme average than if you average a huge number of days with a common temperature.
Also, they don't really say what the actual graphs represent. Based on what they are doing it sounds like it's something they predict by fitting a 21 day lagged thing with B-splines....wouldn't surprise me if this introduced some statistical artifacts.
The regression to the mean thing might predict extreme death rates at extreme temperatures, but it wouldn't predict that the anomaly would always be an increase, which is what is observed here.
I definitely feel there's room for it to be some correlated third variable, like eg storms, but the plots don't seem consistent with statistical noise
Scratch that, I hadn't read your other comments - I thought the include plots were death rate on days with that temperature, and even if their extrapolations wrt global warming are based on weird models the status quo would still require explanation. If the curves excerpted here are the heavily processed model rather than the raw data, though, all bets are off
I'm having trouble going through their math because, even as a mathematician, it seems annoyingly complicated. I will point to this fact which *might* be how they are drawing their curves:
"Specifically, we modelled the exposure-response curve with a quadratic B-spline with three internal knots placed at the 10th, 75th, and 90th percentiles "
If so, a quadratic B-spline is just a bunch of quadratics slapped together piecewise and, unsurprisingly, quadratics tend to go off to plus or minus infinity.
But these graphs seem to be more about the RR which they claim to derive from semi-Poission regression. But there are just so many ways you could end up introducing this kind of thing as an artifact in such a complex analysis I'm still betting on artifact.
I haven't thought this through, but why is there a knot at the 75th percentile? That seems highly suspect in conjunction with the "MMT is always near 80th percentile" thing...
So I went in and figured out how they are doing the lag time and it's even more worrying in terms of creating artifacts.
What they do is assume that an individuals overall risk of death on a given day is given by integrating some non-linear function of temperature over the past 21 days ( they point reader to this cite https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4098103/ ). But they don't tell us what non-linear function they assume but whatever they do the problem is that it's very likely to yield really weird predictions about the relative risk of the most extreme temprature days. When they fit the model they will be trying to minimize some kind of error and the fact that there are few of the most extreme temperature days will tend to mean that they get pushed to the most extreme values to balance out random fluctuations.
I'm not someone who runs regressions all the time so maybe I'm missing something but it seems like there is every reason to think that (in some way or another) the fact that there are few of the most extreme temperature days causes those days to tend toward extreme values.
I'm going to see if they will send me the R code and try feeding in some random values if I have time. If not someone else should try.
Another thing that could be causing artifacts here is the relative risk scale they are using. Towards the middle of the temperature distribution, there is probably enough mortality data so that the RR estimates don't deviate much from 1. At the extremes of the temperature distributions there will be less mortality data, and random fluctuations will generate more outliers. If there is no effect of temperature on mortality, you would expect equally many outliers with RR of 0.5 and with RR of 2. However, the mean of these outliers would be greater than 1. So I think it's possible that on the RR scale, the estimates of the mean can be biased upwards in regions with little data. Things might be looking differently on a log(RR) or log(odds ratio) scale.
I'm just speculating here, I didn't actually take a close look at the methods.
I have little to add aside from linking to my favorite flu-related paper, on the 9 conundrums of influenza
" (1) Why is influenza both seasonal and ubiquitous and where is the virus between epidemics? (2) Why are the epidemics so explosive?
(3) Why do they end so abruptly?
(4) What explains the frequent coincidental timing of epidemics in countries of similar latitude? (5) Why is the serial interval obscure?
(6) Why is the secondary attack rate so low?
(7) Why did epidemics in previous ages spread so rapidly, despite the lack of modern transport? (8) Why does experimental inoculation of seronegative humans fail to cause illness in all the volunteers?
(9) Why has influenza mortality of the aged not declined as their vaccination rates increased? "
The authors hypothesize Vitamin D levels and "Good infectors". Whole paper is worth a read though.
Given the summer RSV season we just went through I'm unfortunately somewhat pessimistic...I think travel bans and border closures particularly in southeast Asia plus a hefty dose of viral competition played a big part in the flu being so minor, and if people are expecting some cloth masks to get rid of flu season this year I think they are going to be disappointed. But I could be wrong! Time will tell.
Yeah, I'm not the expert but my friend the pediatric pulmonologist said about a month ago that even COVID aside, their (hospital) floor looked like a normal February.
This paper is fantastic, thanks. This really does help to explain the seasonality of the flu, and explicitly helps to explain why i.e. African populations might be more sensitive to seasonal variations in temperature when it comes to the flu.
It frustrates me a little that the messaging around covid at the moment is still "We don't know if it's seasonal", when it's been behaving exactly like a seasonal virus all this time.
I worry that the Northern Hemisphere is about to discover that even with a heavily vaccinated population, keeping Delta (or maybe Delta+) covid under control in the winter is a much harder job than keeping it under control in the summer.
I agree this is a really good bet, but I'm frustrated that we still don't know enough about seasonal viruses to even know what to look for (other than the obvious fact that it gets worse in one season).
Don't most viruses have reservoir species that they live in, in addition to humans? Could the seasonality of human infections have to do with either the life cycle of the virus in the reservoir species or the times of year the reservoir species interacts most often with us? I should note that I know basically nothing about viruses above a layman's level; I apologize if this has already been firmly refuted somewhere.
I'd imagine that animal-to-human transmissions are an extremely small fraction of all transmissions of viruses like the flu or colds (almost all transmissions being human-to-human), and thus animal reservoirs are unlikely to have a significant effect.
A big unknown is how well immunity (from previous infection or vaccination) will reduce the spread this winter. Jones, Stone, and Sulaeman [1] estimate that about 83% of Americans had antibodies to SARS-CoV-2 in May 2021. Presumably an even higher percentage will have antibodies by the start of winter. But on the other hand, there is evidence of waning immunity from the 2-dose Pfizer/BioNTech schedule [2]. And probably most of the general population won't have received a booster before the start of winter, especially given the FDA's inexcusable tardiness to approve boosters.
The FDA is slow to approve boosters for good reasons, it turns out. It's not tardiness. Arguably, they are actually starting to "wake up" from COVID-dreamland, and ask the sorts of hard questions regulators are meant to ask. For example, here are some of the issues with the Moderna booster trial:
1. No evidence of improvement in any actual clinical outcome. It doesn't stop infection, not even for a brief time: there was a 22% infection rate amongst trial participants. The presented argument for why the boosters "work" is that they trigger the production of antibodies. Yet medicines are supposed to achieve clinical outcomes, not merely change body chemistry. Even given this ridiculous success criteria, the pre-registered criteria for the trial was in fact NOT met. Moderna appear to have come up with an alternative criteria
2. Very small sample sizes in the trial.
3. Very unbalanced samples e.g. 60% of participants were women, virtually all were white, lower rate of obesity than normal, mean age was 53! They should be trialling this in the elderly but like before, generally aren't focused on those people.
4. They excluded participants with heart conditions, diabetes, etc, i.e. those who are perhaps most at risk from side effects yet who will certainly be told to take it if approved.
6. It's difficult to compare infection rates between vaccine and control arms because of how they present the data (the two arms weren't really identical), and the FDA was unable to independently confirm their analysis.
7. At the same dosage as before 28% of recipients needed medical attention! So they halved the dose, yet, even after that, side effect profile remains roughly the same as the prior round (or so they claim). More than half of people got headaches or fatigue, half got muscle or joint aches. It's not a pleasant process to get boosted.
Given that the boosters (a) don't improve anything anyone might actually care about and (b) are painful and unpleasant to take, I give it about 4 months before they're being mandated by governments and anyone who refuses is being demonized. TRUST THE SCIENCE!
Whatever the fda is doing it’s not what you want. They didn’t complain about the data - they just took months to meet and then approved it when they did.
I'm not sure. That doesn't seem to be mentioned by the articles I read about it. Note that reduced hospitalizations wasn't something the original non-booster trials were looking for and wasn't a claimed benefit of the vaccines before effectiveness against infection collapsed. The claims vaccines reduce hospitalization are all based on seeing how many vaccinated people turn up in hospitals, I think. But there's a confounder there: everyone is being told that if you're vaccinated, you won't need to go to hospital, and a lot of hospitalization is driven by people choosing to go there.
I don't know if any study is able to control for that.
I don’t think “exactly like a seasonal virus” is right. The UK’s two highest case spikes so far were early January and mid-July. Last year we had a very mild September, this year cases have been quite high. There are a huge number of confounders (particularly the governmental restrictions) that make it hard to say what the behavior would be seasonally all things being equal. There does appear to be some seasonality to the data to my eye I don’t think it’s open and shut by any means.
My guess is it might be periodic but not exactly 'seasonal' in the sense of 'tied to a season'. Eyeballing the graph of new cases in our area, the waves have peaks/centers around 18 weeks apart (give or take a couple weeks), or about four and a half months.
Are there other viruses that have both a summer and winter season in the south, and just a winter season in the north? That’s the best guess on this right now, but with a total of two summers and one winter it’s hard to be confident.
As far as I understand it, the expectation of increased mortality at higher temperatures boils down to (no pun intended) the shape of the mortality curve at most cities. The rate of increase of mortality below the optimal temperature is gradual, while the rate of increase of mortality above the optimal temperature is steep. Assuming that the mortality vs temperature curve doesn't change over time (a big if), a given temperature increase causes a large increase in the heat-related mortality and a smaller decrease in the cold-related mortality.
Additionally (and frankly, more problematically), it is causing significant disability in a significant fraction of victims. Roughly 1 in 10 COVID patients who had mild cases (i.e. no need for hospitalization) suffer from long term effects.
I have a friend who now suffers from asthma and chronic fatigue due to COVID. He never got super sick but he was coughing heavily for months and has to use inhalers now, and he feels exhausted after working for just four or five hours and often has trouble doing fun things because he's so tired.
This is honestly far worse than it killing elderly people, as it will have much larger negative societal ramifications.
In winter people have fewer fresh fruits and vegetables to eat (especially outside the first world). They also get less vitamin D from sunlight. Worse nutritional status in the population could weaken immune systems and slightly increase the r-factor of any virus. Plus cold helps the virus survive longer outside the body, and incentivizes people to gather indoors. The r-factor of the flu hovers near 1, so those small changes can make it go supercritical or subcritical seasonally. That's my best guess as to why the flu is seasonal.
But in general warmer areas have a higher disease burden due to vectors that can't thrive in colder climates. Warming will likely expand the territory of malaria, and I don't know if anyone is factoring that into their calculation of warming deaths. But maybe that will be moot if someone invents a good vaccine or a clever way to kill the insect vector. There's too much unpredictable human action between the warming and the final consequences to have high confidence in any number of deaths.
I'm not sure warming will expand the territory of malaria. Malaria used to be common in southern Europe and southern U.S.; it isn't anymore because of modern anti-mosquito efforts. It's become a mainly tropical disease because the tropics are poor.
I suppose there might be some place in Asia, currently protected by its climate, that won't be able to afford anti-mosquito measures.
It's maybe worth considering that "winter" in sub-Saharan Africa (at least the part of West Africa which I am most familiar with, which admittedly does not actually have such high cold-related deaths) is more commonly referred to as "the dry season". It is definitely colder, and many people do have very poorly insulated houses; i.e. not even single-glass window panes, so that nighttime temperatures of 12°C can actually be dangerous for vulnerable people. However, the lack of food, and perhaps also poorer access to safe water and sanitation, may be bigger factors. If this is about food though, then things should get even worse in the "spring", i.e. when it is warmer and the rains have started but before any of the new crops can be harvested.
On the flip side, in the tropics the number of hours of sun is basically constant throughout the year so reduced levels of vitamin D are not a plausible explanation for increased flu incidence unless it is entirely due to people not going outside. Also, the dry season should have lower malaria risk, so whatever effect is causing excess winter mortality needs to be big enough to outweigh malaria.
Not sure if the dry season would have lower malaria risk. I think it would depend on just how much rain falls in the wet season. Since the mosquitos breed in standing water, if the rain causes everything to overflow you won't get more mosquitos until it dries up a little.
What about lower respiratory damage from indoor fires? I just read an article a couple of days ago saying that the high price of canned gas (propane-butane, I guess) is forcing many West African households back onto biomass fires for cooking--and, presumably, space heating or radiant heat.
Carbon monoxide in the one case, carbon monoxide and noxious particulates in the other. I don't know for how long gas cookers have been widespread, but if this matters the uptake pattern should correlate inversely with winter mortality in WA.
Hi will, just to pick on a small part of your argument. I don't think Vitamin D has been shown to be causally important in any disease not related to bone health. While there have been a lot of diseases that seem to be associated with Vitamin D deficiency, subsequent attempts to rigorously study if supplementing Vitamin D levels would help have all been disappointing (again outside of bone health) and not found an effect (please tell me if I'm wrong!).
I think a big reason for this is that people with low Vitamin D levels are generally pretty different from people with high vitamin D levels! People with low Vitamin D levels generally don't go outside and people with higher Vitamin D levels do. For literally any disease (maybe with the exception of skin cancer, which more on that in a second), if you asked, which group of people will have less of it/have better outcomes, those who go outside, or those who don't, you'd likely say the group who goes outside more is healthier.
In skin cancer, high vitamin D levels are associated with higher incidence! Does vitamin D cause skin cancer? Of course not! This association is confounded by exposure to sun. Likewise the relationship between vitamin D and COPD, Asthma, heart disease, cancer, and any of a number of other disease is likely confounded by going outside, which is a proxy for how active/social/otherwise robust someone is.
It turns our that exposure to the sun isn't just about vitamin D. Human have precursors under the skin for nitric acid, and they're activated by sunlight. (I don't know about sun lamps.)
Nitric acid helps regulate blood pressure.
Just for fun, it turns out that you can't find out about this by studying mice. Mice don't have the precursors under their skin, probably because they're covered with fur and prefer only going out around twilight and dawn.
Not my original source which was from a humorous British scientist (doctor?) who spent some time in Australia and was getting teased about the high rates of cardiovascular disease in his home.
Cold weather probably causes people to go outside less and be less active, which is unhealthy. Vitamin D may or may not be in that causal chain, but either way we can say that cold weather makes people less healthy and thus more vulnerable to flu.
The above are all autoimmune conditions. Death from respiratory viruses can be sort of similar, in that the immune system causes so much inflammation in the lungs that it kills you. But so far the results of vitamin D on covid are sorta mixed and unclear.
-Presumably one way to die while hunting in Greenland involves ice not being as solid as you thought, which is more likely if it's warmer? Do Tibet and the Andes experience something similar with more avalanches or rock/mudslides?
-One group of people who are particularly vulnerable to the cold are the homeless. Is there a relation between homeless population and cold-weather deaths, and is this affected by things like emergency shelters that only open in unusually cold weather?
I have read that Inuit are falling through the ice a lot more than they used to. They figured out how to recognize thin ice centuries ago, but today's thin ice doesn't always look like it should.
I am fairly certain only hardcore traditional-minded Inuits still hunt on the ice, or hunt at all. It has become like Sami reindeering in Scandinavia - only a fraction of the Sami have anything to do with it.
Most Inuits live in cities, like most Sami do. (I would be surprised if this was different in, say, Canada, or everywhere really.)
I find the human ability to adapt to different temperatures fascinating, and I'm not sure I understand it well enough to dismiss the idea that people are dying at 60 degrees F out of hand.
My brothers and I all grew up in a temperate, almost Mediterranean environment: rare to get as hot as 100, rare to get as cold as 25. As an adult I moved to a place where the typical winter temperature is around 0, and in summer it doesn't reach 90. He moved to Mexico.
He visited me once in summer: it was 75-80 degrees the whole time he was here, and he spent the whole trip in a long sleeve jacket with a puffy vest on top. Because he was cold! It certainly wasn't a put on, his internal thermometer had just shifted upwards while mine had shifted down. A couple years ago we had a heat wave where it hit 88 degrees for a week: we were all miserable with the heat, even though I would have been fine with 88 before I moved up here. My younger brother is planning on moving to Sudan and has visited there before, in a region where the typical summer temperature is in the high 90s, low 100s. While he was living in Texas someone who had lived in South Sudan for a few years came to visit and talk to him about moving to Sudan, and that guy also wore a long sleeve jacket and puffy vest his whole visit. In Texas. In summer. He was genuinely cold.
I don't know how the body does it, but if someone can be genuinely cold in Texas in summer because they're used to hotter, isn't it possible that person might die of cold if it hits 50 degrees?
Assuming the people involved are naked overnight: 50* would kill a Eskimo. 70* would kill you. 90* won't kill anyone. Subjective temperatures are hilarious, but there are hard limits here.
Based on my Boy Scout experience, being cold enough to be miserable doesn't necessarily mean you're in danger, even when you're sleeping. (Of course none of us were old or vulnerable.)
Weren't your and your brother's temperature preferences different before you moved? Couldn't that have to do something with why you moved to a colder place, and him to a warmer one, in the first place?
As far as I could tell growing up we had the same temperature preferences: he loves Mexico because there isn't any pollen in the air, unlike where we grew up.
Populations with generations of adjusting to hard labor in extreme heat, say Sub Sahara Africa, or extreme cold, say Greenland, might have trouble shifting gears in a sudden cold snap or heat wave.
I moved from Georgia to Ohio, and it took a lot longer than 5-7 days to adjust. My first winter here felt colder than later winters, even though it was actually milder.
I've never done any serious mountain climbing but I understand that teams set up a cold base-camp to acclimate themselves, and 5-7 days sounds about right for what they do.
And these are relatively young, prepared, nourished, healthy or even athletic people. If I was old, unprepared, unhealthy, and more 'warped by toil' than 'athletic', I'd be more likely to just kick the bucket.
It is possible to die of exposure at surprisingly high temperatures, adaptation or no - the most common temperatures at which people die of exposure are in the 30s-50s F, and it's possible to die of exposure even in temps as high as the 60s F. If you are wet and it's windy and 65F, hypothermia is a real risk.
It reminds me of an Ethopian girl I knew in the 80s who was on a temporary assignment to my place of work. In May we had some warm sunny days so of course we Irish were all wandering around in our shirts enjoying the unusual heat. But poor Mobete was still shivering in her wooly jumper!
After living in Phoenix for years, my comfort range is 82F to 113F (28C to 45C), at least given desert humidity. Below that range I'll put on a jacket; below 68F (20C) I have difficulty coping even with a thick jacket. In the article, Scott expressed shock at the idea of someone dying from the cold at 54F (12C), which to me just sounds like he's lived a long time in the Bay Area and Michigan and other places where that's a normal temperature.
Yeah, that's exactly the sort of thing I'm talking about. After living much closer to the arctic circle, 54F is short sleeves weather and 80+F is "It's too hot! I'm sweltering!" What I really want to know is how much of our ability to adapt to temperature is physical vs mental. If it's significantly physical than it's reasonable for 54 degrees to be fine for me and deadly for others.
No consideration of the possibility that all this weirdness has something to do with genetic differences between populations? Africans are adapted to one climate, Swedes another. You can speculate all day on what that means, but all we know is that genetics is probably conflating all of this somehow and we can’t know anything until we account for that.
I was wondering about this with regards to the cardiovascular deaths. If one population has mostly enzymes or vein structures or other factors that are tuned to work best in a particular temperature, it's plausible that going below that temperature could result in excess mortality for that population, even if it's not considered dangerous for the "typical" human. But then I also wondered, isn't temperature inside the body extremely tightly controlled? Just how consistent is internal body temperature a) in different environments and b) in different populations? c) the outer parts of the body near the skin vs say, the heart and lungs?
Just to indulge in one bit of speculation, much more of the world population will be of black African descent in the coming decades, whether they stay home or end up settling abroad. Therefore, this tilts things in the direction of a warmer world in which more people are adapted to the warmth, making global warming seem less bad.
I originally considered that Greenlanders, Tibetans, and Andean Indians are really the three groups that have the most evidence for cold-related adaptations (there are other people in cold areas, eg Canadians, but they're colonists). But it was hard to go from there to "dying of minimal amounts of heat", and again, it seems weird that they would over-adapt rather than correctly-adapt.
I think if there was some sort of evolved ideal temperature x actual temperature interaction, we would see more weird stuff in eg the US, where lots of people who evolved for eg England are stuck in eg Florida. But I think the US has a pretty similar pattern to Europe.
> But it was hard to go from there to "dying of minimal amounts of heat", and again, it seems weird that they would over-adapt rather than correctly-adapt.
This is one of those things where I wonder if they have adapted correctly to the 90% case, thus adding risk to the 10% case. In other words, at-risk people are comfortably adapted 90% of the time and under temperature-related physical stress 10% of the time, and that 10% of the time is when a disproportionate number of them die.
America used to have strong seasonal mortality patterns due to infectious diseases. In the South, whites died more in the summer, in the North, blacks died more in the winter. Tropical vs. respiratory disease rates had a lot to do with the demographics of the Union vs. Confederacy and the profitability of slave labor.
There are some observable differences between populations in terms of temperature regulation, such as distribution and structure of body fat. This seems (confidence: likely but not settled fact) to be both a function of genetics and environmental adaptation.
Population of large parts of America is from ancestors adapted to very different climates, same with Australia and New Zealand, and to a lesser extent everywhere with large scale migration. So unless there was extremely significant adaptation in the last couple hundred years it doesn't seem plausible
Aren't suicides seasonal? A quick search gives me Wikipedia saying they're much higher in spring and summer, though it sounds like it's about the season and not the temperature. Is this effect too small to be important?
The seasonality in the New York City chart is striking. It is always peaking around the end of year. I'm thinking what if the real cause is lack of daylight and sunshine and the cold temperature is just a correlation. It would make sense. People are miserable when it is always dark, they have poor imunity because of insufficient exercise insufficient vitamin D and bad mood, it could be good explanation for excess deaths. After all you are a psychiatrist, you know better.
End of year also is a time when people consider the state of their life. The obvious place to look to rule that out or in is the Southern Hemisphere where end of year is in summer.
As someone who's been depressed for ages, I'll say that I generally get worse in winter.
A quick bit of googling found that chilblains can show up at temperatures up to 16° C. No one is dying of hypothermia at that temperature, but that doesn't mean health can't be affected, especially if you don't have access to a source of artificial heat.
My completely speculative take of the scatter plot you you show is that countries to the top-right, i.e. high-temperature high-death countries, look like they could have more homelessness than the ones on the bottom-left. Perhaps it is homeless and almost homelessness that is explaining part of the relation, but I doubt it is much.
I don't understand how the MMT chart for NYC (showing the highest mortality at high temperatures) fits with the NYT deaths-over-time chart (showing the most deaths in the winter). I didn't take the MMT charts to be some sort of adjusted-for-season death rate, it's just death rate vs temperature, right?
Temperatures near the high have the lowest mortality but temperatures at the high have the highest, while all temperatures near or at the low have elevated mortality.
I happen to suspect the whole thing is a weird statistical artifact of their analysis, but it could be consistent if all winter has elevated death, while most of summer is low death apart from a few spike days.
It appears that the answer to the question "will global warming cause fewer people to die from the cold?" is "no: it will in fact cause _more_ people to die from the cold".
This depends on whether the "death vs. temperature" distribution stays fixed as the distribution of temperatures moves up, but that naively seems unlikely to me given that "death vs. temperature" is already so highly variable across geography.
Also relevant: did the Grateful Dead prophesy in "New Speedway Boogie" that the end of the world would come with cold-related deaths in high temperatures?
Jerry and the boys did a lot of their American Beauty and Working Mans Dead stuff at The Guthrie Theater in Mpls in October 1970.
I saw the second show. Not sure if they did NSB. Mainly remember them bringing down the house with a 20 minute cover of Dancing in the Streets. Damn. What a show.
More than half of all Americans die in an institutional setting: hospital, nursing home, or inpatient hospice. All home + road + other deaths combined are less than 50%. The temperature inside a hospital has very little correlation with outdoors temperature, yet we see this incredibly consistent temperature-mortality correlation throughout multiple US and world cities.
If there was a breakdown of temperature-mortality curves based on place of death, we'd have a fairly good idea of whether it has anything to do with temperature at all.
If the correlation was truly a direct causal effect (unusual temperature -> death) then we would see an extremely strong correlation for outdoors deaths, a moderate correlation for home deaths, and very little correlation for hospital deaths. On the other hand, if the correlation mostly reflects seasonal variations in infectious disease, risk taking behavior, diet, etc. then we would see very similar curves regardless of place of death, or even stronger mortality curves in hospice and nursing home settings where the populations have the highest susceptibility to infection.
If someone gets a fatal case of something temperature-related outdoors, but survives long enough to make it to the hospital, would that count as a hospital death?
Yes, so the "hospital" numbers wouldn't be entirely reflective of place of illness.
On the other hand, folks living in nursing homes or inpatient hospice generally get VERY few outdoors hours, and none when the weather is bad. So the temperature/death correlation for NH/Hospice place of death should reflect "not actually temperature causality".
I'm actually not entirely sure that's accurate. Even if a nursing home is perfectly temperature controlled (which I'm uncertain about - it has been a while since I've been in one but I don't recall my relatives feeling that way) there are second order effects at play here in cold weather vs. warm weather:
* Fewer family / friends visits as the weather makes it challenging = less social interaction which is significantly important / highly correlated with mortality
* Less outside time in the winter = less physical activity & less Vitamin D (even a small amount makes a big difference)
* More absenteeism & tardiness in the nursing staff = more unintended mistakes with medicines & care and less familiarity with specific needs of the patients
I could see all of those playing a major role - and honestly probably extend outside of nursing home environments in cold weather and have similar negative impacts across the board.
If someone dies of influenza in a hospital or nursing home, then either an influenza virus spontaneously generated inside that institution, or someone managed to get the flu outside the institution and bring it in with them. So people will mostly die of influenza in hospitals, etc, at about the time people are getting sick from the flu outside them.
Here's a well-documented example of heat-related excess deaths: Worst heatwave of my 18 years in Chicago was five days in July 1995, where the temperature peaked at 106 and humidity was very high. The heat caused partial power outages so air conditioners were off at times and even iceboxes lost their ice.
Out of a population between 2.5 and 3.0 million, an estimated 739 more Chicagoans died that week than was normal. From Wikipedia:
"Eric Klinenberg, author of the 2002 book Heat Wave: A Social Autopsy of Disaster in Chicago, has noted that the map of heat-related deaths in Chicago mirrors the map of poverty.[2][7] Most of the heat wave victims were the elderly poor living in the heart of the city, who either had no working air conditioning or could not afford to turn it on. Many older citizens were also hesitant to open windows and doors at night for fear of crime. Elderly women, who may have been more socially engaged, were less vulnerable than elderly men. By contrast, during the heat waves of the 1930s, many residents slept outside in the parks or along the shore of Lake Michigan."
The city government didn't do a good job of responding with cooling shelters or public service messages to check on your aged relatives, although after the disaster they improved their response notably in subsequent heat waves.
In France in the 2003 heatwave 14,000 people died. I've heard that it is particularly the elderly who lose their sense of whether they are dehydrated and may not realize they are overheating. Normally their weather and house design allowed for natural cooling during the night but the heat wave was too hot through the night for that to happen https://en.wikipedia.org/wiki/2003_European_heat_wave#France
I suspect that cold deaths are more age variant as a general risk factor rather than a specific overheating event. It's interesting to have seen one study giving numbers that current warming has only reduced cold deaths twice as much as heat deaths have increased despite cold deaths being several times higher. It seems the cold is more typically a long gradual rise while the heat deaths graphs are exponential thus the balance shifts faster than I imagined
The great Moscow heatwave of 2010, blamed by Putin on secret American weather machines, seems to have killed over 11000, plus drownings and other accidents. Some deaths were due to worse air pollution.
Who dies of 12C weather & why very cold cities have fewer cold-related deaths than hot countries in Sub-Saharan Africa has everything to do with the simple fact that cold places tend to be rich and hot places tend to be poor, and poor people in hot places have exactly one way of dealing with cold weather they aren't used to -- they build fires.
Remember, we are talking about people too poor to own sweaters, or boots, or woolens of any kind. Their only shoes are sandals. They live in huts with zero insulation, because they are made for air flow in hot weather. And they often sleep outside, with thin sheets to serve as blankets, if any.
Under these circumstances, 12C or even 15C or 18C is absolute torture, especially when your body is not used to it. I grew up in a tropical country and despite almost 20 years in the US I am still miserable at any temperature below about 18C (65F). And I own all the winter paraphernalia I need!
So what do you do when it's a bitterly cold 17C and you have no way to keep warm? You build a fire, and try to keep it going all night. And you have no actual fireplace, or chimney. I wonder how many of these winter deaths in hot countries are actually a consequence of fire.
Yeah that's absolutely plausible. Hurricanes in the US kill more people from carbon monoxide poisoning than from wind or water, so I can absolutely see cold waves in hot countries killing people because of unsafe heating practices.
Working in a Midwestern inpatient hospital in the winter, you'd also see an occasional carbon monoxide poisoning due to bad fireplaces, woodburning stoves, furnaces, etc.
That seems like it happened a lot more often 40 or 50 years ago. Not citing any published data here. Just my recollection of how people - men I guess - tend to buy the farm.
I think the decline in smoking among guys and just general awareness that being 55+ and out shape makes a sudden heavy exercise experience in cold weather risky.
If this is a broader trend I would wonder if some kind of technological change has mattered. Are fewer people shoveling and more people using snow-blowers? Alternatively, a societal change could be responsible. Are old people less likely to be living independently where they are responsible for their own shoveling? I would imagine that people are less likely to live near where they grew up and thus that having the kids or grandkids do the shoveling is less likely, but maybe it's offset by more people in assisted living or something?
Maybe the growth of the service economy away from the do-it-yourself economy, with more guys with big snowplow trucks coming around to push the snow off your driveway, like in that 30 year old Simpsons episode where Homer and Barney compete to be the Snow Plow King of Springfield?
Climbers head to the Himalayas and the Andes to mountain climb in the summer and it's fairly dangerous. Not sure if an Everest avalanche tourist death in late spring might be counted as a Tibetan heat related death or not.
Death by hypothermia being more common in hotter climes actually makes a good deal of sense to me. Yes deserts are hot, but they also shed heat incredibly quickly once the sun goes down as anyone who's spent a fair bit of time in Africa, the Middle East, or even Utah can attest. Getting caught outside after dark without a blanket or warm clothing is a legitimate and widely recognized danger.
That said I don't see how that would translate to people dying of heat-stroke in Greenland. A rash of malfunctioning saunas maybe?
This was what I was thinking. You can actually get it at a surprisingly high temperatures if the conditions are right. This is especially true if you are wet. Back in the army I remember hearing about a couple of Ranger school candidates who got separated from the rest of their class at night and both died of hypothermia before they were found. They were in the Florida everglades at the time, obviously not known for it's cold temperatures. But they were wet, likely were not able to get dry, and died when they had no way to keep their body temperature up.
Just spit balling but it could be that in places that don't have a lot of developed infrastructure it's more likely you can get caught out in the rain or the like and not have an easy way of dealing with it via shelter or heating.
I don't know what the exact temperature was when those two guys died. However I have seen guys go into the first stages of hypothermia in the mid 50s when it was raining (at which point preventive action was taken). Being wet will drain heat from your body very quickly. Depending on what your clothes are made of it can actually make it worse than if you weren't wearing any clothes at all.
Which is why I'll take scorching desserts and blizzard conditions over 40 degrees and raining. Not only is it miserable it's also sneaky dangerous.
When we are talking about sub-Saharan Africa, what months are winter? Does the flu season actually correspond with the lowest-temperature months in all these places or does the fact that it's flu season in other populous parts of the world change that?
Dunno about SSA specifically but as far as I can remember in Australia and South America the flu season is usually the southern winter (June to September) not the northern one.
Not particularly happy with any of the studies either, or our ability to draw conclusions from them.
But one thing I found interesting was the global mortality rates with income-based adaptation (like more a/c) mentioned in Bressler. Logically, as people get richer, they can offset some of the heat-related deaths by investing in adaptation, and the higher emission mortality rate decreases from 6.2% to 4.2% when this effect is included (a not insignificant effect).
But one piece that is missing is many proposals for mitigating climate change (e.g. a carbon tax) have economic costs that will compound and lower global economic growth over time. If income-based adaptation to heat can have a significant impact to global mortality projections, how much of a decrease could the foregone income from lower growth rates have bought (across not just heat adaptation but all healthcare-related investments)? Isn’t it possible that the effects on mortality of having $10’s or $100’s of billions less of global GDP over a period of 60 years would swamp any direct change in the mortality rate from temperature changes like the ones forecasted?
This, of course, would say nothing about whether those costs or mortality benefits would be equitably distributed, but it’s a piece of the puzzle that is rarely pointed out in papers that seek to quantify specific costs of letting the temperature rise.
Definitely. But unfortunately, most of "benefits" of making it revenue neutral would go to the top end of the income bracket (or corporations) because they pay the vast majority of income and capital gains taxes. And I see that being particularly unattractive in today's political climate (whether rightly or wrongly). And even if it did come to pass, I would expect it wouldn't be long before calls were made to raise taxes back to where they had been to make them pay their fair share.
There's also the concern that a carbon tax, once enacted, even if initially passed in a reasonable form that considers the impact on growth, would be too tempting of a source of future government funds to keep low or revenue neutral.
In theory, an optimal solution might be a smaller carbon tax in developed countries (at a rate less than that required to fully limit or quickly reduce emission growth) with the revenue generated sent to developing countries to support their growth and the future costs of adaption. Essentially attempting to optimize the growth vs. cost tradeoff, while also addressing a more equitable distribution of future costs. But I think that has nearly zero political chance of happening and, in practice, would be subject to problems that all development aid has (like elite capture and misdirection of funds) in addition to being politically unpopular at home.
The set of people who write the cheques to pay for a tax, and the people who bear the economic burden is not necessarily the same.
What makes you think that carbon emissions, and thus carbon taxes, wouldn't increase with income? Rich people buy more goods and services.
Of course, if you want to, you could not fiddle with income taxes at all, and just hand out the proceeds from the carbon tax equally to all voters (or all citizens or so). But as you suggest, that would increase marginal tax rates, and thus be bad for economic growth.
In general, most of the time when you worry about marginal tax rates, you are implicitly worrying about whether rich people pay too much tax.
(Most of the time, because land value taxes are kind of ideal here. No deadweight losses, and still rich people bear the brunt of it.)
I am not sure I follow your ideas about global taxation, and sending money around.
As far as I see it, each country would levy carbon taxes by themselves, and cross border trade taxation would be handled like we handle VAT when crossing borders right now. No need for global coordination.
(Rich countries sending money to poor countries might or might not be a good idea. But that's independent of carbon taxes.)
I'm aware of that. My point was that, if you attempted to make a carbon tax revenue neutral, you would have to lower some other tax (or do some kind of distribution). And since most other tax is paid disproportionately by the wealthy, that would be seen as "a gift to the rich", even if the incidence of the carbon tax ended up being just as progressive as the income or capital gains tax you lowered. Also, status quo bias would mean, I think, that it's unlikely that other taxes would actually be lowered enough to make the carbon tax truly revenue neutral, given that not decreasing the income tax rate by, say, 5% is more politically palatable than increasing it by 5%.
A carbon tax-funded UBI might be a way around that (although I have seen a large constituency for that solution). I've often thought that a UBI funded at least partially by Pigovian taxes (including "sin" taxes on cigarettes and alcohol and taxes on pollutants other than CO2) made a lot of sense. Because it would mean people who contribute less than average to the externality (through their consumption) would be net beneficiaries, while those who contribute more would pay for it. Which is the incentive you want, but without the additional distortion of larger government expenditures.
Sorry if I was unclear about sending the carbon tax revenue overseas. I was saying that the optimum policy overall might be in the middle: to mitigate some and adapt some. In other words, having a lower carbon tax than would be needed to return to early 20th century emission levels but having it be offset by higher growth which makes adaptation easier. But an argument I've heard against that is that the higher growth would happen in the rich countries, whereas the costs of adaptation would be borne disproportionately by poor ones. So I was just trying to suggest something that, theoretically, might tackle both issues at once. But as I said, it's a non-starter anyway before you even consider whether it would work in practice.
Btw, the easiest way to help people who currently live in poor countries is for people in other countries (especially in rich countries) to open up their borders some more.
If you want to offset the carbon tax revenue, you can lower the marginal income tax rates for tax rates for the lower income tax brackets.
That would mean most of the benefit would flow to lower income people.
(Just straight up handing out a UBI can be seen as an extreme variant of this.)
But as said, that would increase effective marginal tax rates on the rich.
"Logically, as people get richer, they can offset some of the heat-related deaths by investing in adaptation."
This is basically the argument Bjorn Lomborg has made - and keeps repeating - in several books & articles & interviews.
Curbing global warming by moving to (presently much more expensive & less reliable) solar&wind power will reduce future GDP growth. This means we will have fewer resources available in the future than we otherwise would have, to mitigate negative effects of climate changes (in this case by building more "temperature-resistant" dwellings). Reducing such negative effects is particularly important in middle- and low income countries, as illustrated by many of the comments above.
Remember that risk = hazard x vulnerability. It is possible to reduce global warming-related risks either through (presently very expensive) policies that (hopefully) reduce the future temperature incease (= the hazard), or by policies that reduce the size/depth of the consequences that a temperature increase implies (= the vulnerability).
Unfortunately, there is a possibility that the net effect of present-day carbon-reducing policies (aimed to reduce the hazard), will end up increasing the total suffering&deaths from climate-related phenomena in the future, since such hazard-reducing policies will mean that we have fewer resources available for vulnerability-reducing policies.
California might possibly be an interesting future test case in this regard.
Except that it is no longer true that moving to Solar and Wind will hurt GDP. That might have been true when we were discussing a carbon tax to make non-renewables more expensive(thus improving renewables competitiveness). Instead we made some fixed investments in Solar and Wind which have now paid off and now renewables are making non-renewables uneconomical.
At this point sticking with non-renewables will stunt economic growth and hurt GDP.
Outside hydroelectricity, renewable currently cost more, because you need to build a back up when they don't work. Every country in Europe that has a huge percentage of renewable has a more polluting electricity because of this backup, and they pay far more for their electricity than Sweden or France, who rely on a low carbon hydro and nuclear mix.
Be careful not to confuse the price of solar when solar works compare to the average cost of solar.
What exactly do you think you are paying for solar when it is delivering 0 power(not working)? Solar and wind have made coal and other non-renewables uncompetitive. Solar energy today is the cheapest energy in history.
The maintenance, the depreciation(need to be rebuild every 25 year), the infrastructure around it, and the other way of getting power(which you must maintain even when they don't give you electricity because there is sun). How do you explain with your sources that Germany (coal/gaz/renewable) pays far more for its electricity than France (nuclear/hydro) ?
Exactly. Unfortunately, with the "with us or against us" mentality that permeates this issue, this kind of analysis can quickly get one labelled a "climate denier" and so is not acknowledged or reconciled with as much as it should be. The same could be said for studies that try to quantify any of the possible benefits of climate change (such as greening, longer growing seasons, few cold deaths).
No matter where you stand on the issue, rationally it's a shame that the discourse seems only to allow for research into things that go on one side of the scale. Because even if the proposed policy interventions are required or the best we can do, a better understanding of both sides of the equation is needed to optimize the implementation of those policies.
Yes. It is quite baffling to see how those who common-sensibly say "how about doing a risk assessment & cost-benefit analysis, just in case" are almost screamed at. I knew Lomborg's writings before he started writing about climate policies and became famous. His was your typical Danish feet-on-ground evaluation researcher, destined to spend out his days in the army of pleasant & anonymous dry-as-dust cost-benefit evaluators. Suddenly he was catapulted to herostratic fame, and/or to a social role almost resembling Doctor Stockmann in an updated version of Henrik Ibsen's 1882 play "an enemy of the people"
Here is the latest (July 20) summing-up-the-debate article by Lomborg, it is open access. I find it a quite interesting walkthrough of possible consequences of global warming:
For the record, I am not at all saying that other conclusions & policy strategies than the ones Lomborg advocate are "not rational". First, rational people may legitimately disagree about which future trajectories/estimates that are most likely.
Second, even if a group of people should agree which trajectory/estimate is the most probable, they can still legitimately hold different preferences as to their degree of risk-tolerance. An extremely risk-averse decision-rule-under-uncertainty, which Scott implicitly referred to in a former post, is "avoid disaster". If you define "disaster" as some uspecified tipping point being reached, where everything spins out of control and the Earth ends up like Venus, this means that you should fight global warming tooth and nail, even if you should regard the probability of such a dramatic spinning-out-of-control as less than 0,000x. Since it is not in itself irrational to be extremely risk-averse.
...That said, I have to add that a problem with the extremely risk-averse "avoid disaster" decision rule is that if you follow such a rule in your daily life, you should never leave your house - or vote in elections, since the probability that one vote will determine the election outcome is less than the probability of being run over on the way to the voting office (also known as the famous "Paradox of Not Voting", but that is a different discussion).
Third, people can legitimately disagree on their time preference, i.e. how far into the future they think it makes sense to compute likely cost and benefits - and rational people may also legitimately disagree on what should be the proper discount rate. Related to this, a problem I have with Lomborg's calculations is that he stops in 2100, only 79 years from now.
Admittedly, everyone reading this blog will be dead buy then, but you can legitimately argue that an ever longer time perspective is warranted.
(Then again, some could also - again, legitimately - argue that even 2100 is too far off.)
To end with my own debate preference: What I would have liked to see among combatants on both sides, is sensitivity analyses - how sensitive are the various scenarios & accompanying risk assessments & cost-benefit calculations to different specifications of the many assumptions one must necessarily make?
This is not how global warming risks & accompanying global warming policies are discussed.
(I don't really blame the journalists for that, though, for who but die-hard policy wonks would read such stuff.)
I was referring to the reaction to Lomborg's work The Skeptical Environmentalist, as I was assuming that who I was responding to was also talking about it.
Not at all. It was just in response to a study that focuses only on the effect on mortality rates.
I'm in favor of an approach that includes all costs and benefits in the analysis. So, yes, you need to look at the costs of the policy (e.g. lower economic growth) in addition to the benefits (e.g. a net reduction in mortality rates) vs. inaction (or an alternate policy).
It just so happens that effects on economic growth are particularly important because of compounding, with the added factor that growth is "fungible" in the sense that being richer can be used to offset many different kinds of harms or provide many different kinds of benefits.
That said, it's not the end of the story because certain effects may be incommensurable (e.g. loss of biodiversity, more government centralization, or loss of cultural heritage). And as I sad, it's not just the net total that matters, since distributional impacts are important (though they may have a Coasean solution).
I suspect one reason why cold cities over-adapt is that some of the important ways cold is dealt with tend to be fairly binary. That is, you aren't really optimizing houses for a particular temperature, you're optimizing them for heat retention (within some bounds, of course, but it's not a very granular decision). You either have heating infrastructure or you don't (and if you do you either have laws and norms about making sure people get heating even if they can't really afford it or you don't). Sure there's more gradation at the personal level with things like various jackets and coats being appropriate for various temperatures, but at the level of construction and governance there are big, binary choices and as they get made they push you into being over-adapted.
Three comments. The first is a point already implicit in your discussion, but one that I think you missed earlier and many people still do. Heat mortality isn't just, probably isn't mainly, people going out in a heat wave and dropping dead. Cold mortality isn't just people freezing to death. Those are dramatic examples, but probably more important are the people who are made a little worse off by heat or by cold, a few of whom die sooner than they otherwise would.
The second is something that I noticed looking at the latest IPCC report and that they, I think, never mention. The effect on heat or cold-associated mortality depends on how much warmer climate change makes winters, how much hotter summers. The report gives projections for the change in how hot the hottest day of the year will be in various places with various amounts of global warming. It has a chart showing how cold the coldest day of the year will be in various places with various degrees of warming.
I looked at how much hotter the hottest day got in hot places and how much colder the colder day got in cold places. The answer was that the coldest day in cold places got two to three degrees warmer for every degree of global warming, the hottest day in hot places got about one degree warmer for every degree of global warming. Warming makes winters milder and summers hotter but, at least for the places I looked at, the former effect was two or three times stronger than the latter. The report never made that comparison, provided the necessary information in different places and contexts for warming and cooling.
Similarly, the report routinely said that climate change had both effects but paid attention almost entirely to the effect of hotter summers. That fits my general view of the report, that the authors honestly report their results but are looking for reasons why climate change makes things worse, not reason why it makes things better. If you don't look for something you are quite likely not to find it.
I was thinking in terms of temperature extremes and had not yet read your post, so it didn't occur to me to look at the effect of warming on cold extremes in hot countries or on hot extremes in cold. Looking at those, the pattern is less extreme, but the qualitative difference remains — in most but not all places, climate change raises minimum temperatures more than maximum. I find in the Summary for Policy Makers:
"Some mid-latitude and semi-arid regions, and the South American Monsoon region, are projected to see the highest increase in the temperature of the hottest days, at about 1.5 to 2 times the rate of global warming (high confidence). The Arctic is projected to experience the highest increase in the temperature of the coldest days, at about 3 times the rate of global warming (high confidence).
My third comment has to do with the various attempts to actually measure the mortality effects. None of them should be trusted, at least until you go over them carefully. If an honest and intelligent person solves a simple problem he is quite likely to get the right answer. The more complicated the problem is, the more his answer will reflect either what he expects to find or what he wants to find. For an example outside of climate issues, consider the history of measurements of the charge of the electron.
"That fits my general view of the report, that the authors honestly report their results but are looking for reasons why climate change makes things worse, not reason why it makes things better."
I've read large chunks of the IPCC reports and well over 1000 papers on climate and this is a clear trend.
A few examples, I could give 50:
1. The exec summary of a section of an IPCC report says "We have low confidence in a global increase in droughts", but the report says (reflecting the underlying papers), some climate scientists find an increase and some find a decrease. If you skimmed through the exec summary only you might conclude that there is an increase but it's not as certain as other climate related things.
- The exec summary should say "we don't know whether droughts have increased or decreased globally".
2. A paper on sea level rise affecting megacities concludes "if we stop global warming we can delay the flooding of 1/2 of Bangkok and 1/2 of Shanghai (can't remember the exact percentages) from 2100 until 2115".
But the paper itself clearly explains that these cities are sinking at 10x the rate of sea level rise due to overbuilding and groundwater depletion.
- The conclusion, more reliably, should say "we can delay the flooding until well into 2200 if we stop groundwater depletion and overbuilding".
3. In the impacts section of an IPCC report it begins, and continues, with a litany of all the woes that will fall on sub-Saharan Africa due to anthropogenic global warming. If you read until the end of the section - of course, hardly anyone does that - you find the apologetic footnote - "Of course, this depends on crop prices being higher in 50 years time which is highly uncertain".
If it was me, I would start with that, but then no one would read on.
- The crop prices depend on economists being able to reliably predict supply and demand in 50 years time, when in advanced countries their track record of predicting GDP and unemployment in 12 months time is pretty bad. The supply depends on availability of crops, which in part comes from taking rainfall projections and feeding that into crop models and pumping that into the economic model. There are 20 climate modeling centers in the world and their models project everything from halving to doubling of rainfall in many places in the world, including sub-Saharan Africa. But, to solve the problem, we just "take the average of all the models". The crop models are not calibrated via experiment to the projected CO2 in the atmosphere, the rainfall, the temperature and a few other variables, they are just extrapolations. And no account is taken of the fact that if in fact rainfall does vary from current climate new crop variants will no doubt be introduced.
My conclusion is that most aspects of future climate, and the consequences, are unknown, apart from higher temperatures and higher sea level. Probably slightly higher rainfall globally.
Thanks for these detailed comments on the IPCC report.
My general experience from reading such expert reports (and I have read many), is that you should read the chapters in the actual report, where the scientists are allowed to write their stuff, and drop the "policy relevance" chapter at the beginning or end of the report, which is usually written by the people in the organization - and they often have a policy agenda to push.
The scientists by contrast are usually contracted in from outside universities to write various chapters, and they have their reputations in the scientific community to think of . So they usually - or at least more often - avoid "stretching the hide further than the skin allows", as we say up here in Scandinavia.
In my experience it is not the details of the IPCC reports that are objectionable, it is the media telling us "what the science says". There are certainly a few activist scientists exaggerating the possible downsides of climate change, but environmental journalism is comprised almost entirely of activists. I have been consistently appalled at how a few areas I have looked into get reported in the media (sea level, hurricanes to name a couple).
This state of affairs is not entirely surprising as the reporters at ESPN are no doubt all sports activists. However something has gone horribly wrong in climate change reporting, it is a political monoculture without peer. I literally cannot read it any more.
As I read it, the IPCC report is an honest account by people who are looking much more for bad things about climate change than for good things, so more likely to find them.
The Summary for Policy Makers is that report filtered by people trying to scare their audience and more willing to misrepresent things than the authors of the report.
That plus everything else filtered through the media is a scare story designed to get readers and persuade them of the horrors of climate change, written by people most of whom don't understand the science or much care about it.
I was reading an article about why cropland real estate prices in northwest Iowa have grown so high in this century, and one reason given was that climate change had improved the climate for growing grains in the region. That struck me because you so seldom see any mention of positive sides of climate change in the press, even though in daily life everybody hears plenty of complaints about the current weather.
There is a general "greening of the planet" tendency at the moment. However, it is hard to separate the greening effect due to increased CO2 in the atmosphere, and greening effects due to other causes, e.g. ongoing urbanization or deliberate tree planting. In Europe, forests are growing fast, but that is mainly because people leave the countryside and forests reclaim so-called "cultural landscapes".
There is also a discussion if the ongoing greening of the planet is good news or bad news. Trust humans to see a possible downside of everything. Link:
The "greening" in the article is increased agricultural output, which I wouldn't expect to reduce CO2 much. Crops get cycled back into the atmosphere when people "burn" those calories.
There is a one time consumption of CO2 when a tree grows, but a mature plant isn't a net consumer of CO2. I'm interested in greening not as a way of reducing CO2, although I suppose it does a little of that, but as a way in which CO2 has positive externalities, most notably increasing crop yield and decreasing plant need for water.
Not as knowledgable on global data as US data, but my point was that (1) US ag may (likely, but not certain) have benefitted slightly from prior warming (mostly through more favorable weather for maize in the Upper Midwest) and (2) that CC is still a BIG NEGATIVE globally, as much of the world's fertile soil lies in climates that are much warming that the Midwest (and thus do not benefit from additional warming).
Agree that, other than wheat, CO2 effects are likely to be very small.
Co2 effects should be significant for any C3 crop, which is not just wheat but everything major except maize ("corn") and sugar cane. Doubling CO2, roughly what the IPCC expects by the end of the century, raises the yield of C3 plants by about 30%.
Do you have any evidence that climate change is a big negative globally? Wheat yields are graphed at https://ourworldindata.org/crop-yields. India's yield (tonnes per hectare) has been going pretty steadily up since 1961. Their graph for world yields of various crops shows a generally rising trend, with rice, for example, more than doubling its yield since 1961.
Yeah, it's definitely true that technological progress over the past half century has overwhelmed any decrease in production attributable to a less suitable climate. But this doesn't mean that climatic conditions haven't worsened in some areas. Only that they've been more than offset by gains from improved tech and/or management practices.
Kampala, Uganda not only never really gets cold, it also has practically no seasonal variation in temperature. If someone has actually calculated temperature-related excess deaths for it, that must be from random weather changes, rather than seasonal changes.
Given that Kampala or similar places likely have no heating at all, and little insulation, a cool temperature outside corresponds to cool temperature inside. If the relation between colder temperatures and heart attacks exists even at near-room-temperatures, it's plausible that there are more heart attacks in Kampala at relatively cooler temperatures.
Scott, how long does it take you to put together a post like this? Just finding and processing these disparate sources on this out-of-left-field topic is something. But you actually synthesize them into a meta-study, which you wrap head to toe in engaging prose. (Or are there some behind-the-scenes researchers or editors contributing to this production?)
Feature request: Provide subscribers an estimated Hours To Produce figure on your posts?
This one probably took between 5-10 hours, although it's hard to tell because I'm bad at working straight through as opposed to switching back and forth between tabs.
I don't know if this is supported by evidence at all, but I think it's one possible solution to the paradox: suppose that temperature-related deaths are, for whatever reason, extremely non-linear with temperature. For example, suppose that you get 90% of heat-related deaths between 95F and 100F and 90% of cold-related deaths between 60F and 50F. Then in the hottest countries, heat-related deaths might be spread so evenly through the year that you couldn't identify a relationship between hotter days and more deaths. Similarly for the coldest countries you couldn't identify the cold-related deaths.
But even if something like this was going on, I think it could only explain the very hottest and coldest countries - if the trend holds up when just looking at the countries in the middle, then I don't think this would explain anything. From eyeballing the graph it seems like the trend does hold for the middle countries.
> Everyone says that global warming will worsen mortality from heat. I’m a bit confused by this also
There's an asymmetry here that might be worth noting: when it's cold, you can usually put more clothes on to warm up. There is only so much you can take off when it's hot.
(I've always found that frustrating, because I'm increasingly incapacitated by temperatures beyond 75F.)
A possible explanation for the data in Bangkok and other tropical parts of the world - the "cold" season is not just winter, it is also the rainy season when the disease burden and mortality go up every year due to a whole host of diseases of which flu is just one of them. Examples of other illnesses include dengue fever and leptospirosis.
This is certainly the case in my home state in India, Kerala. Mortality goes up in the rainy season which is not cold by any measure. But the absence of sunlight, presence of stagnant water etc probably does as much damage as colder weather does elsewhere.
I think these sorts of studies miss some huge confounding factors related to some of the details that excess death numbers just cannot get at. In Michigan, where I live, we get a few pretty severe hot days in the summer and a few pretty severe cold days in the winter. When it’s severely hot out, we have old people dying in un-air-conditioned homes, since many here still don’t have central air and many old people cheap out about putting in window units until it’s truly hot out, not to mention farmers and construction workers who have to work in the heat. On the other hand, we get fairly few direct freezing to deaths in the winter because everyone has heat and most people avoid activity when it’s that cold. We get far more winter deaths from icy roads or heavy snow or the heart attacks from shoveling snow than from the temperature per se. This is compounded by the fact that below about 0*F we tend not to get much snow, so much of the direct causes death decrease below a certain temperature.
I think this analogizes well to the pandemic, actually. Despite the lockdown orders here, and despite the number of people working from home, traffic deaths went up in 2020 vs 2019. Way more people took advantage of empty freeways and the state troopers explicitly saying that they weren’t going to interact with people early in the pandemic just to write tickets to do dumbass car racing at 120 mph on the freeway and wrapped their shiny Shelby 350s around a bridge abutment. Similarly, some of the stay at home prevented flu deaths, but increased, say, cancer deaths due to delayed diagnosis. These things are often deeply complex systems with complex causation and I see no reason why temperature related deaths would be different.
The thought is that I am surprised you didn't mention increased traffic fatalities as one of the possible contributors to excess cold deaths. Obviously less relevant in places that don't get snow/ice in the winter, but where I am from traffic accidents do go up considerably once the roads are covered with winter yuck.
The anecdote:
It probably doesn't shed any direct light on the human data, but when I was growing up my family saw a very clear pattern in seasonal mortality of our flock of pet chickens. We typically had around 20-25 at any given time, and most only live to 9-11 years (actually somewhat bimodal with a peak at 5-6 and the other around 10) so we got a fair number of data points, and deaths of 'old age' clustered around early winter and mid spring. The early winter makes sense, they had an insulated chicken coop with an electric water heater and an electric heater in the coop, but they were still essentially living outdoors and the cold is an extra source of stress on the oldest/frailest. But the odd thing was the spring peak, which was actually the higher of the two. it was before the summer heat came in, but still well into spring and we could never figure out what the stressor was when the weather was that mild except that it must have something to do with the change in temperature moreso than the absolute temperature, especially since the winter peak was well before the coldest part of the year.
Interesting about the traffic accidents. I've long had in mind the statistic that where I live (Northern Europe) there are four times as many motorcycle accidents in the summer as during the winter. Although it's initially counter intuitive, the important hidden information is that there are six or seven more motorcycle-miles ridden in the summer, and in the winter it's only the hardcore pros who are still out on two wheels.
We have a flock of 'pet' chickens too, but I'm afraid the data I have on their seasonal mortality is overwhelmed by the confounders called foxes and pine martens. And the fact that if the chickens survive long enough for us to notice their egg-laying has diminished, it's usually time for us to put them in the oven. We don't have many that make it to four years old, but though their lives are relatively short, I like to think they're full of chicken-joy..
In the U.S. traffic fatalities were up relative to miles driven in March-May 2020, but the real explosion in road deaths were up 36% in the last 7 months of the Racial Recockning of 2020 among blacks but only 9 % among nonblacks. It's almost as if the media-declared "racial reckoning" convinced blacks that the white man's law didn't apply to them. Thus black road fatalities in June 2020, the first full month of the Racial Reckoning, were 55% worse than in June 2019.
It's almost as if when the Establishment declares that rule of law no longer applies to blacks, who are now morally entitled to resist arrests, then blacks tend to shoot enough other more and kill each other more in car crashes.
Don't extreme temperatures cause mortality in a lot more ways than listed here? They just sort of generally take a toll and make you more likely to die if you're sick, heat makes people more violent, cold makes people less social, etc. In places that aren't super food-secure they cause famines.
Just so I've got a handle to work with the equal and opposite ideas of more cold deaths in hot places and hot deaths in cold places, I'm going to refer to them collectively as environmentally oppositional deaths (EODs). So my first thought was that the EODs might be caused by excessive environmental controls: setting the A/C too low in hot places and cranking the heater too high in cold places.
There's a meme in some places that the weather forecast is always wrong (statistics to the contrary notwithstanding). In places where this idea is pretty widespread, would people develop a habit of compensating for how wrong the forecast is? Would this lead to unexpected extremes, ones bad enough to up the number of EODs?
Anecdotally, recently a small cold front went through, so we turned the heater on for the first time this season to brace for it and to get the cobwebs out for the months ahead. Unfortunately we didn't know how small the front actually was, because in the middle of the night we were woken up by how hot it was. I checked the thermostat, and while the heater was set to only 70, the temp gauge said it was 77 in the house! That's 7 degrees of difference, and compared to the usual climate here, that was a rather mild night. If something like this happened in a place with more extreme temperatures, I can't imagine how bad the temperature differential might be from such a mistake, and how many EODs that might lead to.
This does not fit the pattern in countries like Saudi-Arabia, where people (have to) stay inside in summer due to the heat. The flu wave is still in winter.
Still, it's one of the best explanations that we have, even if it does not match all countries.
Another one is that UV radiation is stronger in summer, and is really bad for airborne viruses. But I also think that it doesn't really fit for countries like Saudi-Arabia, where UV radiation inside of buildings is probably not an important factor.
I would like to see these numbers controlled for schools in session. I find it highly likely that many seasonal diseases are seasonal because schools are usually packed full of children who pass illnesses to one another, are often asymptomatic or lightly symptomatic, and then go home to their families who are more susceptible.
This seems very plausible - I caught Covid from my daughter, exactly when the lockdown ended here (Czechia) and she started going to school again. Also, the lack of flu last year may be explained by the widespread use of respirators + lots of online schooling in most countries.
But then seasonal diseases wouldn't be seasonal, they would be...three-quarters-of-the-year-al, and we wouldn't expect it to be any worse in December/January/February than it is September-November or March-May.
This feels like the kind of post where it might be worth just calling up someone in the field and asking them questions for 45 minutes. I know that has never traditionally been the format of this blog but it would probably be a shortcut to a lot of interesting stuff that hasn't been synthesised in any published papers yet. In my experience, not every scientist you email will want to talk to you, but a lot of them will.
One point which has not been stressed here at all is the role of humidity especially for feeling cold. The effort to keep up a certain temperature increases with humidity due to higher heat capacity and conductivity of wet air (20C in water is quite different than 20C in air). This effect should be expected to be higher in warmer regions where humidity is higher and the number of layers of clothes is less.
We have examined relationships between mortality and cold and hot weather effects in Hong Kong. Basically the cold weather effect on mortality is pronounced and is independent of influenza rates. Also almost all causes of death are affect (except for cancer and accidents) not just cardiovascular deaths:
Hong Kong is a good place to test this as the weather during winters varies considerably. During some winters temperature rarely go below 15C while others have been characterized by long cold spells (by our standard a cold spell has temperatures < 15C). During those winters with colder temperatures we see a lot more excess mortality. So not seasonal (at least not here).
Seasons in the Andes are not like seasons elsewhere. Winter is sunny and dry, with blue skies; summers are damp, and it's cloudy, and not that hot. (There are also mudslides during the summer, but much of their damage is to lowland regions lying further downstream.) Yes, in winter, it's chilly in the early morning, or even mid-morning if you are in the shadow (and it's temperatures in the shadow that are usually recorded, no?), but there's plenty of radiant heat from the sun. Of course too much UV can also cause problems, but generally not immediately - you could get skin cancer or sight problems later on. I'd certainly say winter *feels* healthier (to me, and to anybody else who is somewhat affected by asthma/allergies), at least in the regions that Peruvians think of as having "moderate altitude" (< 3750m or so).
While we are at it: global warming affects much more than just ocean levels. Andean glaciers are melting rapidly. Momentarily, the effect is not entirely bad (more water! good harvest! ah, ok, mudslides, but those are partly further down), but in the medium to long run, it's bound to be pretty terrible - without glaciers and less rainfall, the entire region could become basically uninhabitable (or really uninhabitable, according to some projections).
I'd expect regions to adapt according to comfort, which might be more than is needed to not die. So from a perspective that's only about death rates, it looks like over-adaptation.
Accidents are the number 3 cause of death (in the US anyway), and it seems plausible that you’re more likely to have an accident when extreme conditions force you to do things differently than normal. Maybe?
Also, FWIW, if their model uses 0.5 degree latitude by 0.5 degree longitude squares, that means the equatorial squares are much larger than the polar “squares”, though I’m not sure that helps explain anything…
I don't have time to check this carefully right now, but keep in mind that car crashes occur more frequently during cold months. Northern countries have methods of dealing with slippery roads such as spreading sand or mandating use of snow tires on vehicles. I assume that warm countries do none of these things and instead get surprised when the occasional cold month hits them.
My personal experience is that the change in temperature or any environment is a challenge to the body. 16°C in October feels cold, the same temperature in April makes me thinking about wearing nothing but a t-shirt (and if you see people wearing t-shirt in April - that are tourist from scandinavia visiting Germany).
How does this effect sub-sahara africa? People are used to constant temperatures during their whole live, and they are not trained to handle changes. I know a man in Bujumbura, Burundi, who went to hospital in Nairobi, Kenia. He felt uncomfortable because it was too cold (and we are talking about 10°F colder temeratures).
So the environmental changes could be more challenging to people in areas with less seasonal differences.
1) You don’t buy the idea of 12C being a dangerous temperature, but have you ever spent a significant period at that temperature in an uninsulated building/outside? It’s freezing!
2) That said, Kampala’s annual temperature curve is basically flat, with a daily mean of 22-23 C all year. The way the main paper fits functions on top of functions, it seems inevitable that trying to draw a signal out of a 1C range will result in nonsense.
3) Nepal/Tibet could be related to the the monsoon, which coincides with high temperatures.
4) Does this post on the harms of cold have anything to do with your time in England?
Re: #1 - yes! I have spent July nights in Malawi, where daytime temps are around 25C; but during the night, it can easily fall as low as 5C. If you're sleeping on a floor, with no mattress, and little by way of blanket/covering, and your diet is extremely poor ... well, it's no fun. Not sure it would necessarily be lethal, but still, for some it could be. (And altitude is surely a compounding factor in sub-Saharan Africa.)
I wonder whether the variability of temperature could play a role. That is a sudden heat wave or cold snap is worse for mortality than if it is always pretty cold or pretty warm. The nordic countries that have low winter excess mortality also have pretty stable climates. Iceland which had no winter excess death has a really low temperature variability (at least in the populated parts). Reykjavik has a daily mean of 0.7C in January and 11.6 in July and record cold of -20C. Nome in Alaska is at the same latitude and has a daily mean in January of -15C and record low of -54C.
- R-nought for the flu gets above 1.0 in the temperate northern part of the world in, say, November-March and in the temperate southern part of the world (e.g., Buenos Aires, Melbourne) in May-September.
- People from the temperate world travel to the equatorial world more or less year round.
- Temperate people are more likely to bring flu with them in their homeland's winter and infect equatorial people they are visiting.
- There are vastly more people living in the temperate north than the temperate south.
Prediction: More equatorial people get flu in the Northern winter than in the Southern winter.
Stockholm is actually not very cold. The average minimum for January is -3, same as New York, as compared to -21 in Novosibirsk. Still, it's cold enough that I'm surprised not to see any mention of the lives lost to slipping and falling on ice/snow (I think about half a percent of deaths), or the QALYs lost to injuries from slipping and also from the fear of slipping and the isolation brought by such fear (among the elderly).
Best scientific treatment I have seen so far on variations in temperature-deaths, and a nice open-ended discussion of possible implications of global warming.
Scott asks the question: Is it reasonable to assume people in cold climates over-adapt to the cold, relative to people in the South? (quote: "Why would cold places adapt so hard that they did better than warm places?")
I think a theory can be formulated. At least I have got one, based on living in the North of Europe and sometimes travelling to the South of Europe to escape winter – only to find myself almost freezing to death in some rented house in the South. (Ok, n=1, but wait for the theory)
Here is the theory: People in the North know that when winter comes and it gets cold, it stays cold for a long time. You cannot wait it out. So you have to put in the money to get central heating and those triple-glassed windows.
While people in the South know that when it gets cold, it usually does not stay cold for very long. If you brace yourself, the cold spell is usually over in three weeks max. You can brace yourself to live through three weeks of cold, but not four months. So you do not adapt at all.
Plus, to some extent people in the South must do the opposite: They adapt their houses to the often very warm summers. That is why I have never frozen more than in the South. Old stone-built country houses in particular (where old people often live), are built to keep the heat out in summer. Which makes the houses ice boxes in winter.
…for US people, a similar logic is captured by Mark Twain’s dry observation: “The coldest winter I ever lived was a summer in San Francisco.”
Finally getting to the testable hypothesis: If I am right that people in the South sit out the cold while people in the North adapt to the cold, we should get excess cold deaths in the South, but only in years with unusually long Southern winters; i.e. when the presumption that “the cold will pass” is not borne out. Scott’s information that cold deaths usually take place 14+ days after the cold spell starts, fits with this assumption.
To test this hypothesis we would need data not only on winter temperatures in different countries and across time, but also variations in how long the winters last. Cold deaths in the South should peak in years where winters surprise everybody by being long.
Finally, a bit of travel advice to ACT readers: Be careful if you live in the North and are tempted to rent one of those picturesque and suspiciously cheap old rural stone cottages in the South to escape your own winter! Speaking from bitter experience….
In the US we have a similar phenomenon with the snow. In North Carolina where I live we get 0-3 days of snow a year and after a snow it is melted and gone within 2-3 days.
Consequently no one either individually or publicly invest in snow removal equipment. We don't salt most of the roads, we don't have lots of snow removal trucks folks don't have snow shovels.
When it snows the city just has a couple day holiday where no one leaves their home and schools are closed. But in Michigan where my wife is from they know it will be an all winter affair so their schools shut down less frequently for snow than ours do.
Confounding this is the fact that Scandinavian countries are not only prepared for cold weather, they do so in rather safe ways. Electrical or natural gas heating, or when wood is burned it is in airtight stoves with well-maintained flues. Here in Nova Scotia house fires and flue fires are common winter occurrences, but we can't afford to do things as well as the Scandinavians. But consider the case of sub-Saharan Africa: most cooking and heating is done over indoor open wood fires in rural areas. Even in cities the electricity supply is unreliable. Open fires mean increased COPD from breathing smoke, and that in turn means respiratory infections are likely to be more dangerous or even lethal. My wife started an orphanage for AIDS affected or AIDS orphaned kids in Kenya, and goes there yearly. She notices how they feel the cold - even when it seems hot to her they will put on coats as 20ºC seems bloody cold to them. So more wood gets burned. More risk of fires, and more respiratory infections from huddling indoors, and those infections will be more deadly in lungs that have been inhaling woodsmoke. Add to that the immunosuppression and general weakness from endemic TB, malaria and AIDS, and you can see why deaths skyrocket in the cold season. One thing we have done is to encourage the use of rocket stoves, which burn less wood (in short supply) and produce far less smoke. There is even a charity dedicated to encouraging their use - see https://www.aidafrica.net/rocket_stoves/
Would you not say that perhaps this indicates that economic growth/higher GDP per capita, allowing Africans to afford rocket stoves (rather than to get them through charity), might be a good idea...
...and perhaps an even better idea would be to get a big coal/oil/gas burning plant that provides stable&cheap year-round electricity to them and their neighbours & nearby towns, so they would not have to burn wood at all.
That may increase longer-term problems, but as you illustrate it would reduce a lot of rather immediate present-day health risks & problems in sub-Saharan Africa.
Just a possibility.
One would have to do a lot of risk assessments & cost-benefit calculations to be reasonably certain a shift in sub-Saharan Africa from wood (or nothing at all) to coal/oil/gas would reduce more problems than the risk of creating problems in the future.
It seems like what you're getting at is that cold places don't just "over-adapt", they adapt in fundamentally different ways. They adapt in rich-people ways, and rich-people adaptations
(that is, adaptations which take advantage of large amounts of wealth) reduce mortality more than poor-people adaptations.
I'm taking the liberty of posting before reading all the comments. If lack of sunlight is a factor in winter deaths, then there should be a weaker winter death effect closer to the equator, even allowing for warmer temperatures.
If excess mortality is caused by temperatures outside the usual range, then moving the range up isn't going to lead to fewer deaths from cold.
For reasons I'm not going into, I live in Philadelphia without air conditioning. This gives me a different understanding of the effects of challenging weather than a lot of other people seem to have.
The high and low temperatures only give a modest amount of information. For *how* *long* was the temperature at or near the high? What were the lows like-- how much of a chance does the house have to cool off at night?
The worst summer weather I experienced was in Philadelphia in 1995. Two weeks of high of 110F and low of 85F, with high humidity. The air felt like it was so heavy it was hard to breathe.
Incidentally, the past three summers here have been relatively tolerable. Previous, the humidity was always pretty high, and I thought that it was inevitable because I'm living between two rivers. That theory is wrong-- the past summers have been at least as hot as the usual (highest temperatures in the 90Fs), but with moderate humidity. I have no idea what's going on.
From experience living in a multicultural family, I believe the over-adaptation to cold is true.
The (simplistic) rational is as follows:
- If you do not wear the appropriate clothing in mild European climate in winter, you might catch a cold. Big deal. People end up wearing unappropriate clothing out of laziness, wanting to look cool/strong (teenagers), and eventually habit.
- If you do not wear the appropriate clothing in Russian winter, you... die. Hence people are much more careful, and the intensity of this effect is non linear.
Slightly counter-intuitive, probably controversial, but all my personal data points support the hypothesis so far.
I haven't read the papers, but does all of this relate to natural deaths only? Because I would imagine there to be a pretty strong link between suicide, car accidents, falling etc. with the cold (and thus dark) season. Sure, these don't make up the lion's share of deaths, but they surely play a role.
It's really hard to hypothesize about causes without more info, like:
- Separate deaths from transmissible diseases
- Separate deaths from exposure itself (i.e. "freezing to death")
- Attempt to account for "when people spend more time indoors" - this probably varies a lot by region, as some regions consider it "too cold" at different times than other regions. It's not settled fact that flu spikes in winter for ventilation-related reasons, but it's at least part of the equation. Related interesting question... when it's way too hot and everyone stays inside, does that lead to more disease transmission?
Thanks. I realize people are quite confused about this; someone even asks if hot places have winter. But I want to remark at least three main issues with this whole analysis that make me very suspicious about cross-country comparisons regarding deaths, temperatures and seasons:
1) CONFOUNDERS: distinguishing the “temperature factor” and “winter factor” is harder than we think, especially if what you want to measure is the impact of climate on health. It’s not just that there are too many confounders, it’s hard to define what is a confounder and what is causally relevant. For instance, winter is the dry season in Brazil: prices and allergies (because of dust) spike; global warming will likely make this worse. On the other hand, in higher latitudes, you have way less sunlight and significant behavioral changes; global warming may or may not help with that.
2) ADAPTATION: I wonder if physiological adaptation is underestimated. Acclimatization takes a while to be optimal – think about adaptation to changes in altitude; so, gradual transitions between temperatures should be optimal. But in tropical climates, you don’t have that: living in Sao Paulo, you can have 30ºC on a hot dry winter day, followed by a cold or hypothermia with 15ºC on the following rainy evening.
3) VARIANCE and MEASUREMENT: notice that some of the linked papers (those I checked, AT LEAST) used data on the average temperatures (usually the mean between the max-min on the same day). Not only this neglects wet-bulb temperature and windchill factor, it also equates a wet day with min of 15ºC and max of 35ºC (I hate those days) with a pleasant dry day ranging around 25ºC.
I wonder how the results would look when compared with seasonal temperature variability, as opposed to how hot or cold it gets on an absolute scale? Humans seem to benefit from a certain amount of variance, so maybe people who live in places where the annual temperature is between -10F and 60F are better adapted to deal with general physical stressors than people who live in places where the annual temperature is between 70F and 90F.
1. Let's say someone had a heart attack/blood clot because of a cold day. You'd expect to see increased mortality about a week or so later, because, while some people would just drop dead, others would go to the hospital and die there. A group looked a weather variables and incidence of DVT (blood clots) and found that around 9-10 days after a rainy day, or a windy day, or a day with low atmospheric pressure (more on that below), there was an increase in blood clots about a week later (source: https://pubmed.ncbi.nlm.nih.gov/19806252/#affiliation-1). It seems more plausible that these effects are mediated by inactivity than the effects of weather on our physiology.
2. Hawaii has VERY little variability in seasonal temperature (coldest month with a high of 80F, hottest with a high of 88F), but has about the same seasonality to respiratory infection and cardiovascular disease as other places with more variable temperatures (source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC28593/pdf/1946.pdf). Please click through and look at how smooth the temperature curve is while the respiratory infection and cardiovascular disease curves whip up and down every year. It just does not seem biologically plausible that temperature effects on physiology could account for such a significant amount of variation. Another way to say this; I don't think increased blood viscosity or peripheral vasoconstriction due to *slightly* colder weather could be causing increased cardiovascular mortality in Hawaii.
3. Inactivity is high associated with all cause mortality (https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2783711) though it's tough to determine causality since maybe people who are sick for other reasons move around less rather than moving being protective (though it does seem that a preponderance of evidence suggest that, all things being equal, not moving around much is bad for you-if anyone thinks there's good evidence to the contrary please let me know).
4. Re: association between low barometric pressure and blood clots I brought up in (1). I think even a short period of inactivity (I'm talking a few hours) likely significantly (but slightly) increases your risk of death in the short term. Case in point, physicians are trained to ask if you've recently taken a long flight when you come in with a blood clot. The reason is that the way blood returns from the legs back to the heart to get recirculated is by being squeezed by the leg muscles during normal activity. When you sit in a cramped airplane for a transatlantic flight, you might sit more or less perfectly still for >6 hours. Blood that's not moving is MUCH more likely to clot, and so you can get a blood clot.
The authors of the weather vs. clots study noted the strongest association between low atmospheric pressure and incident blood clots. I interpret that to mean that days with low atmospheric pressure (overcast, windy, rainy) correspond to lazy, inactive days at home. They wonder if there's a link between the low cabin pressures in airplanes and blood clots, in addition to the activity. Not sure how you would tease this apart.
I don't understand the definition of "cold-related death". Is it strictly death from hypothermia ? Is it death from seasonal illnesses, which are caused by the cold ? How far up the chain of cause and effect are we going to follow ? If a person is driving his car to work one day, hits a patch of black ice, spins out of control, and plows full-speed into a pedestrian, then did that pedestrian "die from cold" ?
>"It separates the world into a grid of 0.5 degree x 0.5 degree squares. It uses a bunch of assumptions and interpolations to get a dataset of daily average temperatures and mortality rates for each square over ten years. Then it calculates a function of how mortality varies with respect to temperature. The lowest point of that function, usually a pretty normal temperature, gets dubbed “the minimum mortality temperature” or “MMT”. Then they calculate how many extra deaths happen compared to the counterfactual where it was always the MMT, and they get five million."
It looks like they're just doing an excess deaths above the base rate type calculation based on temperature changes, I don't think they are looking at cause of death at all.
Well, yeah, but that was kind of my point. Does it make sense to just attribute all excess deaths to a single cause, such as cold ? In that case, why not the price of milk ?
First, the causes of death. Heat-related causes of death are generally pretty direct; dehydration and heat stroke. They also predominantly hit the medically frail, but will also hit those with less experience with heat worse; as somebody who has lived in one of the hottest places in the country, I recognize the symptoms of heat exhaustion, and immediately rectify the situation. Somebody without experience with heat might not notice their heat exhaustion until they're too mentally addled to actually do anything about it.
Cold-related causes of death include both direct and indirect causes, however. For direct, there is hypothermia and exposure, which I think will predominantly affect the medically frail. But there are also cold-related accidents (slips/falls and traffic incidents), and also being snowed in, which can cause people to die of apparently unrelated accidents (bleeding out while waiting for an ambulance after a kitchen accident). These can be mitigated to a significant extent by appropriate local investment (snowplows, salting and sanding roads), but this is only done if it makes sense to make that investment.
For the indirect cold-related deaths, I think are notable in that they are not as limited to the medically frail. I'd hazard a guess that the average cold-related death costs far more QALYs than the average heat-related death.
Re: heart attack deaths, the paper you linked seems to be about blood thickening below a specific temperature rather than relative to local baseline. So maybe places like Stockholm are cold enough year round that people's blood isn't much thicker in the winter than it is the rest of the year?
It seems to me that the explanation about vulnerable (near death) populations is the most probable. It explains the lag time between cold weather and deaths (they get sick first) and also the tendency to be opposite in cold verses warm locations. A location that's unusually warm may help stave off a person getting sick, but a 10-20 degree temperature drop, even if the resulting temperature is well above what's needed for survival, would be enough to take their already frail body to a place where death is much more likely. In a truly cold place, that person would have gotten sick and died earlier (general death statistics regardless of temperature), or have been placed in a location where temperature differences are less of an issue - i.e. the insulation discussion, where Swedes are used to being cold and better prepare their populations for it.
In this theory, it's not acute cold that causes death, but instead lower temperatures that result in sickness and then death. Heat deaths, on the other hand, tend to be more sudden and directly related to high levels of heat, but would affect similar populations. Heat deaths come from heat stroke and other direct effects, rather than opening a person up to sickness.
Did you consider traffic fatalities in the winter? Anecdotally and from basically everybody I've spoken to, winters are more dangerous for driving due to snow, slush, wetter conditions, overcast etc.
It’s kind of fun to figure out where in the world commenters are sitting at their keyboards.
Unless they make an explicit mention of their location it’s enjoyable to see what can be inferred by their units of measure, local season mentioned, acronyms used or distinctive spelling of English words.
I am amazed by the global reach of ACX. Western Hemisphere and Eastern. Northern and Southern.
Our host has touched on how his readership has spread since his - I’m searching for neutral terminology here - let’s just call it interaction with the NYT.
No doubt it was traumatic at the time but the result sure seems like a long term net positive.
I'm wondering if that's a missing factor here. Is it less about the temperature and more about the humidity and whether it's raining? I'd be curious to see what mortality is like during rainy vs sunny periods, since that seems to correlate with temperature and could resolve the confusion about why the temperature differences for when mortality starts going up are so big from place to place.
I can't cache this out in detail, but I wonder if the odd global MMT results are partly just statistical artifacts. Like, sometimes the tails of distributions are the weirdest, least-normal parts (so maybe hottest and coldest places will break the model), and grid squares with smaller populations will have higher variance (e.g., Greenland must have a small population; thinking of that Andrew Gelman county-level rates of stomach cancer example).
I once treated someone for the beginning symptoms of frostbite in 60°F. I was so surprised I checked her several times before bringing her in and beginning treatment.
"I find this hard to analyze because I still don’t really get why cold cities over-adapt and end up with even lower mortality than the warm ones."
Just a theory. But because cold cities *know they are cold*? Whereas in warm cities, any increase in death might either not be particularly noticed, or not attributed to the temperature - because that possibility simply won't enter citizens' or policymaker's minds. After all, they're not cold cities!
Put another way, 'cold-related deaths' are simply more salient in cities that are already cold.
"I think the idea is something like if an extreme weather event kills lots of people one year, the next year extreme weather events will kill fewer people than normal, because a lot of the vulnerable people are already dead."
I wonder if there is evidence for this from, say, bad flu seasons - or indeed covid.
Extremely low confidence explanation for some of the weirder data:
Perhaps the human body, over long periods of time, adapts to given temperature ranges? Eg, someone from Uganda might find 80 degrees to be uncomfortably cold, with some of the associated dangers, as it’s on the low end of what their body has experienced. I don’t know enough to propose any mechanisms for this, but it seems like the sort of thing biological systems would cook up.
Anecdotally, I’ve known transplants from Florida to NYC who complain bitterly about temperatures that a local person would find quite comfy (~70 degrees).
Your central source (Zhao et al) didn’t collect data on mortality in the places you’re most curious about -- Tibet, Greenland, central Africa, etc. They collected data on mortality in 43 countries (see fig. 1 -- it’s mostly high-income or middle-income countries) and used that to train a model that predicts the temperature-mortality function based on “meta-predictors” like GDP/capita and Köppen–Geiger climate classification. They didn’t look at any mortality data on Greenland -- they just look at the meta-predictors for Greenland, and use that to predict the temperature-mortality function for Greenland. They use that, plus Greenland’s population and temperature history, to guess how many heat-related and cold-related deaths it has. So the lack of curiosity about Greenland isn’t because they’re ignoring a strange real-world phenomenon -- it’s because they’re ignoring the strange behavior of their model at the edges of its distribution.
Note that Tibet, Greenland, and the Andes are all in the same Köppen–Geiger climate classification -- “ET” on the Wikipedia map. It seems likely that the training data included some Andean location with weirdly high mortality sensitivity to warm temperatures, and the paper’s model generalized from that to the few other populated areas with climate classification ET. Maybe that was a good generalization! Maybe whatever is causing high sensitivity to warm temperatures in the Andes is also true in Greenland. But the paper doesn't have Greenland mortality data to test that.
Exposure to cold temperatures has been shown to encourage fat loss and possibly help with diabetes. There are multiple mechanisms: other than simple thermodynamics, the human body adapts to cold temperatures by producing brown fat, which consumes calories to produce more heat in order to maintain body temperature.
This could explain why people in colder climates seem to be doing better overall: they're losing more fat naturally and improving their BMIs.
This link is a decent starting point, if you want to know more you should search for Ray Cronise (a former NASA scientist) and Tim Ferriss, a health and fitness author. They were among the first to popularize this effect AFAIK.
Scott, you spend a lot of this post discussing whether seasonal effects (rather than temperature effects) are driving the cold-weather deaths. But I think the paper is trying to control for seasonal mortality effects, and just focus on the excess mortality (excess relative to seasonal trends and other trends) associated with cold (or hot) days.
“...in the first stage, the temperature–mortality association for each of the 750 locations was estimated by use of a quasi-Poisson regression with a distributed lag non-linear model… where… ns is the natural cubic spline for time with eight df per year to control for long-term trends and seasonality”
They might do a bad job controlling for seasonality! But I would be very surprised if the cold-weather mortality they observe is mostly seasonal.
> I’m not really impressed with the people working in this field. Most people don’t clearly say that excess winter deaths are a combination of season-related (from the flu) and cold-related (from cardiovascular) deaths, even though something like this has to be true.
I think the reason they don't discuss season-related stuff like flu is that they are (attempting to) control for seasonal mortality trends.
I’ve dug into this literature for a previous project. Despite the model’s strange behavior in low-population areas, my sense is that it’s probably doing a decent job estimating the temperature-mortality relationship in rich and middle-income countries. But if you want to use any of this to make inferences about the mortality cost of climate change, you need to reckon with a few other details:
The paper’s training data didn’t include any low-income countries. (See my comment on Tibet and Greenland, for a discussion of how they only train their model on a few countries.) The closest they get is the Philippines, a lower-middle-income country. (This is a welcome addition -- previous papers in this literature, like that from the Climate Impacts Lab at Chicago, only used upper-middle income countries like China and Brazil.) From what little data we have, it seems like infant mortality is much more sensitive to high temperatures in low-income countries. (See https://www.nber.org/papers/w24870. This makes sense: if you can afford any climate control -- a swamp cooler, a neighbor’s cellar -- you use it to protect infants on a hot day. So infant mortality is a lot less sensitive to heat in lower-middle income countries than low-income countries.) So, if you use this paper to estimate the effects of warmer temperatures on mortality, you’re going to miss a lot of infant deaths in low-income countries.
The papers you’re citing combine deaths across all ages. But the excess deaths on cold days are concentrated among the elderly, whereas infants disproportionately die on hot days. (You can get this result by playing with the data from the appendices of this paper: https://www.nber.org/papers/w27599) If you care more about the death of an infant than an elderly person, then this pattern will significantly increase the net mortality costs of warmer temperatures.
When economists try to turn these temperature-mortality functions into a “mortality cost of carbon”, they often assume perfect adaptation -- i.e. if temperatures in Delhi start to look like Kuwait City, well then everyone in Delhi will live like people in Kuwait do. Never mind that they may not be able to afford the air conditioning that makes Kuwait livable.
And then of course, none of this captures the mortality cost of stuff like climate-induced migration. Desertification of the Sahel, flooding in Bangladesh -- those are going to drive migration and conflict, and those mortality costs will be significant too.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3606398/ has some data on hypothermia in infants which suggests that infant mortality rates in poorer countries may in fact be quite sensitive to cold temperatures, with effects on mortality up to 28 days after the observation of hypothermia. See in particular the section on environmental correlates with infant hypothermia.
"Why would cold places adapt so hard that they did better than warm places? I don’t know, but this is what everybody says."
Adaptations aren't continuous, they're discrete - e.g. if you already have a heating system, if it gets extra cold you can turn the heat up a little more, but if you have no heating system you will die.
> When you’re skeptical of complicated models, sometimes it helps to go back to the rawest data you can find. So here’s a graph of mortality rates in New York City over time.
But that's not the rawest data you can find. The rawest data is the number of people in New York City before checking what rate they're dying.
> If growth mindset was so great, you would expect fixed mindset people at Stanford to be as rare as, say, people with less than 100 IQ are at Stanford. Given that you will search in vain for the latter but have no trouble finding a bunch of the former for your study on how great growth mindset is, it sure looks like IQ is useful but growth mindset isn’t.
But I would drift one degree away from the rawest of data, because there's an elephant in the room: wealth. You talk about "cultural adaptation", but a lot of "cultural adaptation" is pretty obviously only posssible with large amounts of wealth.
> The worse your climate, the more likely you are to have good central heating.
Good luck having good central heating without wealth.
> Stockholm doesn’t get any increased mortality from the cold, no matter how cold it gets. Plausibly that’s because they’ve organized their lives and built environment around surviving cold winters.
There are a lot of people in Stockholm. But Stockholm is very wealthy. If Stockholm were not so wealthy, they would not be able to sustain so many people in such a hostile environment.
> I’m not entirely convinced by this story. Shouldn’t this mean that everywhere has the same level of excess death from the cold? Why would cold places adapt so hard that they did better than warm places? I don’t know, but this is what everybody says.
Cold places adapt better to everything. And yes, cold places really do adapt so hard that they do better than warm places. And the reason for that is because having a large enough population to be studied, in a cold place, is very very very strongly correlated with wealth. Cold places, or rather, the people *in* cold places, are wealthy, and wealthy people adapt better to any environment.
And why are large populations in cold places necessarily so wealthy?
There are places on Earth that reached large populations despite lacking great wealth. All such locations have one thing in common: they are warm.
This patterns *jumps* out of the data. You will search in vain for cold regions that reached large populations before acquiring large amounts of wealth, but warm regions have no such difficulty.
The one thing we can say a priori about the winter death rate in New York is that it can't possibly be very bad, because if it was, then there wouldn't be so many people in New York.
Which is a more dangerous location for children to play: a backyard swimming pool, or an interstate freeway? Well, many children die each year playing in swimming pools, and very few playing on interstate freeways. Therefore swimming pools are more dangerous. Do you see the obvious problem with this logic? The reason there aren't so many children dying while playing on interstate freeways is because there aren't so many children playing on interstate freeways. And the reason for that is because interstate freeways are so incredibly dangerous.
The death rate for interstate freeways looks pretty good, only because the population the death rate is measured among (adults in cars) includes none of the relevant vulnerable population. Because the relevant vulnerable population simply can't be found in any great numbers at that location. Because it's too dangerous.
Rich people are going to be fine anywhere. (Stockholm doesn’t get any increased mortality from the cold, no matter how cold it gets.) The relevant vulnerable population is poor people. Poor people simply can't be found in cold places because cold places kill poor people too reliably for a not-wealthy population to grow.
> The lowest recorded temperature in Kampala, Uganda was 12C (54F). Who’s dying from that?
Have you tried to live at 54F? Actually tried? It's really hard! That's why you don't have your thermostat set to 54F. It wouldn't kill *you*, because you're a wealthy First Worlder, but if you're so poor that survival isn't a given, "everything in life is harder" has a lot of knock-on effects.
Christopher Moss has details on some of the ways that people in cold places are using large amounts of wealth to adapt to the environment.
The part I take from it is that adaptations using wealth are more effective everywhere, and the main difference is that large poor populations that can't afford electric heating and must use open fires simply don't exist in cold places. Because populations without wealth cannot grow large in those places.
Thanks for pointing out this selection effect, which is obvious once you become aware of it. Entertainingly written as well.
It sort-of implies that if we could make Africa richer, Africans should be better able to deal with global warming (=increased hazard), since they will have more resources to adapt, so that the negative consequences of global warming (=vulnerability) diminish . (Risk = hazard x vulnerability again.)
Thank you, but the point I was trying to make was different. Figure there will always be someone left behind, for some definition of "left behind" (their lives are different from their ancestors', but not better). Those are the people who lack the wealth for the really good adaptations. The question is, what climate is least hostile?
I claim you can answer that question by looking at where most poor people were in fact living, say, a hundred years ago. Recently things get complicated by two problems: birth control, and people rising out of poverty. (Uh, I mean, that's a good thing, but it's a problem in the sense that it decouples population from the hostility of the environment. Efforts to lift people out of poverty make the poor population shrink, not because the environment is getting worse, but because poor people are being converted into non-poor people.)
There's obviously a lot of noise in the data: some places have much smaller populations than other places with seemingly similar climates. But there's also an unmistakable pattern.
We could call that the real "minimum-mortality temperature", the kind we actually care about. But it's not like there's a spike at any particular temperature. Based purely on eyeballing with a vague idea of where most people were living, India had a large population in one of the hottest parts of the world, while most poor Chinese were not actually living in the hottest parts of China. What we really have is kind of a smear over the upper side of the temperature scale.
It's hard to say, at the upper end, when humans start failing-to-thrive due to too much heat. Obviously it has to happen at some point below the temperature of Venus. But given the amount of noise in the data, I wouldn't trust anything except a stark difference we can see with the naked eye. Like, clearly India is less hostile than Siberia. But I don't feel confident saying anything about hotter-than-India. There just aren't a lot of places with higher average temperature than the hot parts of India. (There are places with higher temperature extremes, but they're deserts, and deserts are obviously hostile for unrelated reasons.) Some parts of Africa were a little bit hotter than India, but the parts of Africa that were the same temperature as India also had smaller population, so..."unrelated regional variation". Similarly other places with the same temperature as China had smaller population. There's just too much noise.
Even if you can hunt up a few places on Earth where the problems of heat exceed the problems of cold (not obvious: even in places you think of as scorched deserts, people burn dung to keep warm for lack of any other fuel), it seems obvious that putting a warm coat on the Earth will be a good thing on most of the Earth and a basically-neutral thing even in most of the warmer parts. (If the increased temperature was due to increased insolation, that would cause problems of its own, and of course the fact that the warm coat is carbon dioxide might cause problems of its own, but the warm coat itself seems like obviously a good thing.)
The claim is that Bressler and Heutel/Miller/Molitor and so forth are garbage-in-garbage-out because the numbers they're looking at aren't the numbers that matter. When you look at mortality rates, you're looking at populations that are large enough for you to measure mortality rates, so you're looking at people who do in fact live in the region and grew to large populations. To the extent that there are variations in current-year mortality rates, it's noise. The reliable numbers are the compounded mortality rates for *all the previous years*, which are baked into the population numbers, but more particularly the size of the population-without-wealth, though that's harder to measure.
I would also point out that this is fundamentally a problem of maximizing population. There's a certain population of people who lack the wealth to adapt well. A "pool of susceptible individuals" to use the Auliciems terminology.
By 2100, all of the current members of the pool of susceptible individuals are going to be dead, but we will have new susceptible. (Well, "we", won't, see above re: by 2100 everyone dead, but they'll exist.) We want to maximize the size of the pool of susceptible individuals...sort of. That number also shrinks when people rise out of poverty, which is obviously a good thing. But we want to maximize the population that they theoretically could grow to absent all the good reasons for that population to shrink.
When in Saudia, I had a long talk with a German organ-transplant-surgeon. He said the declared "causes" on "certificates of death" are a bad joke (at least in Germany): if one dies at home, a doc (usu. GP) takes a quick look and writes: sth. sth. heart-attack. Which thus ends up meaning: "no idea, really, but does not look like murder" (in hospitals they will usu. at least have a clue, what to suppose). "Cardiovascular" is the default diagnoses, without much if any value.
There might indeed be many, many more "flu-related"(as in "corona-related") deaths than the records show. Esp. among the frail.
Saudia (Kuwait): - death among "true" Saudis should not show much seasonal fluctuation - they spend 99% of the day in ac-cars, ac-houses, ac-offices, ac-malls. AC usu. put on max. power. (They may go out for a picnic in the cooler months, they do not use "crowded transport" all year). out I had to wear a jacket in office, it was just too cool without. South-Asian workers there (building!) at 50C in the scorching sun: sure, they should show higher mortality in summer. Statistics from this region need to be at least double-checked (90%+ of people in Qatar are not Kataris).
Last: DANKE! I wondered about this heat-cold-deaths for a long time, now I can wonder much more profoundly. - Why even with central heating a day in winter kills 40% more than a day in summer - yeah, one might think that is relevant enough to study till we know.
So basically the Winter-Death correlation is huge, but not empirically related to temperature itself. I suppose someone needs to come at it sideways by crunching data on non-temperature variables to try to tease out their separate effects. For example, randomly:
2. How does altitude affect the winter-death connection? For example, you could hold geographical region constant while comparing temperature fluctuation if you compared the winter death rates in tropical African areas with colder high-altitude locations nearby (does anyone live on Mt. Kilimanjaro?) Do high-altitude, low latitude death rates correlate more with geographical region or places with similar temperature fluctuation?
3. Do hours of light and dark separately correlate with death rates? Are there seasonal fluctuations in hormones, Vitamin D production, sleep patterns, etc. that could be explanatory?
If someone really cracks this extremely non-trivial issue you've identified it might be a Nobel-worthy event.
For present purposes, as the season when death rates spike, per Scott's article. I can't remember if he referenced what happens to death rates in the Southern Hemisphere. But I believe their flu season and death rate spikes are during "their winter."
Oops, now I see you were referencing Quito in particular (meant to say Ecuador not Peru, btw). But that's the whole point of looking at the data - what will it show for a place that literally doesn't have any seasonal variation in temperature and light. (Although rainfall apparently differs).
According to Wikipedia: "There are two seasons in the city: dry and wet. The dry season runs from June to September and the wet season is from October to May."
There are a number of comments speculating that different populations may have different genetic adaptations to environmental conditions.
No need to speculate.
I recommend this review: "The Genomics of Human Local Adaptation", Jasmin S. Rees et al, Trends in Genetics, June 2020.
There are lots of excellent references within the paper that people can then follow up on.
Here's the abstract:
"Modern humans inhabit a variety of environments and are exposed to a plethora of selective pressures, leading to multiple genetic adaptations to local environmental conditions. These include adaptations to climate, UV exposure, disease, diet, altitude, or cultural practice and have generated important genetic and phenotypic differences amongst populations.
In recent years, new methods to identify the genomic signatures of natural selection underlying these adaptations, combined with novel types of genetic data (e.g., ancient DNA), have provided unprecedented insights into the origin of adaptive alleles and the modes of adaptation. As a result, numerous instances of local adaptation have been identified in humans.
Here, we review the most exciting recent developments and discuss, in our view, the future of this field."
>But then why don’t we see any effect from excess winter heart attacks in very cold places like Stockholm or Siberia? Overall I’m not convinced of this one either.
Selection? This would be extremely interesting to study (genetically or epigenetically).
It's not the cold - it is the UV light that is missing in winter.
A whole host of physiological processes are dependent on UV light, vitamin D synthesis being the best known. But also nitrous oxide synthesis, lots of weird immunology and neurology are affected.
All the studies looking at excess winter deaths are the same as the ones looking at increased mortality from low vitamin D - they are measuring a surrogate for low UV exposure.
As a result, I expect global warming to be a net benefit as less clothing will being worn, hence elevated UV exposure.
Forgive me if this has been covered in the many, many comments below, but:
My understanding as to why flu is more prevalent in colder weather is that 1) sunlight kills germs, and there’s less sunlight (and people go outside less, which is perhaps the more important factor) in the winter, and 2) viruses don’t like humidity (for reasons I don’t quite understand). These at least seem to be the popular theories, and I would think that they at least deserve a mention, if only to dismiss them.
On a separate note, I’ve gone from “global warming will decrease cold deaths less than it will increase heat deaths” to “I’ve heard that that’s not true, and so now I don’t know,” to, now that I’ve read this article, “it looks like cold and heat deaths are mostly about human adaptation or lack thereof, so there’s no real way to tell what the effect will be—probably very little, but, as always, worse in poorer areas."
Ah, it was a slip of the pen? (I would not have been surprised if you held the opposite prior, since it is rather common to assume that global warming will cause more deaths than it saves - including in the article Scott links to ("Discussion" section). That's from all effects combined, though.)
I make no predictions on all effects combined, though it’s certainly plausible that it will cost more lives than it saves. But yes, my original belief, years ago, was that due to the prevalence of cold deaths, that it would—on this front—be a net benefit.
I would not be surprised if your last statement may turn out to hold also in the general case: "it looks like positive and negative effects of global warming are mostly about human adaptation or lack thereof, so there’s no real way to tell what the effect will be—probably very little, but, as always, worse in poorer areas."
>The lowest recorded temperature in Kampala, Uganda was 12C (54F). Most years it doesn’t even get that low! Who’s dying from that?
Ok so it's clear you haven't been to Kampala in the winter, because 12C when it's usually >35 is absolutely freezing. The people in Kampala are certainly all wearing mittens and fur coats when it's 12C; I spent a couple of months in a similar place and if it reached 12C that was bad. Not only that, but 12C without heating at night is even worse. If you don't have super warm blankets and try to sleep in an unheated house as 12C you will certainly get sick. Add to that the fact that if it's 12C at night it might still be 35C in the day a few weeks later. The sudden temperature swings are what people say triggers the flu wave; not sure if true but certainly seemed plausible.
Edit: ok so apparently Kampala doesn't actually get hot, my comment applies to places that are usually hotter. I can confirm from my own experience that 12C feels absolutely freezing if it's usually warmer.
I know it's probably impossible to measure well, but whenever I see something like this, I always wish that we could get a measure of QALYs rather than deaths.
Because if it's like 'these terminally-ill bed-ridden 90+ year-olds are going to die from something in the next year or two, and it turned out to be becaus their hospice nurse was 20 minutes late because of snow on the road', then my reaction to that is very different from 'healthy people in the prime of their lives get freak heart attacks from constricted blood vessels when otherwise they would have lived another 50 healthy years'.
> I find this suspicious, and I wonder if there are a bunch of less obvious seasonal viruses going around causing deaths that don’t get recorded as “seasonal viruses”. Or: we know that sometimes people can get strokes and heart attacks as complications of the flu - maybe we don’t notice the flu, or coroners don’t record it, and it just gets marked as a stroke or heart attack.
I had exactly this discussion with my partner who is a doctor. I had been speculating that our increasing understanding of COVID complications like strokes, clotting, heart attacks, etc. likely indicates that there are all sorts of complications with other common illnesses that we never studied deeply enough noticed before, and so we may have underestimated those numbers for years. Comparing like vs. like against COVID will be a shifting game for years if this is true.
Unfortunately this will also probably be used as justification by both sides of the lockdown debate.
I think you are on to something with extreme weather, as it is experienced locally, being the culprit. We had a bad heat wave in Oregon recently and a lot of older people died. It was even worse in British Columbia.
It wasn't the old people who needed to be cared for by other people who died. The victims tended to be independent old people who lived alone. My mother is really old, but she grew up in the tropics and rolled her eyes at me when I gave her advice about how to keep cool. She was fine even without air conditioning.
It was pretty hot, but I doubt if comparable heat in the Deep South would have had the same impact. A lot of the harm of extreme weather is going to fall on frail people who don't know how to cope. A young, fit person can deal with stress that will kill an old person. It will suck for them, but they'll live. Old people don't have the same margin of error, and if they don't have the experience to deal with the weather event they are far more likely to die.
There are a lot of simple things that people do every day that are taken for granted, but in aggregate they matter a lot. I think many lives could be saved by educating people who have narrow margins for survival how to survive rare events.
As for winter being a problem in tropical countries... I'm not sure about the flu being the culprit. What's the weather like during winter? Does it rain more? Does it flood? I'm with you on the temperature not being the cause but correlating with something else going on.
That excess winter death graph you have is interesting. The Netherlands, Belgium and France are right next to each other, but their data points are very far apart. Half of Belgium is Dutch, the other half is French, so IDK what the hell is going on.
Can somebody explain what the "minimum monthly temperature" means in the plot? Because I'm from Portugal and I'm sure it gets well below 10C there in the Winter...
One possibility is that people choose to rest during periods of "aberrant" temperature (heat in the tropical regions, cold in the cold regions). While you are resting (sleeping, siesta, whatever) at home, you are LESS likely to die.
So, the actual effect may be that cold death rates in sub Saharan Africa are "normal" and heats results in lower than "norm" death dur to lack of exertion. The opposite with heat in the cold regions.
This is a good point. The relevant vulnerable population is not just poor people, but poor people who are physically active right this moment. (Physical activity decreases mortality over the long term in rich sedentary populations, but in any populations it increases mortality in the short term.)
I still think by far the biggest effect at work here is that certain kinds of people simply fail to live in certain hostile environments in the first place, but it is also true that when you zoom in to a day-by-day basis, the population of "physically active poor people" decreases on particularly hostile days. (Not to zero; there are always exceptions like Arabian skyscrapers on tight schedules. But there are fewer people active, and fewer active people means fewer deaths.)
Maybe influenza (and other seasonal viruses) are cyclical by nature (evolution/mutation load in ARN viruses together with group immunity can lead to that, in a typical cyclic predator/prey dynamic), so a rather weak and local periodic signal (winter in the more densely populated regions for example) will act as a sychronizing clock to the inherently non-linear cyclical epidemy. This signal can be weak, with period variation, even skip a beat from time to time, while the response stay strong with a more stable period than the trigger...
This is also a postulated mechanism for global climate periodic variation (glaciation, oceanic cyclic oscillations), and quite a convincing argument on how relatively stable periodic phenomenon occurs seemingly out of nowhere...
Surely it's all the indirect reasons that are most accountable. From what I understand, 'crop yield down -> guy somewhat poorer -> more stressed and heart attack' would also get captured by their function.
Yeah in a way it seems to say that "people die less under usual conditions, more under abnormal conditions". I have the feeling we could do the same with a bunch of other variables and you'd always end up with the minimum of mortality around the "usual" value of the variable for the region.
- The estimations of the number of deaths due to Climate Change are dominated by deaths due to malaria and famines, both of which seem preventable by non-climate-related methods, i.e. better treatments for malaria (which are being worked on) and either some economic or humanitarian measures to mitigate the effects of localized droughts.
- Even if you consider the deaths from hypothermia alone (which are definitely cold-related -- it's there in the name), you'll end up with at the very least 50000 death per year, probably more, which is higher than the number of deaths from heat.
- That said, it is not clear how climate change will affect hypothermia, because deaths from it occur during unusual cold spells, and their frequency and severity may actually be increased due to climate change, because it increases the variance in weather events.
So there’s a clear hypothesis why warmer places have higher winter mortality; they get a similar variation in UV light, plus the warmth is good for bacterial and viral growth and survival.
I mean, too much sun ain't great for us either! Per NOAA, that Philadelphia reference amount of sun will (on average) give a white person without a tan erythema (a burn) in 14.5 minutes. In Hawaii it's 13 minutes and 23 minutes on Nunivak Island, Alaska.
Acute exposure with tanning acclimation is particularly bad for people, although a tan still only gives limited protection - but seems to be at an efficient point with respect to all kinds of skin cancer for people who are chronically outside. The people who are most at risk are office workers who then go to the beach in the summer without any tan. (For best results, begin in the early spring and slowly and carefully build up a tan. Getting a burn in order to tan quickly exposes you to the same cancer risks you're otherwise trying to avoid.)
So even ignoring all the health effects of the ozone hole that aren't directly radiation, our radiation tolerance advantage is probably most pronounced at relatively low UVA and UVB levels, and is minimal against UVC.
In spring 2020 my parents bought a lizard light; they put incoming mail and packages under it for a bit as a relatively human-safe covid precaution. I forget if it was in the spare bedroom or the foyer but it was a place where the mail was for much longer than people, compounding our dose-safety advantage over any hitchhiking viruses.
One possible (partial) explanation for the unintuitive effects is that a lot of the investment/infrastructure that reduces weather-related mortality-- heating, air conditioning, social norms that reduce time spent outside in poor conditions-- aren't really about mortality. They're about enjoying life and being comfortable. So sure, warm places might invest more in AC and maybe won't invest in good insulation and back-up heating systems. And as a result, they'll be more susceptible to mortality to cold than heat. But they weren't trying to equate the marginal cost of mortality prevention across hot and cold days... they were trying to equate the marginal cost of *enjoying life*. Growing up in a cold climate, the first even remotely warm day of May, my parents would take my brother and I to the lake and we'd exhaust ourselves swimming in the frigid water. Later, in college, that same warm May day would be an occasion for excessive binge drinking on our outdoor couch. Beach-going and alcohol are probably bad for maximizing life expectancy, but certainly good for something.
1. Deaths in tropical EU are practically not seasonal. Below is a chart I made for covid tracking reasons for Overseas Territories of France, the gray line is the average of weekly deaths in 2016-19.
2. Most of the studies I have seen uses daily average temperature. Maximum and minimum may be more relevant. For example, without air conditioning a lot of people have trouble to have a good night’s sleep when the minimum is more than 24C.
3. Climate/weather is more than temperature: for example, weather fronts are known to have large health effects, and weather fronts can be seasonal. Also, wet bulb temperature can be very different from actual temperature.
4. There can be a lagged effect of cold/hot weather, with some kind of accumulated damage/depleted resources (vitamin D, other vitamins etc.). The post mentions it, but it can be even longer lasting than just the extreme weather spell (there could be a decline throughout winter).
5. The ultimate question is whether apart from seasonality, overall mortality is lower in places with “better” climate (this may be difficult to define). There are many confounding factors, income, smoking etc., but within the EU at least, there is some evidence that the further South a location is, the higher is life expectancy (there is data for NUTS2 regions). The Madrid region has the highest life expectancy amongst EU regions. Corsica, Caribbean islands of France are pretty well placed too. In the detailed data though, as far as I remember, this results mainly from lower cardiovascular and cancer deaths – it would be a very important area to study.
6. There is a large difference between life expectancy of US regions and EU regions (latter is typically higher), if anyone has studies that compare seasonality, please link it here (i.e. is it mainly excess winter deaths, or is it higher all year around).
I agree that understanding lagged effects is really important and somewhat missing in the current lit. For one-- they would give a much better picture of how much of this is just temporally shifting deaths vs new deaths. Plus, it would help understand climate characteristics that lead to better or worse health, even if the death is ultimately attributed to a non-weather cause.
> Why would cold places adapt so hard that they did better than warm places? I don’t know, but this is what everybody says.
> I still don’t really get why cold cities over-adapt and end up with even lower mortality than the warm ones.
(I'm confused by the overall picture too.)
That's probably because many of these adaptations are discrete, not continuous. There's a certain cost in turning the heating slightly up or down (which is continuous), but the main cost is setting up the infrastructure. If you have 80% of the pipes needed for central heating to work, you don't have 80% of the heating, you just get a plumbing mess.
Are we dismissing the idea that temperatures that seem moderate to you are highly uncomfortable for people born in a different area? -- so I imagine the people are adapted to that temperature, and they function less well in other areas. There's long term and short term adjustment -- apparently stuff like the number of sweat glands you have is calibrated based on how hot it is for your mother when you're in the womb; other stuff is multi-generational adjustment.
But anyways, just anecdotally, I know people from much colder climates and much hotter climates who self report as being less comfortable and less healthy whatever they do. Even if you cover up, you're still having to breathe in a lot of cold air all the time if you're from a culture where covering your face is weird (or maybe with covid, that taboo has been busted?); but it's self-reported so who knows.
Separate question: how do we deal with the issue that death is inevitable when looking at these numbers? I've always wondered about the fact that presumably above a certain age, when death is inevitably just around the corner and you only need to make a mistake -- if causes of death are zero sum: reducing the number of deaths from falling down the stairs has to be balanced by deaths from some other source, because it's inevitable -- modulo extending someone's life by a year. I guess this is why people focus on deaths to youngish people?
If you are a stranger in Florida on an epic hot / humid day you are surrounded by people who are experts in surviving that climate with the necessary infrastructure to survive. If you show up on a very rare epic cold day you surrounded by idiots who don't have a clue what to do.
> The lowest recorded temperature in Kampala, Uganda was 12C (54F). Most years it doesn’t even get that low! Who’s dying from that?
Try being in that temperature without proper clothes. I am pretty sure that it is enough.
I was sleeping in test 12 C with clothes for 16 C and it was miserable. I would not be surprised by frail person with clothes for 26 C dying.
And poor weather to that like rain or wind and lack of high quality tent and add illness/malnutrition on top of that. And I would be even less surprised.
Many years ago I remember (anecdote alert) that the radio news reported that missing persons were often found dead in the countryside, and to have died from 'exposure'.
It's quite possible that people who are warm in the day through activity, climate, or shelter nonethe less die of 'cold' or 'exposure' overnight because of the reduced activity and shelter even if the temperature is not absolutely cold in temperature terms. I imagine that people in Africa might find the nights lethally cool if there was no cloud cover or shelter.
In extremely poor regions of South America and Africa, it happens that people die in winter during sleep because they use charcoal for heating and get suffocated.
If HxNy were the only flu strain, we would approach herd immunity within several years, even through a cold winter. So the flu continues to mutate into different strains to evade immunity, and one of the major unmentioned factors here is this strain churn, means a (in reality, a set of dozens of) different strains circulates through populations each year. The consistent cyclicality of flu season is largely driven by strain churn, but that still doesn't explain the peak/trough and their correlation to seasons.
I'd speculate summer as the selection bottleneck in highly seasonal regions, and winter as the exponential part of infection S-curve of a novel infectious agent. So: it's summer is northern Eurasia, and the living is easy, except for the immuno-compromised. Which strain is best able to make it through the summer? This is largely driven by which strain does the immune system have the least memory of. And since the immuno-compromised are usually old, this is perfect for finding something most other people have never been exposed to either.
Now it's September, and the flu has faced a 99% mass extinction event - especially around the previous year's strain where R0 is approaching less than one. Whichever funky new (so old, it's new) strain was able to hang on and continue to infect is going to well poised to spread through the rest of the population. Through travel, hajj's, agrarian laborers etc, these selected for strains again move throughout the world causing another peak. Immunity to the new strain builds, and then we do the summer selection process all over again.
"We still don’t really understand why the flu is seasonal."
Is anyone looking into migratory bird patterns? I'm surprised that the Wiki article didn't even mention those as relevant.
Waterfowl like ducks are reservoirs for influenza strains and migratory birds are known to be important to influenza's evolution and spread.
"Virologic surveillance of apparently healthy birds has established that the waterfowl of the world are the natural reservoirs of all known influenza A viruses. The Anseriformes (waterfowl) and Charadriiformes (shorebirds and gulls) are the major reservoirs in which the 16 HA and nine NA subtypes are perpetuated"
A common chain of transmission is that a virus will spread from migratory birds to farm-birds like ducks to farm birds like chickens sometimes passing through pigs and finally to humans.
It seems notable that the % overall excess death ratio reported in the Zhao et al. study throws up the most extreme and counterintuitive results in areas where the study's data is very poor and the temperatures are very extreme. It looks like they only had daily time-series data on mortality for 43 countries and extrapolated their mortality rates for all other areas based on factors like GDP/capita and daily temperature ranges. Some areas in sub-Saharan Africa and central Asia have extrapolated excess death rates (for counterintuitive causes of death) as high as 20-25%, which is WILD, and these areas seem to correspond with a) a lack of daily time-series mortality data for that location b) low GDP/capita and c) extreme local temperatures. It's possible that these simply ARE the conditions under which extreme counterintuitive mortality rate increases occur, but it feels much more like a model being left to its own devices and getting a little wibbly around the edges when the data is spotty.
(It's also worth noting that the scales on the map of annual average heat related deaths in Fig. 3 look suspiciously data-crime-y, but that's more of a procedural quibble than a criticism of the article. I bring it up here because without paying attention to the scales of the graphs it looks deceptively like the rate of heat related deaths for Europe [where there data is good] is very high.)
I find myself mulling over whether there is any correlation between the average wealth of a culture, and the rate of deaths related to either extreme cold or extreme heat. But I also am trying to figure out how pre-industrial cultures and civilizations dealt with extreme weather.
Do we have good data for deaths due to extreme weather among the Dorset people, or Icelandic settlers, in Greenland 1000 years ago? Between the two groups of people, I would suspect that the Icelandic culture was slightly wealthier. Did this affect survival rates during the transition from Medieval Warm Period to Little Ice Age?
What about the Thule people, who replaced both groups in Greenland? Were they wealthier, or not?
If any of these three groups had a better ability to survive in climatic extremes, it was more a product of culturally-learned behavior than of genetics or economic success.
I suspect that this pattern shows up in many of the examples cited for deaths due to hypothermia during a cold snap in warm climates, or deaths due to heat stroke in a cold climate. If the problem hasn't shown up often enough to generate a cultural story of what not to do in that scenario, then the likelihood of a person choosing to do something foolish increases.
The wealth of a culture can put a layer of protection around a person. It can reduce the need for the transmission of cultural knowledge. In some cultures, it was the knowledge about how to keep warm sleeping on the ground. In other cultures, it was the knowledge about how to keep cool when the temperature stays hot all day and night for many weeks on end.
Sorry, I didn't read all the comments, and certainly someone else mentioned this - so apologies to them, but I think you're looking at this the wrong way. You finally touch on this at the end of the article, but you use the word "because" as it relates to death which I believe has distorted your thinking. People don't die "because" of the flu, the heat, the cold, etc. People die. (hard period). However people die * sooner than we might like * "because" of the heat, cold, etc. So, the only stat that makes sense and what you need to look at is Years of Life Lost (YLL), or better yet Years of Quality Life Lost. Deaths will go up short term during the cold and heat, but a careful analysis should (perhaps) look at the annual death rates and see if during a year with higher than average temperature in a region the annual death rate has increased. I'm not saying it's not a tragedy when a certain percentage of the population dies 6 months sooner than they normally might, but that doesn't have the same implication as "10% of all deaths are due to cold".
One problem with "hot cities have worse life expectancy" is that hot cities also have lower income and otherwise differ demographically.
If you look at North America and Europe, the most affluent countries are in the north, and the poorest are in the south. Moreover, further north in the US, there are generally fewer black people on average, and more Asians, and blacks have higher mortality rates than whites do while Asians have lower mortality rates and live longer.
Hawaii - a tropical state with very few black people, but enormous numbers of Asians - has the highest life expectancy of any state. California, which has a lot of Asians and Hispanics (both of which have above-white life expectancy in the US) has the second highest life expectancy, despite being a hotter state. Indeed, the US north/south cline is mostly because of the South, which is also extremely obese, which is likely another significant driver of the trend.
As such, this really seems likely to be a "richer places live longer" thing... which makes the trendline completely worthless. The rich places that are pretty hot - like Hong Kong and Singapore - have quite long life expectancy, and Australia, which is also a pretty hot country, also has a good life expectancy. These "abnormalities" are simply the result of there not being many developed regions in hotter areas of the world.
And with regards to mortality rate increasing over the 21st century, this is goin to happen regardless of global warming, because the population is getting older on average because people are having fewer kids. So it's kind of worthless to project that mortality rates are going to rise, because no matter what we do, they're going to go up simply because there will be a higher percentage of old people in the population, especially in developed countries.
Okay, simple correlation: more exposure to sunshine = higher serum Vitamin D3 levels. Countries that consume a lot of fish/fish oils will have consistently higher levels of Vitamin D3 during periods when the population has lower exposure to sunlight. Higher levels of Vitamin D3 provide higher levels of protection against diseases and blood clotting/strokes/heart attacks.
Lancet article says: https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00081-4/fulltext tl;dr: "Globally, 5 083 173 deaths were associated with non-optimal temperatures per year, 9·43% of all deaths were cold-related and 0·91% were heat-related). ... Eastern Europe had the highest heat-related excess death rate and Sub-Saharan Africa had the highest cold-related excess death rate. ... From 2000–03 to 2016–19, the global cold-related excess death ratio changed by −0·51 percentage points and the global heat-related excess death ratio increased by 0·21 percentage points, leading to a net reduction in the overall ratio." - Cheers, global warming for saving millions from premature death this century! Ahrrg, "millions" - so it's just statistics ... :(
>the excess winter heart attacks, which are a direct effect of cold weather.
Keep in mind that influenza increases heart attack risk. https://www.nejm.org/doi/full/10.1056/NEJMoa1702090?query=featured_home
Yeah, this is true and important. I should specify that some studies have found a direct effect of cold, which I think has to be heart attacks from vasoconstriction, and then probably there are other heart attacks from influenza.
Here in Michigan we get early warnings from the county health departments that shoveling snow is a huge cause of heart attacks, so you’re supposed to take frequent breaks and warm up to avoid the problems of exertion + cold air during heavy breathing + vasoconstriction.
Is it just that people are more likely to get heart attacks while they have the flu, or does having had the flu also increase the risk of heart attacks?
Is there an elevated risk immediately after a serious case of influenza, or does each case of influenza create an incrementally mounting risk of heart disease? The explanation I had previously heard is that inflammation caused by influenza causes progressive and irreparable damage to heart muscle.
My impression is that people are more likely to get heart attacks while they're sick with influenza, but I await further information.
I've witnessed the onset of only one hyperthermia fatality, a Czech journalist sent to Florida in mid-July to report on the Apollo 11 moon landing. Despite temperatures approaching 40 C and high humidity ,he dressed in a three piece black woolen suit. He collapsed near the end of a long tour of NASA's sprawling Cape Canaveral space center in a vehicle without air conditioning.
This is minor, but I think this part is backwards:
>Most people don’t clearly say that excess winter deaths are a combination of cold-related (from the flu) and season-related (from cardiovascular) deaths, even though something like this has to be true
Isn't the flu season related and cardiovascular deaths cold related?
Thanks. I've fixed this.
I don't really think pointing to influenza or other diseases in Africa does much to explain the data. After all, that just pushes the question back one stage: why is it that these flu deaths are concentrated in the winter? If it's because they are more common when the temperature is lower than wouldn't that also support a causal story? You might try and say it's about the worldwide increase in flu during the winter but that doesn't work as the southern hemisphere has winter when we have summer.
I'm going to suggest a different explanation. Maybe it's all just about extremes of temperature being associated with unusual weather conditions which are more likely to lead to things like crop failures (and all the downstream badness including more wild animals dying leading to more opportunities for death). I have to think a bit more about it but the graphs above estimating MMT make me suspect that this is all mostly seeing some kind of mathematical artifact (e.g. that the more extreme the temperature is on a day the more likely it will be to occur during an unusual weather year).
I find the theory that flu cases rise in the winter due to people spending more time indoors, in close proximity to each other pretty plausible.
But why would they spend more time indoors in really hot countries? I mean in the Sahara wouldn't you be outside more frequently during the winter and seek shelter in your shaded home more in the summer?
I mean why is it that people spend more time indoors in the winter? I presume it's because they have greater need for shelter in cold countries and if that was the same mechanism in rich countries then that would suggest a causal mechanism.
> I mean in the Sahara wouldn't you be outside more frequently during the winter and seek shelter in your shaded home more in the summer?
Could this be the mechanism behind the whole thing? The outdoors is a more dangerous place than your own home, and people go out more when the weather is nicer - which means the summer in St Petersburg but the winter in Nairobi.
Flu season is winter everywhere. That seems like it would need an explanation about people being indoors in winter and outdoors in summer, which is only true in half of places. I’ve heard other claims about humidity and air temperature and the longevity of infectious droplets, and claims about travel within the hemisphere during winter. None of it quite adds up.
I agree there is no single plausible explanation. I’m not convinced that half the world is more likely to be outdoors in winter.
Humidity is also an unlikely explanation because, obviously, humidity is higher or lower in the winter depending on where you're at.
The only explanation that makes sense to me: The majority of the world lives in cold to temperate climates where there is an actual winter. This leads to a global increase in flu prevalence starting in the winter in the Northern Hemisphere. We "Northerners" then travel around the world and spread it, but it takes time to spread in the warmer climes and so it doesn't hit peak spread until "winter" in the equatorial & global south. A reach I agree
The one point about humidity is that heated air has very low humidity. Air that is at 100% relative humidity at 10 degrees C is at 50% humidity if you heat it to 20 degrees C, and if it is 100% at 5 degrees C then it’s only 30% at 20 degrees C. It doesn’t need to get freezing for the indoor humidity to drop considerably, though it does need to be temperate enough for indoor air to be heated.
The part where you say “this leads to” is the bit that needs explaining. Anyway the thought on humidity is that it’s lower (actual rather than relative) humidity that helps the virus. Humidity, as kenny explains, is lower in colder weather.
What about religious gatherings and holidays being more frequent and larger through the winter months? Notable exception being Ramadan which tends to happen in the summer. Is flu severity simply a matter of the frequency of mass and small gathering occasions increasing the spread?
Ramadan doesn't have a typical season - it is just every twelfth lunar month, and over the course of a decade or so, it rotates through the year and occurs in every season equally.
It definitely seems to me to be a plausible hypothesis that traditional gatherings are the source of the seasonal pattern rather than the weather. In the United States, it seems very plausible that cold/flu season begins in late November and December, and continues for a few weeks afterward, which lines up well with the biggest periods of family gatherings!
But if this is the explanation, then it would suggest that in China and Vietnam, the biggest cold/flu season should be February, and there wouldn't be notable flu activity in December/January. I'm not sure whether that's true.
There are even extreme cases like Saudi-Arabia in which people can't stay outside for a long time in summer. As far as I know, they stay in buildings pretty much all the time during summer.
But the flu season spikes in winter there, like everywhere else. Interestingly, it starts and peaks (Nov-Dec) a bit earlier than e.g. in Europe.
Unrelated, but also interesting from the same source: Fiji (southern hemisphere, close-ish to equator) has a wave either March/April or Jul-Sep, but "usually (only) a single wave per year".
Table 2 in https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0019515
That is weird. I notice that I am confused.
I don't know anything about culture in the Sahara, but I'd bet people gather more when the weather is at its coldest. If you're trying to beat the heat, you'd want to be alone in your shaded home.
You would spend time indoors, but also with good ventilation, at the very least with windows open, but possibly with fans or an HVAC system.
My hunch is that an HVAC system with bad filtration would be the worst of these, but I'm not sure how it would really shake out.
Flu isn't all that seasonal in the Sahara. In Africa, influenza is seasonal along the Mediterranean coast and in the southern countries, year-round in the desert and the tropics.
That's quite consistent with cold = indoors = more flu, and so less cold = less flu = less death, supporting the naive interpretation that we want to make the world at least a little bit warmer if we want to minimize death.
But if this logic truly holds, I'd also expect that in places that are hot and rich, warm = indoors because air conditioning = more flu, so that's something to look into. More generally, we have to actually understand why influenza is seasonal in temperate climates before we say that cold's got nothing to do with it and marginal warming would be a net harm.
The problem with this explanation is that it's not specific to the flu; if that's what it was, all contagious diseases would be winter-seasonal, but in fact, different diseases have different seasonalities, and the reason isn't well-understood. See https://www.sciencemag.org/news/2020/03/why-do-dozens-diseases-wax-and-wane-seasons-and-will-covid-19 for an overview.
Your extreme temperature theory doesn't explain why it's seasonal. As I understand it, mortality goes up every year in winter in hot places, and every year in summer in cold places. That doesn't line up with people starving because their crops had a bad year.
Do hot places have a winter?
Some do, some don't. Depends.
Singapore doesn't have a winter.
Most of them do have some sort of temperature variation, though, even if it doesn't correspond to the summer/winter dichotomy of the areas further from the Equator. Usually in tropical areas the rainy season is cooler because of greater cloud cover. Although it's not a big difference, Singapore does show slightly lower average daily temperatures in Nov-Jan (rainy season), daily mean a bit under 27C, than the rest of the year (dry season), daily mean a bit over 28C.
Note that lack of temperature variation doesn't mean lack of seasonality - the change in humidity presumably has quite significant health consequences.
Many tropical parts of the world have wet seasons and dry seasons. E.g., the monsoon monsoon season arrives around the end of May or early June in India (e.g., the first ascent of Mt. Everest was on May 29, 1953 to make use of warm weather, light winds, and long days but also beat the heavy snows of the peak monsoon) and lasts into the first few days of October. But I don't believe all tropical rainy seasons are on the same schedule.
And I don't know when the starving season would be relative to the wet and dry seasons.
Influenza virus prefers cold temperatures and low humidity. It does not spread well in hot, moist weather even if everyone is inside with the AC blasting. Exactly why this is true is a matter of contention. The common cold doesn't care about heat or humidity.
> are a combination of cold-related (from the flu) and season-related (from cardiovascular)
Are these supposed to be swapped?
I believe that David D. Friedman has an explanation for "[w]hy would cold places adapt so hard that they did better than warm places?"
In short, I believe the explanation is that it does not make sense to invest in heat regulating equipment or insulation in temperate places (in his example, New Zealand), because they have high fixed costs. Accordingly, houses in New Zealand are very poorly heat regulated (and, although it does not get extremely cold in New Zealand, the houses are much colder than countries with more extreme temperatures). In contrast, to survive in certain places with more extreme temperatures, it makes sense to incur the fixed costs. Once those costs have been incurred (e.g., for insulation), the average cost of achieving the optimum temperature year round is low.
I seem to recall that David D Friedman had this written up somewhere, but I can no longer find it. Since I understand David reads this substack, hopefully he will be able to expand further (and apologies in advance for any incorrect summary).
https://econpapers.repec.org/article/ucpjpolec/v_3a95_3ay_3a1987_3ai_3a5_3ap_3a1089-97.htm or http://www.daviddfriedman.com/Academic/Cold_Houses/Cold_Houses.html
Thanks!
also nicely analogized here:
https://worthwhile.typepad.com/worthwhile_canadian_initi/2014/12/why-does-toronto-have-better-outdoor-ice-than-ottawa.html
That thing was noticed in The Idiot by Dostoevsky comparing indoor temperatures in Switzerland vs Russia
Still true in 2021, houses in California are generally colder in winter and have waaaay more drafts than those in Russia.
Came here to make this same point. If a place expects a winter low of 70, but a cold snap hits and suddenly it's 30, people are going to freeze to death by the thousands. Meanwhile, if you were expecting -40 and it caters to -80, your heating bill increases slightly and you get to tell your grandkids about the great cold snap of '21.
I wouldn't expect heat deaths to follow the same pattern, though: 50 to 90 sounds harmless, while 110 to 150 sounds disastrous.
There happened to be something like that in Texas back in February. We normally have winters in the 20s to 30s F at the coldest, but all of a sudden had snow as far south as Austin and nights below 0 F. Our power grid, for various reasons, wasn't prepared for such a cold freeze, and left a lot of people (my family included) without power for at least a couple days. I don't know off the top of my head how many actually wound up dying because of it, but lots of water pipes burst and the whole fiasco cost a lot to recover from
Just checked; looks like the most recent count is 210 deaths
https://www.fox4news.com/news/texas-february-2021-winter-storm-death-toll-up-to-210-35-in-north-texas
A very plausible Buzzfeed analysis puts the number of excess deaths around 700.
https://www.buzzfeednews.com/amphtml/peteraldhous/texas-winter-storm-power-outage-death-toll
Don't forget that not all of those people were on the Texas grid that went out. Some were on the Louisiana grid, etc. It is frustratingly hard to tease out.
Unlike Texas last February, northern Midwestern cities like Chicago routinely function at below zero temperatures, but Chicago's power grid was knocked around badly when the heat hit 106 in 1995, a routine temperature in inland Texas.
Without bothering to look I'm going to guess that Chicago relies on a lot of natural gas for heat.
Yes, most of the upper midwest does. It also helps that Chicago-ish area is a major gas pipeline hub.
One of effects was damage to CPU foundry located in Texas.
See https://www.tomshardware.com/news/samsungs-chip-fabs-in-texas-ordered-to-shut-down-due-to-power-shortage
Note
> Unplanned fab shutdowns can have long-lasting impacts; for instance, a thirty-minute power shutdown in 2018 at a Samsung fab destroyed 3% of the global supply of NAND.
(not researched how significant it turned out to be in the end but definitely not helped, it is typical that power outage means that everything being produced becomes worthless - and production time may reach month, so power outage can mean losing months of production)
Longer than a month. A good estimate is 1.8 days per mask layer. I would guess that high performance memory is 25-30 masks.
I'm surprised they didn't have on-site reserve generator capacity to prevent that; given the extreme expense of loss of power
Yeah, I'm aware of aluminium smelteries having their own dams for hydropower, and I don't think that they would suffer nearly as much from power shortages !
I work in a die fab in the US. We do have generators, as well as various mitigation strategies.
These only work, however, if we are in the position where they can be immediately put into play - which basically means they're already turned on when the power goes out. (We also do things like avoid running too much product when it is extremely windy outside, precisely in order to minimize how much damage can happen from a power outage).
You can't just turn on your generation capacity *in response* to the power outage - it actually has to be on *beforehand*. Any sort of power interruption causes some of the particularly power hungry machines to be powered off briefly, which is a Problem because when they come back on, they can't just immediately resume what they're doing. I'm not sure if this is for safety reasons (you don't want your machine to immediately start ramping up to doing whatever dangerous thing caused an estop to be pressed, except it wasn't an estop, it was the actual power going out, but as far as the machine was concerned, the power was cut) or if it is just poor programming, but it is what it is.
Some of it is also just the fact that these processes are so precise, so any small deviation will completely ruin everything because it is off by a micron and you're done. Even less sensitive processes - like singulation of die - can be messed up a bit by a power outage.
Also also, if the power goes out, oftentimes the power generation is for safety rather than saving the product - that is to say, they want to make sure that the LN tanks don't have a problem, that all the acid stays where it is supposed to, that nothing that can't cool off cools off and nothing that can't heat up heats up, making sure that your cleanroom fans are keeping your cleanroom from getting contaminated (as cleanroom contamination can ruin *everything*), etc.
Knowing stuff from my die fab, it takes like a month to process a wafer from start to finish. So 1/12th of the product for a year (about 8%) is going to be being in process at any given time. Some of that 3% that is ruined going to be from the product being wrecked by being in a sensitive process, and some of it will be because of delays caused by the power being out.
An unplanned half-hour power outage has much larger issues than just "Oh it is out for half an hour"; a lot of equipment needs to be reinitialized and tested after a power outage.
It is also worth noting that some stuff can't sit at certain steps for too long, so anything that is sitting around can potentially "spoil" so to speak.
So yeah, it's not that simple.
Oof - that's way more complicated than the data center my cube is on top of, where they can run on battery while the (large and many) generators spin up. (The battery rooms are Not Small, either.)
I have a friend who worked through the storm at Samsung. They had to scrap EVERYTHING, to the tune of billions of dollars. It took a few weeks to get things running again too, because pipes broke, equipment needed to be replaced, and supplies like chemicals needed to be replaced.
Single data point, but up in Canada air conditioning is fairly uncommon, because swelteringly hot summers (to the tune of 110+F) are equally uncommon. It could be the same effect: a heat wave hits and you have no way to cope with the excess heat, unlike in places where you expect that sort of thing regularly.
Be careful of proving too much. It's a good formalization of the idea "assuming all temperature adjustment is heating, equilibrium room temperature is independent of exterior temperature with the dependent variables of heating and insulation costs trading off directly". But extrapolating from there to what's covered in Scott's article deviates from that assumption: the asymmetry between heating and cooling costs means the equilibrium insulation solution will *very much* depend on exterior temperature in any location that ever needs to run an A/C.
(Does that asymmetry explain why MMT is so different in different in different countries? In short - no. There's still a few factors missing inexplicable by mean temperature alone.)
One data point - we ran an SF con in the winter (in Sweden) and had an English GoH, and one of the things he said was that he liked that he didn't have to feel as cold here.
I suspect that England is still pretty much in the mindset of "put another jumper on" rather than making the house insulated enough to be warm all through. The relatively recent switch away from coal heating probably meant that sealing the houses better was not a good idea (coal was pretty dusty).
Also: England is cool and wet during the winter, as opposed to Sweden which is much colder and relatively dry. Which may be a confounder to relating flu deaths to temperature alone - is there a humidity-related factor there as well?
I believe that cold, dry air indoors is the most favorable conditions for flu to spread. With high humidity, droplets gain weight and fall while with low humidity they turn into aerosols.
As far as I can tell England if the worst culture on earth for temperature regulation. They put up with separate hot and cold taps!
Where are you from? I still see this fairly regularly in the US (and not always just with really old fixtures).
I’ve lived nearby my entire life in the US (five years in Canada and one year in Australia) and have never seen this outside the UK!
I just saw this in Santa Barbara, CA, in an old one-bedroom bungalow, but considered it notably unusual
It's common in Ireland too, as might be expected.
Are we talking about two separate knobs (common in my experience in the U.S.), or two separate spouts (never seen it)?
Oh, if we are talking about two separate spouts then it is so uncommon in the U.S. that it didn't even occur to me. Good call if that's what we're talking about (I also have never seen it).
Separate spouts. I'm an American living in the UK. The plumbing here is ridiculous.
(Of course, it's this way for valid historical reasons, something to do with ensuring stale water doesn't backflow into the drinking water supply, if I remember right. Tom Scott did a video explaining it. It's still ridiculous.)
> Once those costs have been incurred (e.g., for insulation), the average cost of achieving the optimum temperature year round is low.
The annual cost of heating is still higher in cold places, but the marginal cost of heating the house to be (say) 1°C warmer is lower. So if people in cold and warm places have similar heat preferences and similar incomes, the temperature at which people keep (i.e. the temperature at which more heat is no longer worth the cost on the margin) is lower. (This was David's argument, approximately.)
Having lived in Italy with roommates, I can confirm. Homes often have thin walls, single-layer window panes, and frigging metal window frames. And I find the home temperatures they have in the winter very low. Whereas in Hungary, the norm is double-layer windows, and wooden or hollow plastic window frames.
Same experience between Moscow and Tokyo. Tokyo: flimsy walls, single-pane windows, heating often with just an AC on the wall. Moscow: thick walls, double-glazed windows practically everywhere (and double panes MINIMUM if it's and older building), district heating.
Another effect of this: you can bum it out in Tokyo, and there are tent camps filled with homeless under underpasses etc. A sudden cold snap might kill these folks. In Moscow it's impossible to live on the streets so nobody dies from -35C (even if it lasts for weeks). However, hot weather will kill some people without access to an AC, predominantly old.
You see something like this effect in the US. Often the electric systems that see their peak in the Winter tend to be in Florida and Texas. This is because in those places it does not make sense to invest in a separate natural gas heating system.
Instead they use heat pumps that are essentially air conditioners in reverse. But they only are effective on moderately but not extremely cold days. On extremely cold days those systems need to use backup resistance electric heating which is far less efficient. But overall it makes economic sense not to invest in a separate system given those regions experience so few cold days,
I was under the impression that reverse cycle air conditioners were about 4 times as efficient as converting electricity directly into heat (though I guess that assumes only a modest temperature differential); I'd assume house design plays a much larger role than the choice of heating system
It is much more efficient but it only works down to a certain temperature. After it get too cold the heat pump is not effective. So most heat pumps have a back up resistance system that can add additional heating on really cold days. Its because it is less efficient that really cold days in warm places tax the electric grid.
Presumably also a matter of less or no insulation for the houses.
God knows I've been colder in the winter in my poorly-insulated Bay Area house than I ever was indoors in Chicago, where they understand about insulation and adequate heating. We used to complain about the draftiness of our Bay Area house and my mother would say, "Well, at least it's ventilating out all the radon." Thanks, Ma. Now where's the afghan?
After reading this post I immediately ctrl + F:d "David Friedman" to look for this comment. I'd read Friedman's piece on temperature regulation in Chicago homes vs California homes something like 10 years ago and my mind went there immediately. Strange how memories work.
Wait, no, isn't there a *really* simply explanation here. Generate some random data. It will always have some minimum mortality associated temperature. If you then call the increases in death relative to that MMT that occur at higher temperatures heat related and those at lower temperatures cold related you'll find alot of heat and cold related deaths.
I agree this doesn't quite explain the asymmetry between hot and cold temperatures but I'm going to guess it's something simple about the fact that plants are grown during the hottest part of the year leaving the coldest part of the year more time to do things like fight wars or when shortages are more likely to push people into lower immune activity or making more dangerous choices.
If you look at the graphs, it doesn't look like random data, it looks like a pretty smooth J-shaped curve.
I do see a number of S shaped ones as well but many do have this pattern I grant. But couldn't this just be regression to the mean? If you only have a very few days with very high or low temperature that will tend to be yield a more extreme average than if you average a huge number of days with a common temperature.
Also, they don't really say what the actual graphs represent. Based on what they are doing it sounds like it's something they predict by fitting a 21 day lagged thing with B-splines....wouldn't surprise me if this introduced some statistical artifacts.
The regression to the mean thing might predict extreme death rates at extreme temperatures, but it wouldn't predict that the anomaly would always be an increase, which is what is observed here.
I definitely feel there's room for it to be some correlated third variable, like eg storms, but the plots don't seem consistent with statistical noise
Scratch that, I hadn't read your other comments - I thought the include plots were death rate on days with that temperature, and even if their extrapolations wrt global warming are based on weird models the status quo would still require explanation. If the curves excerpted here are the heavily processed model rather than the raw data, though, all bets are off
I'm having trouble going through their math because, even as a mathematician, it seems annoyingly complicated. I will point to this fact which *might* be how they are drawing their curves:
"Specifically, we modelled the exposure-response curve with a quadratic B-spline with three internal knots placed at the 10th, 75th, and 90th percentiles "
If so, a quadratic B-spline is just a bunch of quadratics slapped together piecewise and, unsurprisingly, quadratics tend to go off to plus or minus infinity.
But these graphs seem to be more about the RR which they claim to derive from semi-Poission regression. But there are just so many ways you could end up introducing this kind of thing as an artifact in such a complex analysis I'm still betting on artifact.
I haven't thought this through, but why is there a knot at the 75th percentile? That seems highly suspect in conjunction with the "MMT is always near 80th percentile" thing...
So I went in and figured out how they are doing the lag time and it's even more worrying in terms of creating artifacts.
What they do is assume that an individuals overall risk of death on a given day is given by integrating some non-linear function of temperature over the past 21 days ( they point reader to this cite https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4098103/ ). But they don't tell us what non-linear function they assume but whatever they do the problem is that it's very likely to yield really weird predictions about the relative risk of the most extreme temprature days. When they fit the model they will be trying to minimize some kind of error and the fact that there are few of the most extreme temperature days will tend to mean that they get pushed to the most extreme values to balance out random fluctuations.
I'm not someone who runs regressions all the time so maybe I'm missing something but it seems like there is every reason to think that (in some way or another) the fact that there are few of the most extreme temperature days causes those days to tend toward extreme values.
I'm going to see if they will send me the R code and try feeding in some random values if I have time. If not someone else should try.
Another thing that could be causing artifacts here is the relative risk scale they are using. Towards the middle of the temperature distribution, there is probably enough mortality data so that the RR estimates don't deviate much from 1. At the extremes of the temperature distributions there will be less mortality data, and random fluctuations will generate more outliers. If there is no effect of temperature on mortality, you would expect equally many outliers with RR of 0.5 and with RR of 2. However, the mean of these outliers would be greater than 1. So I think it's possible that on the RR scale, the estimates of the mean can be biased upwards in regions with little data. Things might be looking differently on a log(RR) or log(odds ratio) scale.
I'm just speculating here, I didn't actually take a close look at the methods.
I have little to add aside from linking to my favorite flu-related paper, on the 9 conundrums of influenza
" (1) Why is influenza both seasonal and ubiquitous and where is the virus between epidemics? (2) Why are the epidemics so explosive?
(3) Why do they end so abruptly?
(4) What explains the frequent coincidental timing of epidemics in countries of similar latitude? (5) Why is the serial interval obscure?
(6) Why is the secondary attack rate so low?
(7) Why did epidemics in previous ages spread so rapidly, despite the lack of modern transport? (8) Why does experimental inoculation of seronegative humans fail to cause illness in all the volunteers?
(9) Why has influenza mortality of the aged not declined as their vaccination rates increased? "
The authors hypothesize Vitamin D levels and "Good infectors". Whole paper is worth a read though.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2279112/
Hopefully this past weird flu year will help people get answers! And hopefully next year isn’t an extra bad flu year because of missing immunity.
Given the summer RSV season we just went through I'm unfortunately somewhat pessimistic...I think travel bans and border closures particularly in southeast Asia plus a hefty dose of viral competition played a big part in the flu being so minor, and if people are expecting some cloth masks to get rid of flu season this year I think they are going to be disappointed. But I could be wrong! Time will tell.
Yeah, I'm not the expert but my friend the pediatric pulmonologist said about a month ago that even COVID aside, their (hospital) floor looked like a normal February.
This paper is fantastic, thanks. This really does help to explain the seasonality of the flu, and explicitly helps to explain why i.e. African populations might be more sensitive to seasonal variations in temperature when it comes to the flu.
It frustrates me a little that the messaging around covid at the moment is still "We don't know if it's seasonal", when it's been behaving exactly like a seasonal virus all this time.
I worry that the Northern Hemisphere is about to discover that even with a heavily vaccinated population, keeping Delta (or maybe Delta+) covid under control in the winter is a much harder job than keeping it under control in the summer.
I agree this is a really good bet, but I'm frustrated that we still don't know enough about seasonal viruses to even know what to look for (other than the obvious fact that it gets worse in one season).
Don't most viruses have reservoir species that they live in, in addition to humans? Could the seasonality of human infections have to do with either the life cycle of the virus in the reservoir species or the times of year the reservoir species interacts most often with us? I should note that I know basically nothing about viruses above a layman's level; I apologize if this has already been firmly refuted somewhere.
I'd imagine that animal-to-human transmissions are an extremely small fraction of all transmissions of viruses like the flu or colds (almost all transmissions being human-to-human), and thus animal reservoirs are unlikely to have a significant effect.
Polio did not have an animal reservoir (which is why we might be able to eliminate it) but it was strongly seasonal in august in the United States.
Just to add that the polio seasonality was because it spread via feces in swimming pools, and community pools were used in the summer.
Also, we've eliminated natural polio from the world. We're currently left with vaccine-derived polio in a few countries.
This is not true. Pakistan and Afghanistan both reported one wild polio case in 2021, which is almost certainly below the true number: https://en.wikipedia.org/wiki/Polio_eradication
Two total cases reported so far in the first ten months of this year? (https://polioeradication.org/polio-today/polio-now/this-week/)
Yep, a real epidemic you've got on your hands...
A big unknown is how well immunity (from previous infection or vaccination) will reduce the spread this winter. Jones, Stone, and Sulaeman [1] estimate that about 83% of Americans had antibodies to SARS-CoV-2 in May 2021. Presumably an even higher percentage will have antibodies by the start of winter. But on the other hand, there is evidence of waning immunity from the 2-dose Pfizer/BioNTech schedule [2]. And probably most of the general population won't have received a booster before the start of winter, especially given the FDA's inexcusable tardiness to approve boosters.
[1] https://jamanetwork.com/journals/jama/fullarticle/2784013
[2] https://www.nejm.org/doi/full/10.1056/NEJMc2113468
The FDA is slow to approve boosters for good reasons, it turns out. It's not tardiness. Arguably, they are actually starting to "wake up" from COVID-dreamland, and ask the sorts of hard questions regulators are meant to ask. For example, here are some of the issues with the Moderna booster trial:
1. No evidence of improvement in any actual clinical outcome. It doesn't stop infection, not even for a brief time: there was a 22% infection rate amongst trial participants. The presented argument for why the boosters "work" is that they trigger the production of antibodies. Yet medicines are supposed to achieve clinical outcomes, not merely change body chemistry. Even given this ridiculous success criteria, the pre-registered criteria for the trial was in fact NOT met. Moderna appear to have come up with an alternative criteria
2. Very small sample sizes in the trial.
3. Very unbalanced samples e.g. 60% of participants were women, virtually all were white, lower rate of obesity than normal, mean age was 53! They should be trialling this in the elderly but like before, generally aren't focused on those people.
4. They excluded participants with heart conditions, diabetes, etc, i.e. those who are perhaps most at risk from side effects yet who will certainly be told to take it if approved.
6. It's difficult to compare infection rates between vaccine and control arms because of how they present the data (the two arms weren't really identical), and the FDA was unable to independently confirm their analysis.
7. At the same dosage as before 28% of recipients needed medical attention! So they halved the dose, yet, even after that, side effect profile remains roughly the same as the prior round (or so they claim). More than half of people got headaches or fatigue, half got muscle or joint aches. It's not a pleasant process to get boosted.
Given that the boosters (a) don't improve anything anyone might actually care about and (b) are painful and unpleasant to take, I give it about 4 months before they're being mandated by governments and anyone who refuses is being demonized. TRUST THE SCIENCE!
>Yet medicines are supposed to achieve clinical outcomes, not merely change body chemistry.
Now just tell that to the people who approved aducanumab . . .
Yes, but there are a lot of people (actual scientist types, e.g. Derek Lowe) who are dunking on that approval.
Not so much with any of the COVID trials, vaccine or booster.
Whatever the fda is doing it’s not what you want. They didn’t complain about the data - they just took months to meet and then approved it when they did.
Does it at least prevent serious/severe COVID (ie. hospitalization)?
I'm not sure. That doesn't seem to be mentioned by the articles I read about it. Note that reduced hospitalizations wasn't something the original non-booster trials were looking for and wasn't a claimed benefit of the vaccines before effectiveness against infection collapsed. The claims vaccines reduce hospitalization are all based on seeing how many vaccinated people turn up in hospitals, I think. But there's a confounder there: everyone is being told that if you're vaccinated, you won't need to go to hospital, and a lot of hospitalization is driven by people choosing to go there.
I don't know if any study is able to control for that.
I don’t think “exactly like a seasonal virus” is right. The UK’s two highest case spikes so far were early January and mid-July. Last year we had a very mild September, this year cases have been quite high. There are a huge number of confounders (particularly the governmental restrictions) that make it hard to say what the behavior would be seasonally all things being equal. There does appear to be some seasonality to the data to my eye I don’t think it’s open and shut by any means.
My guess is it might be periodic but not exactly 'seasonal' in the sense of 'tied to a season'. Eyeballing the graph of new cases in our area, the waves have peaks/centers around 18 weeks apart (give or take a couple weeks), or about four and a half months.
This seems like one of those things that's "probably true but we can't prove it so we can't announce it" for disease experts.
Are there other viruses that have both a summer and winter season in the south, and just a winter season in the north? That’s the best guess on this right now, but with a total of two summers and one winter it’s hard to be confident.
As far as I understand it, the expectation of increased mortality at higher temperatures boils down to (no pun intended) the shape of the mortality curve at most cities. The rate of increase of mortality below the optimal temperature is gradual, while the rate of increase of mortality above the optimal temperature is steep. Assuming that the mortality vs temperature curve doesn't change over time (a big if), a given temperature increase causes a large increase in the heat-related mortality and a smaller decrease in the cold-related mortality.
Whatever the mechanism turns out to be, what a fascinatingly counter-intuitive pattern of data. I love this kind of stuff.
> One more thing: is all of this is mostly killing very frail people who are on the verge of death anyway?
A lot of people are asking the same question about Covid-19.
Why, has something changed in the last months leading to Covid stopping to kill or durably cripple significant amounts of even "healthy" individuals ?
COVID isn't just killing the elderly.
Additionally (and frankly, more problematically), it is causing significant disability in a significant fraction of victims. Roughly 1 in 10 COVID patients who had mild cases (i.e. no need for hospitalization) suffer from long term effects.
I have a friend who now suffers from asthma and chronic fatigue due to COVID. He never got super sick but he was coughing heavily for months and has to use inhalers now, and he feels exhausted after working for just four or five hours and often has trouble doing fun things because he's so tired.
This is honestly far worse than it killing elderly people, as it will have much larger negative societal ramifications.
In winter people have fewer fresh fruits and vegetables to eat (especially outside the first world). They also get less vitamin D from sunlight. Worse nutritional status in the population could weaken immune systems and slightly increase the r-factor of any virus. Plus cold helps the virus survive longer outside the body, and incentivizes people to gather indoors. The r-factor of the flu hovers near 1, so those small changes can make it go supercritical or subcritical seasonally. That's my best guess as to why the flu is seasonal.
But in general warmer areas have a higher disease burden due to vectors that can't thrive in colder climates. Warming will likely expand the territory of malaria, and I don't know if anyone is factoring that into their calculation of warming deaths. But maybe that will be moot if someone invents a good vaccine or a clever way to kill the insect vector. There's too much unpredictable human action between the warming and the final consequences to have high confidence in any number of deaths.
I'm not sure warming will expand the territory of malaria. Malaria used to be common in southern Europe and southern U.S.; it isn't anymore because of modern anti-mosquito efforts. It's become a mainly tropical disease because the tropics are poor.
I suppose there might be some place in Asia, currently protected by its climate, that won't be able to afford anti-mosquito measures.
Malaria used to be even prevalent in Germany.
Yes because we drained the swamps and everyone is now in a sealed airconditioned building.
Washington DC was a hardship post in the 19th century because of malaria among other things.
That's along lines I was thinking of. Even in Africa, I wouldn't be surprised if more food is available in summer than winter.
It's maybe worth considering that "winter" in sub-Saharan Africa (at least the part of West Africa which I am most familiar with, which admittedly does not actually have such high cold-related deaths) is more commonly referred to as "the dry season". It is definitely colder, and many people do have very poorly insulated houses; i.e. not even single-glass window panes, so that nighttime temperatures of 12°C can actually be dangerous for vulnerable people. However, the lack of food, and perhaps also poorer access to safe water and sanitation, may be bigger factors. If this is about food though, then things should get even worse in the "spring", i.e. when it is warmer and the rains have started but before any of the new crops can be harvested.
On the flip side, in the tropics the number of hours of sun is basically constant throughout the year so reduced levels of vitamin D are not a plausible explanation for increased flu incidence unless it is entirely due to people not going outside. Also, the dry season should have lower malaria risk, so whatever effect is causing excess winter mortality needs to be big enough to outweigh malaria.
Not sure if the dry season would have lower malaria risk. I think it would depend on just how much rain falls in the wet season. Since the mosquitos breed in standing water, if the rain causes everything to overflow you won't get more mosquitos until it dries up a little.
What about lower respiratory damage from indoor fires? I just read an article a couple of days ago saying that the high price of canned gas (propane-butane, I guess) is forcing many West African households back onto biomass fires for cooking--and, presumably, space heating or radiant heat.
Carbon monoxide in the one case, carbon monoxide and noxious particulates in the other. I don't know for how long gas cookers have been widespread, but if this matters the uptake pattern should correlate inversely with winter mortality in WA.
Hi will, just to pick on a small part of your argument. I don't think Vitamin D has been shown to be causally important in any disease not related to bone health. While there have been a lot of diseases that seem to be associated with Vitamin D deficiency, subsequent attempts to rigorously study if supplementing Vitamin D levels would help have all been disappointing (again outside of bone health) and not found an effect (please tell me if I'm wrong!).
I think a big reason for this is that people with low Vitamin D levels are generally pretty different from people with high vitamin D levels! People with low Vitamin D levels generally don't go outside and people with higher Vitamin D levels do. For literally any disease (maybe with the exception of skin cancer, which more on that in a second), if you asked, which group of people will have less of it/have better outcomes, those who go outside, or those who don't, you'd likely say the group who goes outside more is healthier.
In skin cancer, high vitamin D levels are associated with higher incidence! Does vitamin D cause skin cancer? Of course not! This association is confounded by exposure to sun. Likewise the relationship between vitamin D and COPD, Asthma, heart disease, cancer, and any of a number of other disease is likely confounded by going outside, which is a proxy for how active/social/otherwise robust someone is.
It turns our that exposure to the sun isn't just about vitamin D. Human have precursors under the skin for nitric acid, and they're activated by sunlight. (I don't know about sun lamps.)
Nitric acid helps regulate blood pressure.
Just for fun, it turns out that you can't find out about this by studying mice. Mice don't have the precursors under their skin, probably because they're covered with fur and prefer only going out around twilight and dawn.
How interesting. I wonder if sunblock inhibits that reaction?
Interesting. Yet another reason people who go outside are different from people who don't. Do you have a source for this? I'd love to read more.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5593895/
Not my original source which was from a humorous British scientist (doctor?) who spent some time in Australia and was getting teased about the high rates of cardiovascular disease in his home.
Cold weather probably causes people to go outside less and be less active, which is unhealthy. Vitamin D may or may not be in that causal chain, but either way we can say that cold weather makes people less healthy and thus more vulnerable to flu.
I have ulcerative colitis, and vitamin D is widely recommended to help with that. I've been taking it off and on for a decade. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4991203/
It is also widely recommended for rheumatoid arthritis and psoriasis https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4991203/
The above are all autoimmune conditions. Death from respiratory viruses can be sort of similar, in that the immune system causes so much inflammation in the lungs that it kills you. But so far the results of vitamin D on covid are sorta mixed and unclear.
A couple of weird thoughts:
-Presumably one way to die while hunting in Greenland involves ice not being as solid as you thought, which is more likely if it's warmer? Do Tibet and the Andes experience something similar with more avalanches or rock/mudslides?
-One group of people who are particularly vulnerable to the cold are the homeless. Is there a relation between homeless population and cold-weather deaths, and is this affected by things like emergency shelters that only open in unusually cold weather?
I have read that Inuit are falling through the ice a lot more than they used to. They figured out how to recognize thin ice centuries ago, but today's thin ice doesn't always look like it should.
Bummer.
I am fairly certain only hardcore traditional-minded Inuits still hunt on the ice, or hunt at all. It has become like Sami reindeering in Scandinavia - only a fraction of the Sami have anything to do with it.
Most Inuits live in cities, like most Sami do. (I would be surprised if this was different in, say, Canada, or everywhere really.)
I find the human ability to adapt to different temperatures fascinating, and I'm not sure I understand it well enough to dismiss the idea that people are dying at 60 degrees F out of hand.
My brothers and I all grew up in a temperate, almost Mediterranean environment: rare to get as hot as 100, rare to get as cold as 25. As an adult I moved to a place where the typical winter temperature is around 0, and in summer it doesn't reach 90. He moved to Mexico.
He visited me once in summer: it was 75-80 degrees the whole time he was here, and he spent the whole trip in a long sleeve jacket with a puffy vest on top. Because he was cold! It certainly wasn't a put on, his internal thermometer had just shifted upwards while mine had shifted down. A couple years ago we had a heat wave where it hit 88 degrees for a week: we were all miserable with the heat, even though I would have been fine with 88 before I moved up here. My younger brother is planning on moving to Sudan and has visited there before, in a region where the typical summer temperature is in the high 90s, low 100s. While he was living in Texas someone who had lived in South Sudan for a few years came to visit and talk to him about moving to Sudan, and that guy also wore a long sleeve jacket and puffy vest his whole visit. In Texas. In summer. He was genuinely cold.
I don't know how the body does it, but if someone can be genuinely cold in Texas in summer because they're used to hotter, isn't it possible that person might die of cold if it hits 50 degrees?
Assuming the people involved are naked overnight: 50* would kill a Eskimo. 70* would kill you. 90* won't kill anyone. Subjective temperatures are hilarious, but there are hard limits here.
*unsourced numbers pulled directly out of my ass.
Based on my Boy Scout experience, being cold enough to be miserable doesn't necessarily mean you're in danger, even when you're sleeping. (Of course none of us were old or vulnerable.)
Weren't your and your brother's temperature preferences different before you moved? Couldn't that have to do something with why you moved to a colder place, and him to a warmer one, in the first place?
As far as I could tell growing up we had the same temperature preferences: he loves Mexico because there isn't any pollen in the air, unlike where we grew up.
Blood concentrations of water and salt, and circulation to your skin, adjust to heat in 5-7 days according to an incredibly ad-heavy source- https://bikehike.org/how-to-acclimate-to-hot-weather/
Populations with generations of adjusting to hard labor in extreme heat, say Sub Sahara Africa, or extreme cold, say Greenland, might have trouble shifting gears in a sudden cold snap or heat wave.
I moved from Georgia to Ohio, and it took a lot longer than 5-7 days to adjust. My first winter here felt colder than later winters, even though it was actually milder.
I've never done any serious mountain climbing but I understand that teams set up a cold base-camp to acclimate themselves, and 5-7 days sounds about right for what they do.
And these are relatively young, prepared, nourished, healthy or even athletic people. If I was old, unprepared, unhealthy, and more 'warped by toil' than 'athletic', I'd be more likely to just kick the bucket.
It is possible to die of exposure at surprisingly high temperatures, adaptation or no - the most common temperatures at which people die of exposure are in the 30s-50s F, and it's possible to die of exposure even in temps as high as the 60s F. If you are wet and it's windy and 65F, hypothermia is a real risk.
https://www.nytimes.com/2007/01/09/health/09brody.html
It reminds me of an Ethopian girl I knew in the 80s who was on a temporary assignment to my place of work. In May we had some warm sunny days so of course we Irish were all wandering around in our shirts enjoying the unusual heat. But poor Mobete was still shivering in her wooly jumper!
After living in Phoenix for years, my comfort range is 82F to 113F (28C to 45C), at least given desert humidity. Below that range I'll put on a jacket; below 68F (20C) I have difficulty coping even with a thick jacket. In the article, Scott expressed shock at the idea of someone dying from the cold at 54F (12C), which to me just sounds like he's lived a long time in the Bay Area and Michigan and other places where that's a normal temperature.
Yeah, that's exactly the sort of thing I'm talking about. After living much closer to the arctic circle, 54F is short sleeves weather and 80+F is "It's too hot! I'm sweltering!" What I really want to know is how much of our ability to adapt to temperature is physical vs mental. If it's significantly physical than it's reasonable for 54 degrees to be fine for me and deadly for others.
No consideration of the possibility that all this weirdness has something to do with genetic differences between populations? Africans are adapted to one climate, Swedes another. You can speculate all day on what that means, but all we know is that genetics is probably conflating all of this somehow and we can’t know anything until we account for that.
I was wondering about this with regards to the cardiovascular deaths. If one population has mostly enzymes or vein structures or other factors that are tuned to work best in a particular temperature, it's plausible that going below that temperature could result in excess mortality for that population, even if it's not considered dangerous for the "typical" human. But then I also wondered, isn't temperature inside the body extremely tightly controlled? Just how consistent is internal body temperature a) in different environments and b) in different populations? c) the outer parts of the body near the skin vs say, the heart and lungs?
Just to indulge in one bit of speculation, much more of the world population will be of black African descent in the coming decades, whether they stay home or end up settling abroad. Therefore, this tilts things in the direction of a warmer world in which more people are adapted to the warmth, making global warming seem less bad.
I originally considered that Greenlanders, Tibetans, and Andean Indians are really the three groups that have the most evidence for cold-related adaptations (there are other people in cold areas, eg Canadians, but they're colonists). But it was hard to go from there to "dying of minimal amounts of heat", and again, it seems weird that they would over-adapt rather than correctly-adapt.
I think if there was some sort of evolved ideal temperature x actual temperature interaction, we would see more weird stuff in eg the US, where lots of people who evolved for eg England are stuck in eg Florida. But I think the US has a pretty similar pattern to Europe.
> But it was hard to go from there to "dying of minimal amounts of heat", and again, it seems weird that they would over-adapt rather than correctly-adapt.
This is one of those things where I wonder if they have adapted correctly to the 90% case, thus adding risk to the 10% case. In other words, at-risk people are comfortably adapted 90% of the time and under temperature-related physical stress 10% of the time, and that 10% of the time is when a disproportionate number of them die.
America used to have strong seasonal mortality patterns due to infectious diseases. In the South, whites died more in the summer, in the North, blacks died more in the winter. Tropical vs. respiratory disease rates had a lot to do with the demographics of the Union vs. Confederacy and the profitability of slave labor.
Nowadays, everyone dies more everywhere in the winter.
Do white people die more in winter in Africa?
There are some observable differences between populations in terms of temperature regulation, such as distribution and structure of body fat. This seems (confidence: likely but not settled fact) to be both a function of genetics and environmental adaptation.
For example: https://www.nih.gov/news-events/nih-research-matters/cool-temperature-alters-human-fat-metabolism
https://www.ucl.ac.uk/news/2018/may/gene-may-have-helped-humans-adapt-cold-climates
Population of large parts of America is from ancestors adapted to very different climates, same with Australia and New Zealand, and to a lesser extent everywhere with large scale migration. So unless there was extremely significant adaptation in the last couple hundred years it doesn't seem plausible
Aren't suicides seasonal? A quick search gives me Wikipedia saying they're much higher in spring and summer, though it sounds like it's about the season and not the temperature. Is this effect too small to be important?
Probably, I think suicides are around 1-2% of deaths.
The seasonality in the New York City chart is striking. It is always peaking around the end of year. I'm thinking what if the real cause is lack of daylight and sunshine and the cold temperature is just a correlation. It would make sense. People are miserable when it is always dark, they have poor imunity because of insufficient exercise insufficient vitamin D and bad mood, it could be good explanation for excess deaths. After all you are a psychiatrist, you know better.
End of year also is a time when people consider the state of their life. The obvious place to look to rule that out or in is the Southern Hemisphere where end of year is in summer.
As someone who's been depressed for ages, I'll say that I generally get worse in winter.
Good point, and I'd expect reduced daylight to also cause more accidents and more crime.
Not made better by the loss of daylight savings!!
They are quite seasonal - surprisingly consistent spring peak. However, that pattern is declining for some reason.
A quick bit of googling found that chilblains can show up at temperatures up to 16° C. No one is dying of hypothermia at that temperature, but that doesn't mean health can't be affected, especially if you don't have access to a source of artificial heat.
Could there be aspects of acclimation in addition to adaptation going on here?
My completely speculative take of the scatter plot you you show is that countries to the top-right, i.e. high-temperature high-death countries, look like they could have more homelessness than the ones on the bottom-left. Perhaps it is homeless and almost homelessness that is explaining part of the relation, but I doubt it is much.
I don't understand how the MMT chart for NYC (showing the highest mortality at high temperatures) fits with the NYT deaths-over-time chart (showing the most deaths in the winter). I didn't take the MMT charts to be some sort of adjusted-for-season death rate, it's just death rate vs temperature, right?
Temperatures near the high have the lowest mortality but temperatures at the high have the highest, while all temperatures near or at the low have elevated mortality.
I happen to suspect the whole thing is a weird statistical artifact of their analysis, but it could be consistent if all winter has elevated death, while most of summer is low death apart from a few spike days.
It appears that the answer to the question "will global warming cause fewer people to die from the cold?" is "no: it will in fact cause _more_ people to die from the cold".
This depends on whether the "death vs. temperature" distribution stays fixed as the distribution of temperatures moves up, but that naively seems unlikely to me given that "death vs. temperature" is already so highly variable across geography.
Also relevant: did the Grateful Dead prophesy in "New Speedway Boogie" that the end of the world would come with cold-related deaths in high temperatures?
> Now I don't know but I was told
> In the heat of the sun a man died of cold
> Do we keep on coming or stand and wait
> With the sun so dark and the hour so late?
Was riffling through Numerical Recipes in C and a copy of Petzold to gin up some splines.
Queuing up Working Mans Dead right now.
Jerry and the boys did a lot of their American Beauty and Working Mans Dead stuff at The Guthrie Theater in Mpls in October 1970.
I saw the second show. Not sure if they did NSB. Mainly remember them bringing down the house with a 20 minute cover of Dancing in the Streets. Damn. What a show.
One way or another...this darkness got to give.
More than half of all Americans die in an institutional setting: hospital, nursing home, or inpatient hospice. All home + road + other deaths combined are less than 50%. The temperature inside a hospital has very little correlation with outdoors temperature, yet we see this incredibly consistent temperature-mortality correlation throughout multiple US and world cities.
If there was a breakdown of temperature-mortality curves based on place of death, we'd have a fairly good idea of whether it has anything to do with temperature at all.
If the correlation was truly a direct causal effect (unusual temperature -> death) then we would see an extremely strong correlation for outdoors deaths, a moderate correlation for home deaths, and very little correlation for hospital deaths. On the other hand, if the correlation mostly reflects seasonal variations in infectious disease, risk taking behavior, diet, etc. then we would see very similar curves regardless of place of death, or even stronger mortality curves in hospice and nursing home settings where the populations have the highest susceptibility to infection.
If someone gets a fatal case of something temperature-related outdoors, but survives long enough to make it to the hospital, would that count as a hospital death?
Yes, so the "hospital" numbers wouldn't be entirely reflective of place of illness.
On the other hand, folks living in nursing homes or inpatient hospice generally get VERY few outdoors hours, and none when the weather is bad. So the temperature/death correlation for NH/Hospice place of death should reflect "not actually temperature causality".
I'm actually not entirely sure that's accurate. Even if a nursing home is perfectly temperature controlled (which I'm uncertain about - it has been a while since I've been in one but I don't recall my relatives feeling that way) there are second order effects at play here in cold weather vs. warm weather:
* Fewer family / friends visits as the weather makes it challenging = less social interaction which is significantly important / highly correlated with mortality
* Less outside time in the winter = less physical activity & less Vitamin D (even a small amount makes a big difference)
* More absenteeism & tardiness in the nursing staff = more unintended mistakes with medicines & care and less familiarity with specific needs of the patients
I could see all of those playing a major role - and honestly probably extend outside of nursing home environments in cold weather and have similar negative impacts across the board.
I think humidity would have something to do with it also.
If someone dies of influenza in a hospital or nursing home, then either an influenza virus spontaneously generated inside that institution, or someone managed to get the flu outside the institution and bring it in with them. So people will mostly die of influenza in hospitals, etc, at about the time people are getting sick from the flu outside them.
Here's a well-documented example of heat-related excess deaths: Worst heatwave of my 18 years in Chicago was five days in July 1995, where the temperature peaked at 106 and humidity was very high. The heat caused partial power outages so air conditioners were off at times and even iceboxes lost their ice.
Out of a population between 2.5 and 3.0 million, an estimated 739 more Chicagoans died that week than was normal. From Wikipedia:
"Eric Klinenberg, author of the 2002 book Heat Wave: A Social Autopsy of Disaster in Chicago, has noted that the map of heat-related deaths in Chicago mirrors the map of poverty.[2][7] Most of the heat wave victims were the elderly poor living in the heart of the city, who either had no working air conditioning or could not afford to turn it on. Many older citizens were also hesitant to open windows and doors at night for fear of crime. Elderly women, who may have been more socially engaged, were less vulnerable than elderly men. By contrast, during the heat waves of the 1930s, many residents slept outside in the parks or along the shore of Lake Michigan."
The city government didn't do a good job of responding with cooling shelters or public service messages to check on your aged relatives, although after the disaster they improved their response notably in subsequent heat waves.
https://en.wikipedia.org/wiki/1995_Chicago_heat_wave
In France in the 2003 heatwave 14,000 people died. I've heard that it is particularly the elderly who lose their sense of whether they are dehydrated and may not realize they are overheating. Normally their weather and house design allowed for natural cooling during the night but the heat wave was too hot through the night for that to happen https://en.wikipedia.org/wiki/2003_European_heat_wave#France
I suspect that cold deaths are more age variant as a general risk factor rather than a specific overheating event. It's interesting to have seen one study giving numbers that current warming has only reduced cold deaths twice as much as heat deaths have increased despite cold deaths being several times higher. It seems the cold is more typically a long gradual rise while the heat deaths graphs are exponential thus the balance shifts faster than I imagined
The great Moscow heatwave of 2010, blamed by Putin on secret American weather machines, seems to have killed over 11000, plus drownings and other accidents. Some deaths were due to worse air pollution.
https://pubmed.ncbi.nlm.nih.gov/24598414/
Moscow had another heatwave this summer, I believe. Data awaited.
Who dies of 12C weather & why very cold cities have fewer cold-related deaths than hot countries in Sub-Saharan Africa has everything to do with the simple fact that cold places tend to be rich and hot places tend to be poor, and poor people in hot places have exactly one way of dealing with cold weather they aren't used to -- they build fires.
Remember, we are talking about people too poor to own sweaters, or boots, or woolens of any kind. Their only shoes are sandals. They live in huts with zero insulation, because they are made for air flow in hot weather. And they often sleep outside, with thin sheets to serve as blankets, if any.
Under these circumstances, 12C or even 15C or 18C is absolute torture, especially when your body is not used to it. I grew up in a tropical country and despite almost 20 years in the US I am still miserable at any temperature below about 18C (65F). And I own all the winter paraphernalia I need!
So what do you do when it's a bitterly cold 17C and you have no way to keep warm? You build a fire, and try to keep it going all night. And you have no actual fireplace, or chimney. I wonder how many of these winter deaths in hot countries are actually a consequence of fire.
or Carbon Monoxide poisoning
Yes, relatedly.
Yeah that's absolutely plausible. Hurricanes in the US kill more people from carbon monoxide poisoning than from wind or water, so I can absolutely see cold waves in hot countries killing people because of unsafe heating practices.
Working in a Midwestern inpatient hospital in the winter, you'd also see an occasional carbon monoxide poisoning due to bad fireplaces, woodburning stoves, furnaces, etc.
Terrible problem for WWI tank crews too.
Shoveling snow off your driveway is a stereotypical way for a man to trigger a fatal heart attack.
I have no idea, however, how big of an effect that is.
That seems like it happened a lot more often 40 or 50 years ago. Not citing any published data here. Just my recollection of how people - men I guess - tend to buy the farm.
I think the decline in smoking among guys and just general awareness that being 55+ and out shape makes a sudden heavy exercise experience in cold weather risky.
If this is a broader trend I would wonder if some kind of technological change has mattered. Are fewer people shoveling and more people using snow-blowers? Alternatively, a societal change could be responsible. Are old people less likely to be living independently where they are responsible for their own shoveling? I would imagine that people are less likely to live near where they grew up and thus that having the kids or grandkids do the shoveling is less likely, but maybe it's offset by more people in assisted living or something?
Maybe the growth of the service economy away from the do-it-yourself economy, with more guys with big snowplow trucks coming around to push the snow off your driveway, like in that 30 year old Simpsons episode where Homer and Barney compete to be the Snow Plow King of Springfield?
I have a female ancestor who died shoveling snow. I never got to meet her.
Climbers head to the Himalayas and the Andes to mountain climb in the summer and it's fairly dangerous. Not sure if an Everest avalanche tourist death in late spring might be counted as a Tibetan heat related death or not.
Death by hypothermia being more common in hotter climes actually makes a good deal of sense to me. Yes deserts are hot, but they also shed heat incredibly quickly once the sun goes down as anyone who's spent a fair bit of time in Africa, the Middle East, or even Utah can attest. Getting caught outside after dark without a blanket or warm clothing is a legitimate and widely recognized danger.
That said I don't see how that would translate to people dying of heat-stroke in Greenland. A rash of malfunctioning saunas maybe?
But isn't sub-Saharan Africa mostly non-desert?
This was what I was thinking. You can actually get it at a surprisingly high temperatures if the conditions are right. This is especially true if you are wet. Back in the army I remember hearing about a couple of Ranger school candidates who got separated from the rest of their class at night and both died of hypothermia before they were found. They were in the Florida everglades at the time, obviously not known for it's cold temperatures. But they were wet, likely were not able to get dry, and died when they had no way to keep their body temperature up.
Just spit balling but it could be that in places that don't have a lot of developed infrastructure it's more likely you can get caught out in the rain or the like and not have an easy way of dealing with it via shelter or heating.
Do you know what the temperature was like? I've heard about people getting hypothermia at 50F.
I don't know what the exact temperature was when those two guys died. However I have seen guys go into the first stages of hypothermia in the mid 50s when it was raining (at which point preventive action was taken). Being wet will drain heat from your body very quickly. Depending on what your clothes are made of it can actually make it worse than if you weren't wearing any clothes at all.
Which is why I'll take scorching desserts and blizzard conditions over 40 degrees and raining. Not only is it miserable it's also sneaky dangerous.
When we are talking about sub-Saharan Africa, what months are winter? Does the flu season actually correspond with the lowest-temperature months in all these places or does the fact that it's flu season in other populous parts of the world change that?
Dunno about SSA specifically but as far as I can remember in Australia and South America the flu season is usually the southern winter (June to September) not the northern one.
Yes. Flu season is generally in the winter, and winter in southern hemisphere is around June-August.
Not particularly happy with any of the studies either, or our ability to draw conclusions from them.
But one thing I found interesting was the global mortality rates with income-based adaptation (like more a/c) mentioned in Bressler. Logically, as people get richer, they can offset some of the heat-related deaths by investing in adaptation, and the higher emission mortality rate decreases from 6.2% to 4.2% when this effect is included (a not insignificant effect).
But one piece that is missing is many proposals for mitigating climate change (e.g. a carbon tax) have economic costs that will compound and lower global economic growth over time. If income-based adaptation to heat can have a significant impact to global mortality projections, how much of a decrease could the foregone income from lower growth rates have bought (across not just heat adaptation but all healthcare-related investments)? Isn’t it possible that the effects on mortality of having $10’s or $100’s of billions less of global GDP over a period of 60 years would swamp any direct change in the mortality rate from temperature changes like the ones forecasted?
This, of course, would say nothing about whether those costs or mortality benefits would be equitably distributed, but it’s a piece of the puzzle that is rarely pointed out in papers that seek to quantify specific costs of letting the temperature rise.
You can make eg a carbon tax less of a drag on the economy, if you make it revenue neutral by lowering eg income taxes or capital gains taxes etc.
Definitely. But unfortunately, most of "benefits" of making it revenue neutral would go to the top end of the income bracket (or corporations) because they pay the vast majority of income and capital gains taxes. And I see that being particularly unattractive in today's political climate (whether rightly or wrongly). And even if it did come to pass, I would expect it wouldn't be long before calls were made to raise taxes back to where they had been to make them pay their fair share.
There's also the concern that a carbon tax, once enacted, even if initially passed in a reasonable form that considers the impact on growth, would be too tempting of a source of future government funds to keep low or revenue neutral.
In theory, an optimal solution might be a smaller carbon tax in developed countries (at a rate less than that required to fully limit or quickly reduce emission growth) with the revenue generated sent to developing countries to support their growth and the future costs of adaption. Essentially attempting to optimize the growth vs. cost tradeoff, while also addressing a more equitable distribution of future costs. But I think that has nearly zero political chance of happening and, in practice, would be subject to problems that all development aid has (like elite capture and misdirection of funds) in addition to being politically unpopular at home.
The set of people who write the cheques to pay for a tax, and the people who bear the economic burden is not necessarily the same.
What makes you think that carbon emissions, and thus carbon taxes, wouldn't increase with income? Rich people buy more goods and services.
Of course, if you want to, you could not fiddle with income taxes at all, and just hand out the proceeds from the carbon tax equally to all voters (or all citizens or so). But as you suggest, that would increase marginal tax rates, and thus be bad for economic growth.
In general, most of the time when you worry about marginal tax rates, you are implicitly worrying about whether rich people pay too much tax.
(Most of the time, because land value taxes are kind of ideal here. No deadweight losses, and still rich people bear the brunt of it.)
I am not sure I follow your ideas about global taxation, and sending money around.
As far as I see it, each country would levy carbon taxes by themselves, and cross border trade taxation would be handled like we handle VAT when crossing borders right now. No need for global coordination.
(Rich countries sending money to poor countries might or might not be a good idea. But that's independent of carbon taxes.)
I'm aware of that. My point was that, if you attempted to make a carbon tax revenue neutral, you would have to lower some other tax (or do some kind of distribution). And since most other tax is paid disproportionately by the wealthy, that would be seen as "a gift to the rich", even if the incidence of the carbon tax ended up being just as progressive as the income or capital gains tax you lowered. Also, status quo bias would mean, I think, that it's unlikely that other taxes would actually be lowered enough to make the carbon tax truly revenue neutral, given that not decreasing the income tax rate by, say, 5% is more politically palatable than increasing it by 5%.
A carbon tax-funded UBI might be a way around that (although I have seen a large constituency for that solution). I've often thought that a UBI funded at least partially by Pigovian taxes (including "sin" taxes on cigarettes and alcohol and taxes on pollutants other than CO2) made a lot of sense. Because it would mean people who contribute less than average to the externality (through their consumption) would be net beneficiaries, while those who contribute more would pay for it. Which is the incentive you want, but without the additional distortion of larger government expenditures.
Sorry if I was unclear about sending the carbon tax revenue overseas. I was saying that the optimum policy overall might be in the middle: to mitigate some and adapt some. In other words, having a lower carbon tax than would be needed to return to early 20th century emission levels but having it be offset by higher growth which makes adaptation easier. But an argument I've heard against that is that the higher growth would happen in the rich countries, whereas the costs of adaptation would be borne disproportionately by poor ones. So I was just trying to suggest something that, theoretically, might tackle both issues at once. But as I said, it's a non-starter anyway before you even consider whether it would work in practice.
Hope that's clearer.
Yes, that makes sense.
Btw, the easiest way to help people who currently live in poor countries is for people in other countries (especially in rich countries) to open up their borders some more.
If you want to offset the carbon tax revenue, you can lower the marginal income tax rates for tax rates for the lower income tax brackets.
That would mean most of the benefit would flow to lower income people.
(Just straight up handing out a UBI can be seen as an extreme variant of this.)
But as said, that would increase effective marginal tax rates on the rich.
"Logically, as people get richer, they can offset some of the heat-related deaths by investing in adaptation."
This is basically the argument Bjorn Lomborg has made - and keeps repeating - in several books & articles & interviews.
Curbing global warming by moving to (presently much more expensive & less reliable) solar&wind power will reduce future GDP growth. This means we will have fewer resources available in the future than we otherwise would have, to mitigate negative effects of climate changes (in this case by building more "temperature-resistant" dwellings). Reducing such negative effects is particularly important in middle- and low income countries, as illustrated by many of the comments above.
Remember that risk = hazard x vulnerability. It is possible to reduce global warming-related risks either through (presently very expensive) policies that (hopefully) reduce the future temperature incease (= the hazard), or by policies that reduce the size/depth of the consequences that a temperature increase implies (= the vulnerability).
Unfortunately, there is a possibility that the net effect of present-day carbon-reducing policies (aimed to reduce the hazard), will end up increasing the total suffering&deaths from climate-related phenomena in the future, since such hazard-reducing policies will mean that we have fewer resources available for vulnerability-reducing policies.
California might possibly be an interesting future test case in this regard.
Except that it is no longer true that moving to Solar and Wind will hurt GDP. That might have been true when we were discussing a carbon tax to make non-renewables more expensive(thus improving renewables competitiveness). Instead we made some fixed investments in Solar and Wind which have now paid off and now renewables are making non-renewables uneconomical.
At this point sticking with non-renewables will stunt economic growth and hurt GDP.
Outside hydroelectricity, renewable currently cost more, because you need to build a back up when they don't work. Every country in Europe that has a huge percentage of renewable has a more polluting electricity because of this backup, and they pay far more for their electricity than Sweden or France, who rely on a low carbon hydro and nuclear mix.
Be careful not to confuse the price of solar when solar works compare to the average cost of solar.
What exactly do you think you are paying for solar when it is delivering 0 power(not working)? Solar and wind have made coal and other non-renewables uncompetitive. Solar energy today is the cheapest energy in history.
https://en.wikipedia.org/wiki/Cost_of_electricity_by_source
Hmm, I'll have to look into those numbers in more detail...
I would expect that the costs would vary wildly from place to place.
I'm especially surprised that there doesn't seem to be an effect yet of the best onshore wind spots having been saturated.
You realize, if a wind location is already utilized you just need to build a taller windmill. There is no such thing as a saturated wind "spot."
The maintenance, the depreciation(need to be rebuild every 25 year), the infrastructure around it, and the other way of getting power(which you must maintain even when they don't give you electricity because there is sun). How do you explain with your sources that Germany (coal/gaz/renewable) pays far more for its electricity than France (nuclear/hydro) ?
Exactly. Unfortunately, with the "with us or against us" mentality that permeates this issue, this kind of analysis can quickly get one labelled a "climate denier" and so is not acknowledged or reconciled with as much as it should be. The same could be said for studies that try to quantify any of the possible benefits of climate change (such as greening, longer growing seasons, few cold deaths).
No matter where you stand on the issue, rationally it's a shame that the discourse seems only to allow for research into things that go on one side of the scale. Because even if the proposed policy interventions are required or the best we can do, a better understanding of both sides of the equation is needed to optimize the implementation of those policies.
Yes. It is quite baffling to see how those who common-sensibly say "how about doing a risk assessment & cost-benefit analysis, just in case" are almost screamed at. I knew Lomborg's writings before he started writing about climate policies and became famous. His was your typical Danish feet-on-ground evaluation researcher, destined to spend out his days in the army of pleasant & anonymous dry-as-dust cost-benefit evaluators. Suddenly he was catapulted to herostratic fame, and/or to a social role almost resembling Doctor Stockmann in an updated version of Henrik Ibsen's 1882 play "an enemy of the people"
https://www.youtube.com/watch?v=9PrCS7ha8jM
...Political tribalism moves in mysterious ways.
There certainly seem to be a lot of non-screaming articles about how Lomborg's "risk assessment and cost-benefit analysis" is wrong...
eldomtom2: A reference or two would be nice....
Here is the latest (July 20) summing-up-the-debate article by Lomborg, it is open access. I find it a quite interesting walkthrough of possible consequences of global warming:
https://www.sciencedirect.com/science/article/pii/S0040162520304157
For the record, I am not at all saying that other conclusions & policy strategies than the ones Lomborg advocate are "not rational". First, rational people may legitimately disagree about which future trajectories/estimates that are most likely.
Second, even if a group of people should agree which trajectory/estimate is the most probable, they can still legitimately hold different preferences as to their degree of risk-tolerance. An extremely risk-averse decision-rule-under-uncertainty, which Scott implicitly referred to in a former post, is "avoid disaster". If you define "disaster" as some uspecified tipping point being reached, where everything spins out of control and the Earth ends up like Venus, this means that you should fight global warming tooth and nail, even if you should regard the probability of such a dramatic spinning-out-of-control as less than 0,000x. Since it is not in itself irrational to be extremely risk-averse.
...That said, I have to add that a problem with the extremely risk-averse "avoid disaster" decision rule is that if you follow such a rule in your daily life, you should never leave your house - or vote in elections, since the probability that one vote will determine the election outcome is less than the probability of being run over on the way to the voting office (also known as the famous "Paradox of Not Voting", but that is a different discussion).
Third, people can legitimately disagree on their time preference, i.e. how far into the future they think it makes sense to compute likely cost and benefits - and rational people may also legitimately disagree on what should be the proper discount rate. Related to this, a problem I have with Lomborg's calculations is that he stops in 2100, only 79 years from now.
Admittedly, everyone reading this blog will be dead buy then, but you can legitimately argue that an ever longer time perspective is warranted.
(Then again, some could also - again, legitimately - argue that even 2100 is too far off.)
To end with my own debate preference: What I would have liked to see among combatants on both sides, is sensitivity analyses - how sensitive are the various scenarios & accompanying risk assessments & cost-benefit calculations to different specifications of the many assumptions one must necessarily make?
This is not how global warming risks & accompanying global warming policies are discussed.
(I don't really blame the journalists for that, though, for who but die-hard policy wonks would read such stuff.)
I was referring to the reaction to Lomborg's work The Skeptical Environmentalist, as I was assuming that who I was responding to was also talking about it.
But as for more recent works, this seems a level-headed critique of False Alarm: https://www.lse.ac.uk/granthaminstitute/news/a-closer-examination-of-the-fantastical-numbers-in-bjorn-lomborgs-new-book/
> Curbing global warming by moving to (presently much more expensive & less reliable) solar&wind power will reduce future GDP growth.
You sure about that higher cost?
https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#/media/File:20201019_Levelized_Cost_of_Energy_(LCOE,_Lazard)_-_renewable_energy.svg
Take that savings and buy into grid storage instead. We have viable options now, and even better ones just a few years out.
This assumes policies should be based solely on how they reduce mortality.
Not at all. It was just in response to a study that focuses only on the effect on mortality rates.
I'm in favor of an approach that includes all costs and benefits in the analysis. So, yes, you need to look at the costs of the policy (e.g. lower economic growth) in addition to the benefits (e.g. a net reduction in mortality rates) vs. inaction (or an alternate policy).
It just so happens that effects on economic growth are particularly important because of compounding, with the added factor that growth is "fungible" in the sense that being richer can be used to offset many different kinds of harms or provide many different kinds of benefits.
That said, it's not the end of the story because certain effects may be incommensurable (e.g. loss of biodiversity, more government centralization, or loss of cultural heritage). And as I sad, it's not just the net total that matters, since distributional impacts are important (though they may have a Coasean solution).
I suspect one reason why cold cities over-adapt is that some of the important ways cold is dealt with tend to be fairly binary. That is, you aren't really optimizing houses for a particular temperature, you're optimizing them for heat retention (within some bounds, of course, but it's not a very granular decision). You either have heating infrastructure or you don't (and if you do you either have laws and norms about making sure people get heating even if they can't really afford it or you don't). Sure there's more gradation at the personal level with things like various jackets and coats being appropriate for various temperatures, but at the level of construction and governance there are big, binary choices and as they get made they push you into being over-adapted.
Can someone ELI5 those graphs of mortality in cities? I don’t understand how the histogram of deaths relates to the curve.
Three comments. The first is a point already implicit in your discussion, but one that I think you missed earlier and many people still do. Heat mortality isn't just, probably isn't mainly, people going out in a heat wave and dropping dead. Cold mortality isn't just people freezing to death. Those are dramatic examples, but probably more important are the people who are made a little worse off by heat or by cold, a few of whom die sooner than they otherwise would.
The second is something that I noticed looking at the latest IPCC report and that they, I think, never mention. The effect on heat or cold-associated mortality depends on how much warmer climate change makes winters, how much hotter summers. The report gives projections for the change in how hot the hottest day of the year will be in various places with various amounts of global warming. It has a chart showing how cold the coldest day of the year will be in various places with various degrees of warming.
I looked at how much hotter the hottest day got in hot places and how much colder the colder day got in cold places. The answer was that the coldest day in cold places got two to three degrees warmer for every degree of global warming, the hottest day in hot places got about one degree warmer for every degree of global warming. Warming makes winters milder and summers hotter but, at least for the places I looked at, the former effect was two or three times stronger than the latter. The report never made that comparison, provided the necessary information in different places and contexts for warming and cooling.
Similarly, the report routinely said that climate change had both effects but paid attention almost entirely to the effect of hotter summers. That fits my general view of the report, that the authors honestly report their results but are looking for reasons why climate change makes things worse, not reason why it makes things better. If you don't look for something you are quite likely not to find it.
I was thinking in terms of temperature extremes and had not yet read your post, so it didn't occur to me to look at the effect of warming on cold extremes in hot countries or on hot extremes in cold. Looking at those, the pattern is less extreme, but the qualitative difference remains — in most but not all places, climate change raises minimum temperatures more than maximum. I find in the Summary for Policy Makers:
"Some mid-latitude and semi-arid regions, and the South American Monsoon region, are projected to see the highest increase in the temperature of the hottest days, at about 1.5 to 2 times the rate of global warming (high confidence). The Arctic is projected to experience the highest increase in the temperature of the coldest days, at about 3 times the rate of global warming (high confidence).
My third comment has to do with the various attempts to actually measure the mortality effects. None of them should be trusted, at least until you go over them carefully. If an honest and intelligent person solves a simple problem he is quite likely to get the right answer. The more complicated the problem is, the more his answer will reflect either what he expects to find or what he wants to find. For an example outside of climate issues, consider the history of measurements of the charge of the electron.
Thanks, I think those are really good points! Especially the second looks pretty important.
"That fits my general view of the report, that the authors honestly report their results but are looking for reasons why climate change makes things worse, not reason why it makes things better."
I've read large chunks of the IPCC reports and well over 1000 papers on climate and this is a clear trend.
A few examples, I could give 50:
1. The exec summary of a section of an IPCC report says "We have low confidence in a global increase in droughts", but the report says (reflecting the underlying papers), some climate scientists find an increase and some find a decrease. If you skimmed through the exec summary only you might conclude that there is an increase but it's not as certain as other climate related things.
- The exec summary should say "we don't know whether droughts have increased or decreased globally".
2. A paper on sea level rise affecting megacities concludes "if we stop global warming we can delay the flooding of 1/2 of Bangkok and 1/2 of Shanghai (can't remember the exact percentages) from 2100 until 2115".
But the paper itself clearly explains that these cities are sinking at 10x the rate of sea level rise due to overbuilding and groundwater depletion.
- The conclusion, more reliably, should say "we can delay the flooding until well into 2200 if we stop groundwater depletion and overbuilding".
3. In the impacts section of an IPCC report it begins, and continues, with a litany of all the woes that will fall on sub-Saharan Africa due to anthropogenic global warming. If you read until the end of the section - of course, hardly anyone does that - you find the apologetic footnote - "Of course, this depends on crop prices being higher in 50 years time which is highly uncertain".
If it was me, I would start with that, but then no one would read on.
- The crop prices depend on economists being able to reliably predict supply and demand in 50 years time, when in advanced countries their track record of predicting GDP and unemployment in 12 months time is pretty bad. The supply depends on availability of crops, which in part comes from taking rainfall projections and feeding that into crop models and pumping that into the economic model. There are 20 climate modeling centers in the world and their models project everything from halving to doubling of rainfall in many places in the world, including sub-Saharan Africa. But, to solve the problem, we just "take the average of all the models". The crop models are not calibrated via experiment to the projected CO2 in the atmosphere, the rainfall, the temperature and a few other variables, they are just extrapolations. And no account is taken of the fact that if in fact rainfall does vary from current climate new crop variants will no doubt be introduced.
My conclusion is that most aspects of future climate, and the consequences, are unknown, apart from higher temperatures and higher sea level. Probably slightly higher rainfall globally.
Thanks for these detailed comments on the IPCC report.
My general experience from reading such expert reports (and I have read many), is that you should read the chapters in the actual report, where the scientists are allowed to write their stuff, and drop the "policy relevance" chapter at the beginning or end of the report, which is usually written by the people in the organization - and they often have a policy agenda to push.
The scientists by contrast are usually contracted in from outside universities to write various chapters, and they have their reputations in the scientific community to think of . So they usually - or at least more often - avoid "stretching the hide further than the skin allows", as we say up here in Scandinavia.
In my experience it is not the details of the IPCC reports that are objectionable, it is the media telling us "what the science says". There are certainly a few activist scientists exaggerating the possible downsides of climate change, but environmental journalism is comprised almost entirely of activists. I have been consistently appalled at how a few areas I have looked into get reported in the media (sea level, hurricanes to name a couple).
This state of affairs is not entirely surprising as the reporters at ESPN are no doubt all sports activists. However something has gone horribly wrong in climate change reporting, it is a political monoculture without peer. I literally cannot read it any more.
The media are much worse than the IPCC.
As I read it, the IPCC report is an honest account by people who are looking much more for bad things about climate change than for good things, so more likely to find them.
The Summary for Policy Makers is that report filtered by people trying to scare their audience and more willing to misrepresent things than the authors of the report.
That plus everything else filtered through the media is a scare story designed to get readers and persuade them of the horrors of climate change, written by people most of whom don't understand the science or much care about it.
I was reading an article about why cropland real estate prices in northwest Iowa have grown so high in this century, and one reason given was that climate change had improved the climate for growing grains in the region. That struck me because you so seldom see any mention of positive sides of climate change in the press, even though in daily life everybody hears plenty of complaints about the current weather.
There is a general "greening of the planet" tendency at the moment. However, it is hard to separate the greening effect due to increased CO2 in the atmosphere, and greening effects due to other causes, e.g. ongoing urbanization or deliberate tree planting. In Europe, forests are growing fast, but that is mainly because people leave the countryside and forests reclaim so-called "cultural landscapes".
There is also a discussion if the ongoing greening of the planet is good news or bad news. Trust humans to see a possible downside of everything. Link:
https://www.bu.edu/articles/2019/humans-are-officially-greening-the-earth-is-that-a-good-thing/
The "greening" in the article is increased agricultural output, which I wouldn't expect to reduce CO2 much. Crops get cycled back into the atmosphere when people "burn" those calories.
There is a one time consumption of CO2 when a tree grows, but a mature plant isn't a net consumer of CO2. I'm interested in greening not as a way of reducing CO2, although I suppose it does a little of that, but as a way in which CO2 has positive externalities, most notably increasing crop yield and decreasing plant need for water.
It seems possible to me that increased CO2 is partly responsible for increased crop yields over the last few decades.
Undoubtedly, for instance greenhouses will run at 1000+ ppm of CO2 which I suspect we won't reach
Plenty of evidence that CC has been neutral to good for US agriculture.
Good weather for corn: https://pnas.org/content/115/47/11935
CC explains some of recent increase in corn/soy: https://sciencedirect.com/science/article/pii/S0095069620300292
Potentially large CO2 fertilization effects: http://nber.org/papers/w29320)
Globally though, picture is a lot bleaker.
Do you mean that yields elsewhere have gone down or that other places have had less positive, more negative effects?
So far as CO2 fertilization is concerned it is less for C4 plants, and the most important C4 crop is maize, which the U.S. is the largest producer of.
Not as knowledgable on global data as US data, but my point was that (1) US ag may (likely, but not certain) have benefitted slightly from prior warming (mostly through more favorable weather for maize in the Upper Midwest) and (2) that CC is still a BIG NEGATIVE globally, as much of the world's fertile soil lies in climates that are much warming that the Midwest (and thus do not benefit from additional warming).
Agree that, other than wheat, CO2 effects are likely to be very small.
Co2 effects should be significant for any C3 crop, which is not just wheat but everything major except maize ("corn") and sugar cane. Doubling CO2, roughly what the IPCC expects by the end of the century, raises the yield of C3 plants by about 30%.
Do you have any evidence that climate change is a big negative globally? Wheat yields are graphed at https://ourworldindata.org/crop-yields. India's yield (tonnes per hectare) has been going pretty steadily up since 1961. Their graph for world yields of various crops shows a generally rising trend, with rice, for example, more than doubling its yield since 1961.
Here's a meta-analysis I think is good. In hot climates, warmer years typically are associated with lower yields. https://www.nature.com/articles/s41467-017-01792-x
Yeah, it's definitely true that technological progress over the past half century has overwhelmed any decrease in production attributable to a less suitable climate. But this doesn't mean that climatic conditions haven't worsened in some areas. Only that they've been more than offset by gains from improved tech and/or management practices.
Excellent post, thanks.
Kampala, Uganda not only never really gets cold, it also has practically no seasonal variation in temperature. If someone has actually calculated temperature-related excess deaths for it, that must be from random weather changes, rather than seasonal changes.
Given that Kampala or similar places likely have no heating at all, and little insulation, a cool temperature outside corresponds to cool temperature inside. If the relation between colder temperatures and heart attacks exists even at near-room-temperatures, it's plausible that there are more heart attacks in Kampala at relatively cooler temperatures.
Scott, how long does it take you to put together a post like this? Just finding and processing these disparate sources on this out-of-left-field topic is something. But you actually synthesize them into a meta-study, which you wrap head to toe in engaging prose. (Or are there some behind-the-scenes researchers or editors contributing to this production?)
Feature request: Provide subscribers an estimated Hours To Produce figure on your posts?
I think the range will be pretty large. I'm curious myself about the figure for his "much more than you wanted to know" posts, which are far longer than this: https://slatestarcodex.com/tag/much-more-than-you-wanted-to-know/
Not that relevant to us until Scott releases his formula for the forty hour day.
This one probably took between 5-10 hours, although it's hard to tell because I'm bad at working straight through as opposed to switching back and forth between tabs.
I don't know if this is supported by evidence at all, but I think it's one possible solution to the paradox: suppose that temperature-related deaths are, for whatever reason, extremely non-linear with temperature. For example, suppose that you get 90% of heat-related deaths between 95F and 100F and 90% of cold-related deaths between 60F and 50F. Then in the hottest countries, heat-related deaths might be spread so evenly through the year that you couldn't identify a relationship between hotter days and more deaths. Similarly for the coldest countries you couldn't identify the cold-related deaths.
But even if something like this was going on, I think it could only explain the very hottest and coldest countries - if the trend holds up when just looking at the countries in the middle, then I don't think this would explain anything. From eyeballing the graph it seems like the trend does hold for the middle countries.
> Everyone says that global warming will worsen mortality from heat. I’m a bit confused by this also
There's an asymmetry here that might be worth noting: when it's cold, you can usually put more clothes on to warm up. There is only so much you can take off when it's hot.
(I've always found that frustrating, because I'm increasingly incapacitated by temperatures beyond 75F.)
A possible explanation for the data in Bangkok and other tropical parts of the world - the "cold" season is not just winter, it is also the rainy season when the disease burden and mortality go up every year due to a whole host of diseases of which flu is just one of them. Examples of other illnesses include dengue fever and leptospirosis.
This is certainly the case in my home state in India, Kerala. Mortality goes up in the rainy season which is not cold by any measure. But the absence of sunlight, presence of stagnant water etc probably does as much damage as colder weather does elsewhere.
It is difficult to find many papers on this subject but a a review of "fevers" in Asia is https://www.sciencedirect.com/science/article/pii/S1198743X18302544. Random newspaper articles on the monsoon season and disease in Kerala - https://indianexpress.com/article/explained/fever-panic-in-kerala-numbers-and-the-reasons-4715870/ https://theprint.in/india/dengue-h1n1-leptospirosis-the-monsoon-challenges-kerala-faces-besides-coronavirus/433127/
That would tally well with what happens in the Andes: there, summer can be (warmer but) rainy, cloudy and a bit miserable.
Mosquito season would seem more of a threat to health in the tropics than warm or cold season.
I think these sorts of studies miss some huge confounding factors related to some of the details that excess death numbers just cannot get at. In Michigan, where I live, we get a few pretty severe hot days in the summer and a few pretty severe cold days in the winter. When it’s severely hot out, we have old people dying in un-air-conditioned homes, since many here still don’t have central air and many old people cheap out about putting in window units until it’s truly hot out, not to mention farmers and construction workers who have to work in the heat. On the other hand, we get fairly few direct freezing to deaths in the winter because everyone has heat and most people avoid activity when it’s that cold. We get far more winter deaths from icy roads or heavy snow or the heart attacks from shoveling snow than from the temperature per se. This is compounded by the fact that below about 0*F we tend not to get much snow, so much of the direct causes death decrease below a certain temperature.
I think this analogizes well to the pandemic, actually. Despite the lockdown orders here, and despite the number of people working from home, traffic deaths went up in 2020 vs 2019. Way more people took advantage of empty freeways and the state troopers explicitly saying that they weren’t going to interact with people early in the pandemic just to write tickets to do dumbass car racing at 120 mph on the freeway and wrapped their shiny Shelby 350s around a bridge abutment. Similarly, some of the stay at home prevented flu deaths, but increased, say, cancer deaths due to delayed diagnosis. These things are often deeply complex systems with complex causation and I see no reason why temperature related deaths would be different.
Does your metabolic rate vary over the year? Could that be relevant?
Here's the best paper I've seen on why flu is worse in the winter:
Seasonality of Respiratory Viral Infections, Miyu Moriyama, Walter J. Hugentobler, and Akiko Iwasaki, Annual Review of Virology 2020
A thought and an anecdote:
The thought is that I am surprised you didn't mention increased traffic fatalities as one of the possible contributors to excess cold deaths. Obviously less relevant in places that don't get snow/ice in the winter, but where I am from traffic accidents do go up considerably once the roads are covered with winter yuck.
The anecdote:
It probably doesn't shed any direct light on the human data, but when I was growing up my family saw a very clear pattern in seasonal mortality of our flock of pet chickens. We typically had around 20-25 at any given time, and most only live to 9-11 years (actually somewhat bimodal with a peak at 5-6 and the other around 10) so we got a fair number of data points, and deaths of 'old age' clustered around early winter and mid spring. The early winter makes sense, they had an insulated chicken coop with an electric water heater and an electric heater in the coop, but they were still essentially living outdoors and the cold is an extra source of stress on the oldest/frailest. But the odd thing was the spring peak, which was actually the higher of the two. it was before the summer heat came in, but still well into spring and we could never figure out what the stressor was when the weather was that mild except that it must have something to do with the change in temperature moreso than the absolute temperature, especially since the winter peak was well before the coldest part of the year.
Interesting about the traffic accidents. I've long had in mind the statistic that where I live (Northern Europe) there are four times as many motorcycle accidents in the summer as during the winter. Although it's initially counter intuitive, the important hidden information is that there are six or seven more motorcycle-miles ridden in the summer, and in the winter it's only the hardcore pros who are still out on two wheels.
We have a flock of 'pet' chickens too, but I'm afraid the data I have on their seasonal mortality is overwhelmed by the confounders called foxes and pine martens. And the fact that if the chickens survive long enough for us to notice their egg-laying has diminished, it's usually time for us to put them in the oven. We don't have many that make it to four years old, but though their lives are relatively short, I like to think they're full of chicken-joy..
there's also light levels as a confounder. Once the clocks go back here, everybody will be commuting home in the dark.
In the U.S. traffic fatalities were up relative to miles driven in March-May 2020, but the real explosion in road deaths were up 36% in the last 7 months of the Racial Recockning of 2020 among blacks but only 9 % among nonblacks. It's almost as if the media-declared "racial reckoning" convinced blacks that the white man's law didn't apply to them. Thus black road fatalities in June 2020, the first full month of the Racial Reckoning, were 55% worse than in June 2019.
It's almost as if when the Establishment declares that rule of law no longer applies to blacks, who are now morally entitled to resist arrests, then blacks tend to shoot enough other more and kill each other more in car crashes.
Funny, how that works.
Don't extreme temperatures cause mortality in a lot more ways than listed here? They just sort of generally take a toll and make you more likely to die if you're sick, heat makes people more violent, cold makes people less social, etc. In places that aren't super food-secure they cause famines.
Just so I've got a handle to work with the equal and opposite ideas of more cold deaths in hot places and hot deaths in cold places, I'm going to refer to them collectively as environmentally oppositional deaths (EODs). So my first thought was that the EODs might be caused by excessive environmental controls: setting the A/C too low in hot places and cranking the heater too high in cold places.
There's a meme in some places that the weather forecast is always wrong (statistics to the contrary notwithstanding). In places where this idea is pretty widespread, would people develop a habit of compensating for how wrong the forecast is? Would this lead to unexpected extremes, ones bad enough to up the number of EODs?
Anecdotally, recently a small cold front went through, so we turned the heater on for the first time this season to brace for it and to get the cobwebs out for the months ahead. Unfortunately we didn't know how small the front actually was, because in the middle of the night we were woken up by how hot it was. I checked the thermostat, and while the heater was set to only 70, the temp gauge said it was 77 in the house! That's 7 degrees of difference, and compared to the usual climate here, that was a rather mild night. If something like this happened in a place with more extreme temperatures, I can't imagine how bad the temperature differential might be from such a mistake, and how many EODs that might lead to.
Maybe I'm missing something obvious, but I thought the flu is seasonal because people spend more time inside in crammed spaces in winter.
The problem with this explanation is that it's not specific to the flu; if that's what it was, all contagious diseases would be winter-seasonal, but in fact, different diseases have different seasonalities, and the reason isn't well-understood. See https://www.sciencemag.org/news/2020/03/why-do-dozens-diseases-wax-and-wane-seasons-and-will-covid-19 for an overview.
This does not fit the pattern in countries like Saudi-Arabia, where people (have to) stay inside in summer due to the heat. The flu wave is still in winter.
Still, it's one of the best explanations that we have, even if it does not match all countries.
Another one is that UV radiation is stronger in summer, and is really bad for airborne viruses. But I also think that it doesn't really fit for countries like Saudi-Arabia, where UV radiation inside of buildings is probably not an important factor.
I would like to see these numbers controlled for schools in session. I find it highly likely that many seasonal diseases are seasonal because schools are usually packed full of children who pass illnesses to one another, are often asymptomatic or lightly symptomatic, and then go home to their families who are more susceptible.
This seems very plausible - I caught Covid from my daughter, exactly when the lockdown ended here (Czechia) and she started going to school again. Also, the lack of flu last year may be explained by the widespread use of respirators + lots of online schooling in most countries.
Except polio used to have an august season.
But then seasonal diseases wouldn't be seasonal, they would be...three-quarters-of-the-year-al, and we wouldn't expect it to be any worse in December/January/February than it is September-November or March-May.
This feels like the kind of post where it might be worth just calling up someone in the field and asking them questions for 45 minutes. I know that has never traditionally been the format of this blog but it would probably be a shortcut to a lot of interesting stuff that hasn't been synthesised in any published papers yet. In my experience, not every scientist you email will want to talk to you, but a lot of them will.
Agreed.
One point which has not been stressed here at all is the role of humidity especially for feeling cold. The effort to keep up a certain temperature increases with humidity due to higher heat capacity and conductivity of wet air (20C in water is quite different than 20C in air). This effect should be expected to be higher in warmer regions where humidity is higher and the number of layers of clothes is less.
We have examined relationships between mortality and cold and hot weather effects in Hong Kong. Basically the cold weather effect on mortality is pronounced and is independent of influenza rates. Also almost all causes of death are affect (except for cancer and accidents) not just cardiovascular deaths:
https://ehjournal.biomedcentral.com/articles/10.1186/1476-069X-12-59
Hong Kong is a good place to test this as the weather during winters varies considerably. During some winters temperature rarely go below 15C while others have been characterized by long cold spells (by our standard a cold spell has temperatures < 15C). During those winters with colder temperatures we see a lot more excess mortality. So not seasonal (at least not here).
Seasons in the Andes are not like seasons elsewhere. Winter is sunny and dry, with blue skies; summers are damp, and it's cloudy, and not that hot. (There are also mudslides during the summer, but much of their damage is to lowland regions lying further downstream.) Yes, in winter, it's chilly in the early morning, or even mid-morning if you are in the shadow (and it's temperatures in the shadow that are usually recorded, no?), but there's plenty of radiant heat from the sun. Of course too much UV can also cause problems, but generally not immediately - you could get skin cancer or sight problems later on. I'd certainly say winter *feels* healthier (to me, and to anybody else who is somewhat affected by asthma/allergies), at least in the regions that Peruvians think of as having "moderate altitude" (< 3750m or so).
While we are at it: global warming affects much more than just ocean levels. Andean glaciers are melting rapidly. Momentarily, the effect is not entirely bad (more water! good harvest! ah, ok, mudslides, but those are partly further down), but in the medium to long run, it's bound to be pretty terrible - without glaciers and less rainfall, the entire region could become basically uninhabitable (or really uninhabitable, according to some projections).
I'd expect regions to adapt according to comfort, which might be more than is needed to not die. So from a perspective that's only about death rates, it looks like over-adaptation.
Accidents are the number 3 cause of death (in the US anyway), and it seems plausible that you’re more likely to have an accident when extreme conditions force you to do things differently than normal. Maybe?
Also, FWIW, if their model uses 0.5 degree latitude by 0.5 degree longitude squares, that means the equatorial squares are much larger than the polar “squares”, though I’m not sure that helps explain anything…
These both seem like points worth considering (and commenting on this post will make people more likely to look at it.)
I don't have time to check this carefully right now, but keep in mind that car crashes occur more frequently during cold months. Northern countries have methods of dealing with slippery roads such as spreading sand or mandating use of snow tires on vehicles. I assume that warm countries do none of these things and instead get surprised when the occasional cold month hits them.
My personal experience is that the change in temperature or any environment is a challenge to the body. 16°C in October feels cold, the same temperature in April makes me thinking about wearing nothing but a t-shirt (and if you see people wearing t-shirt in April - that are tourist from scandinavia visiting Germany).
How does this effect sub-sahara africa? People are used to constant temperatures during their whole live, and they are not trained to handle changes. I know a man in Bujumbura, Burundi, who went to hospital in Nairobi, Kenia. He felt uncomfortable because it was too cold (and we are talking about 10°F colder temeratures).
So the environmental changes could be more challenging to people in areas with less seasonal differences.
Doesn't help with iceland though.
My first thought was variation in day length and natural immunity. But then I would've expected a clear trend with latitude.
Still feel like something like this must hold. Would love to see an investigation of the seasonal health of the immune system.
Love to see more things like the following for instance: https://pubmed.ncbi.nlm.nih.gov/8987173/
Some thoughts that I haven’t seen mentioned:
1) You don’t buy the idea of 12C being a dangerous temperature, but have you ever spent a significant period at that temperature in an uninsulated building/outside? It’s freezing!
2) That said, Kampala’s annual temperature curve is basically flat, with a daily mean of 22-23 C all year. The way the main paper fits functions on top of functions, it seems inevitable that trying to draw a signal out of a 1C range will result in nonsense.
3) Nepal/Tibet could be related to the the monsoon, which coincides with high temperatures.
4) Does this post on the harms of cold have anything to do with your time in England?
Re: #1 - yes! I have spent July nights in Malawi, where daytime temps are around 25C; but during the night, it can easily fall as low as 5C. If you're sleeping on a floor, with no mattress, and little by way of blanket/covering, and your diet is extremely poor ... well, it's no fun. Not sure it would necessarily be lethal, but still, for some it could be. (And altitude is surely a compounding factor in sub-Saharan Africa.)
Re: #4 :))
I wonder whether the variability of temperature could play a role. That is a sudden heat wave or cold snap is worse for mortality than if it is always pretty cold or pretty warm. The nordic countries that have low winter excess mortality also have pretty stable climates. Iceland which had no winter excess death has a really low temperature variability (at least in the populated parts). Reykjavik has a daily mean of 0.7C in January and 11.6 in July and record cold of -20C. Nome in Alaska is at the same latitude and has a daily mean in January of -15C and record low of -54C.
A stylized model:
- R-nought for the flu gets above 1.0 in the temperate northern part of the world in, say, November-March and in the temperate southern part of the world (e.g., Buenos Aires, Melbourne) in May-September.
- People from the temperate world travel to the equatorial world more or less year round.
- Temperate people are more likely to bring flu with them in their homeland's winter and infect equatorial people they are visiting.
- There are vastly more people living in the temperate north than the temperate south.
Prediction: More equatorial people get flu in the Northern winter than in the Southern winter.
Is that true?
>very cold places like Stockholm or Siberia
Stockholm is actually not very cold. The average minimum for January is -3, same as New York, as compared to -21 in Novosibirsk. Still, it's cold enough that I'm surprised not to see any mention of the lives lost to slipping and falling on ice/snow (I think about half a percent of deaths), or the QALYs lost to injuries from slipping and also from the fear of slipping and the isolation brought by such fear (among the elderly).
Best scientific treatment I have seen so far on variations in temperature-deaths, and a nice open-ended discussion of possible implications of global warming.
Scott asks the question: Is it reasonable to assume people in cold climates over-adapt to the cold, relative to people in the South? (quote: "Why would cold places adapt so hard that they did better than warm places?")
I think a theory can be formulated. At least I have got one, based on living in the North of Europe and sometimes travelling to the South of Europe to escape winter – only to find myself almost freezing to death in some rented house in the South. (Ok, n=1, but wait for the theory)
Here is the theory: People in the North know that when winter comes and it gets cold, it stays cold for a long time. You cannot wait it out. So you have to put in the money to get central heating and those triple-glassed windows.
While people in the South know that when it gets cold, it usually does not stay cold for very long. If you brace yourself, the cold spell is usually over in three weeks max. You can brace yourself to live through three weeks of cold, but not four months. So you do not adapt at all.
Plus, to some extent people in the South must do the opposite: They adapt their houses to the often very warm summers. That is why I have never frozen more than in the South. Old stone-built country houses in particular (where old people often live), are built to keep the heat out in summer. Which makes the houses ice boxes in winter.
…for US people, a similar logic is captured by Mark Twain’s dry observation: “The coldest winter I ever lived was a summer in San Francisco.”
Finally getting to the testable hypothesis: If I am right that people in the South sit out the cold while people in the North adapt to the cold, we should get excess cold deaths in the South, but only in years with unusually long Southern winters; i.e. when the presumption that “the cold will pass” is not borne out. Scott’s information that cold deaths usually take place 14+ days after the cold spell starts, fits with this assumption.
To test this hypothesis we would need data not only on winter temperatures in different countries and across time, but also variations in how long the winters last. Cold deaths in the South should peak in years where winters surprise everybody by being long.
Finally, a bit of travel advice to ACT readers: Be careful if you live in the North and are tempted to rent one of those picturesque and suspiciously cheap old rural stone cottages in the South to escape your own winter! Speaking from bitter experience….
In the US we have a similar phenomenon with the snow. In North Carolina where I live we get 0-3 days of snow a year and after a snow it is melted and gone within 2-3 days.
Consequently no one either individually or publicly invest in snow removal equipment. We don't salt most of the roads, we don't have lots of snow removal trucks folks don't have snow shovels.
When it snows the city just has a couple day holiday where no one leaves their home and schools are closed. But in Michigan where my wife is from they know it will be an all winter affair so their schools shut down less frequently for snow than ours do.
Confounding this is the fact that Scandinavian countries are not only prepared for cold weather, they do so in rather safe ways. Electrical or natural gas heating, or when wood is burned it is in airtight stoves with well-maintained flues. Here in Nova Scotia house fires and flue fires are common winter occurrences, but we can't afford to do things as well as the Scandinavians. But consider the case of sub-Saharan Africa: most cooking and heating is done over indoor open wood fires in rural areas. Even in cities the electricity supply is unreliable. Open fires mean increased COPD from breathing smoke, and that in turn means respiratory infections are likely to be more dangerous or even lethal. My wife started an orphanage for AIDS affected or AIDS orphaned kids in Kenya, and goes there yearly. She notices how they feel the cold - even when it seems hot to her they will put on coats as 20ºC seems bloody cold to them. So more wood gets burned. More risk of fires, and more respiratory infections from huddling indoors, and those infections will be more deadly in lungs that have been inhaling woodsmoke. Add to that the immunosuppression and general weakness from endemic TB, malaria and AIDS, and you can see why deaths skyrocket in the cold season. One thing we have done is to encourage the use of rocket stoves, which burn less wood (in short supply) and produce far less smoke. There is even a charity dedicated to encouraging their use - see https://www.aidafrica.net/rocket_stoves/
Would you not say that perhaps this indicates that economic growth/higher GDP per capita, allowing Africans to afford rocket stoves (rather than to get them through charity), might be a good idea...
...and perhaps an even better idea would be to get a big coal/oil/gas burning plant that provides stable&cheap year-round electricity to them and their neighbours & nearby towns, so they would not have to burn wood at all.
That may increase longer-term problems, but as you illustrate it would reduce a lot of rather immediate present-day health risks & problems in sub-Saharan Africa.
Just a possibility.
One would have to do a lot of risk assessments & cost-benefit calculations to be reasonably certain a shift in sub-Saharan Africa from wood (or nothing at all) to coal/oil/gas would reduce more problems than the risk of creating problems in the future.
It seems like what you're getting at is that cold places don't just "over-adapt", they adapt in fundamentally different ways. They adapt in rich-people ways, and rich-people adaptations
(that is, adaptations which take advantage of large amounts of wealth) reduce mortality more than poor-people adaptations.
I'm taking the liberty of posting before reading all the comments. If lack of sunlight is a factor in winter deaths, then there should be a weaker winter death effect closer to the equator, even allowing for warmer temperatures.
If excess mortality is caused by temperatures outside the usual range, then moving the range up isn't going to lead to fewer deaths from cold.
For reasons I'm not going into, I live in Philadelphia without air conditioning. This gives me a different understanding of the effects of challenging weather than a lot of other people seem to have.
The high and low temperatures only give a modest amount of information. For *how* *long* was the temperature at or near the high? What were the lows like-- how much of a chance does the house have to cool off at night?
The worst summer weather I experienced was in Philadelphia in 1995. Two weeks of high of 110F and low of 85F, with high humidity. The air felt like it was so heavy it was hard to breathe.
Incidentally, the past three summers here have been relatively tolerable. Previous, the humidity was always pretty high, and I thought that it was inevitable because I'm living between two rivers. That theory is wrong-- the past summers have been at least as hot as the usual (highest temperatures in the 90Fs), but with moderate humidity. I have no idea what's going on.
Brilliant critical thinking.
From experience living in a multicultural family, I believe the over-adaptation to cold is true.
The (simplistic) rational is as follows:
- If you do not wear the appropriate clothing in mild European climate in winter, you might catch a cold. Big deal. People end up wearing unappropriate clothing out of laziness, wanting to look cool/strong (teenagers), and eventually habit.
- If you do not wear the appropriate clothing in Russian winter, you... die. Hence people are much more careful, and the intensity of this effect is non linear.
Slightly counter-intuitive, probably controversial, but all my personal data points support the hypothesis so far.
"You can see further debate between these groups here and here" - Both those links are the same.
I haven't read the papers, but does all of this relate to natural deaths only? Because I would imagine there to be a pretty strong link between suicide, car accidents, falling etc. with the cold (and thus dark) season. Sure, these don't make up the lion's share of deaths, but they surely play a role.
It's really hard to hypothesize about causes without more info, like:
- Separate deaths from transmissible diseases
- Separate deaths from exposure itself (i.e. "freezing to death")
- Attempt to account for "when people spend more time indoors" - this probably varies a lot by region, as some regions consider it "too cold" at different times than other regions. It's not settled fact that flu spikes in winter for ventilation-related reasons, but it's at least part of the equation. Related interesting question... when it's way too hot and everyone stays inside, does that lead to more disease transmission?
Thanks. I realize people are quite confused about this; someone even asks if hot places have winter. But I want to remark at least three main issues with this whole analysis that make me very suspicious about cross-country comparisons regarding deaths, temperatures and seasons:
1) CONFOUNDERS: distinguishing the “temperature factor” and “winter factor” is harder than we think, especially if what you want to measure is the impact of climate on health. It’s not just that there are too many confounders, it’s hard to define what is a confounder and what is causally relevant. For instance, winter is the dry season in Brazil: prices and allergies (because of dust) spike; global warming will likely make this worse. On the other hand, in higher latitudes, you have way less sunlight and significant behavioral changes; global warming may or may not help with that.
2) ADAPTATION: I wonder if physiological adaptation is underestimated. Acclimatization takes a while to be optimal – think about adaptation to changes in altitude; so, gradual transitions between temperatures should be optimal. But in tropical climates, you don’t have that: living in Sao Paulo, you can have 30ºC on a hot dry winter day, followed by a cold or hypothermia with 15ºC on the following rainy evening.
3) VARIANCE and MEASUREMENT: notice that some of the linked papers (those I checked, AT LEAST) used data on the average temperatures (usually the mean between the max-min on the same day). Not only this neglects wet-bulb temperature and windchill factor, it also equates a wet day with min of 15ºC and max of 35ºC (I hate those days) with a pleasant dry day ranging around 25ºC.
I wonder how the results would look when compared with seasonal temperature variability, as opposed to how hot or cold it gets on an absolute scale? Humans seem to benefit from a certain amount of variance, so maybe people who live in places where the annual temperature is between -10F and 60F are better adapted to deal with general physical stressors than people who live in places where the annual temperature is between 70F and 90F.
"I can’t really find anyone taking this seriously and saying that, as colder cities get warmer, their heat-related mortality will decrease."
Shouldn't that be "as warmer cities get warmer, their heat-related mortality will decrease"?
1. Let's say someone had a heart attack/blood clot because of a cold day. You'd expect to see increased mortality about a week or so later, because, while some people would just drop dead, others would go to the hospital and die there. A group looked a weather variables and incidence of DVT (blood clots) and found that around 9-10 days after a rainy day, or a windy day, or a day with low atmospheric pressure (more on that below), there was an increase in blood clots about a week later (source: https://pubmed.ncbi.nlm.nih.gov/19806252/#affiliation-1). It seems more plausible that these effects are mediated by inactivity than the effects of weather on our physiology.
2. Hawaii has VERY little variability in seasonal temperature (coldest month with a high of 80F, hottest with a high of 88F), but has about the same seasonality to respiratory infection and cardiovascular disease as other places with more variable temperatures (source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC28593/pdf/1946.pdf). Please click through and look at how smooth the temperature curve is while the respiratory infection and cardiovascular disease curves whip up and down every year. It just does not seem biologically plausible that temperature effects on physiology could account for such a significant amount of variation. Another way to say this; I don't think increased blood viscosity or peripheral vasoconstriction due to *slightly* colder weather could be causing increased cardiovascular mortality in Hawaii.
3. Inactivity is high associated with all cause mortality (https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2783711) though it's tough to determine causality since maybe people who are sick for other reasons move around less rather than moving being protective (though it does seem that a preponderance of evidence suggest that, all things being equal, not moving around much is bad for you-if anyone thinks there's good evidence to the contrary please let me know).
4. Re: association between low barometric pressure and blood clots I brought up in (1). I think even a short period of inactivity (I'm talking a few hours) likely significantly (but slightly) increases your risk of death in the short term. Case in point, physicians are trained to ask if you've recently taken a long flight when you come in with a blood clot. The reason is that the way blood returns from the legs back to the heart to get recirculated is by being squeezed by the leg muscles during normal activity. When you sit in a cramped airplane for a transatlantic flight, you might sit more or less perfectly still for >6 hours. Blood that's not moving is MUCH more likely to clot, and so you can get a blood clot.
The authors of the weather vs. clots study noted the strongest association between low atmospheric pressure and incident blood clots. I interpret that to mean that days with low atmospheric pressure (overcast, windy, rainy) correspond to lazy, inactive days at home. They wonder if there's a link between the low cabin pressures in airplanes and blood clots, in addition to the activity. Not sure how you would tease this apart.
I don't understand the definition of "cold-related death". Is it strictly death from hypothermia ? Is it death from seasonal illnesses, which are caused by the cold ? How far up the chain of cause and effect are we going to follow ? If a person is driving his car to work one day, hits a patch of black ice, spins out of control, and plows full-speed into a pedestrian, then did that pedestrian "die from cold" ?
>"It separates the world into a grid of 0.5 degree x 0.5 degree squares. It uses a bunch of assumptions and interpolations to get a dataset of daily average temperatures and mortality rates for each square over ten years. Then it calculates a function of how mortality varies with respect to temperature. The lowest point of that function, usually a pretty normal temperature, gets dubbed “the minimum mortality temperature” or “MMT”. Then they calculate how many extra deaths happen compared to the counterfactual where it was always the MMT, and they get five million."
It looks like they're just doing an excess deaths above the base rate type calculation based on temperature changes, I don't think they are looking at cause of death at all.
Well, yeah, but that was kind of my point. Does it make sense to just attribute all excess deaths to a single cause, such as cold ? In that case, why not the price of milk ?
Certainly not with any degree of confidence. It is just correlation. But we can all spend hours upon hours theorizing and debating.
Having lived in both extremes, some thoughts.
First, the causes of death. Heat-related causes of death are generally pretty direct; dehydration and heat stroke. They also predominantly hit the medically frail, but will also hit those with less experience with heat worse; as somebody who has lived in one of the hottest places in the country, I recognize the symptoms of heat exhaustion, and immediately rectify the situation. Somebody without experience with heat might not notice their heat exhaustion until they're too mentally addled to actually do anything about it.
Cold-related causes of death include both direct and indirect causes, however. For direct, there is hypothermia and exposure, which I think will predominantly affect the medically frail. But there are also cold-related accidents (slips/falls and traffic incidents), and also being snowed in, which can cause people to die of apparently unrelated accidents (bleeding out while waiting for an ambulance after a kitchen accident). These can be mitigated to a significant extent by appropriate local investment (snowplows, salting and sanding roads), but this is only done if it makes sense to make that investment.
For the indirect cold-related deaths, I think are notable in that they are not as limited to the medically frail. I'd hazard a guess that the average cold-related death costs far more QALYs than the average heat-related death.
Re: heart attack deaths, the paper you linked seems to be about blood thickening below a specific temperature rather than relative to local baseline. So maybe places like Stockholm are cold enough year round that people's blood isn't much thicker in the winter than it is the rest of the year?
It seems to me that the explanation about vulnerable (near death) populations is the most probable. It explains the lag time between cold weather and deaths (they get sick first) and also the tendency to be opposite in cold verses warm locations. A location that's unusually warm may help stave off a person getting sick, but a 10-20 degree temperature drop, even if the resulting temperature is well above what's needed for survival, would be enough to take their already frail body to a place where death is much more likely. In a truly cold place, that person would have gotten sick and died earlier (general death statistics regardless of temperature), or have been placed in a location where temperature differences are less of an issue - i.e. the insulation discussion, where Swedes are used to being cold and better prepare their populations for it.
In this theory, it's not acute cold that causes death, but instead lower temperatures that result in sickness and then death. Heat deaths, on the other hand, tend to be more sudden and directly related to high levels of heat, but would affect similar populations. Heat deaths come from heat stroke and other direct effects, rather than opening a person up to sickness.
Did you consider traffic fatalities in the winter? Anecdotally and from basically everybody I've spoken to, winters are more dangerous for driving due to snow, slush, wetter conditions, overcast etc.
> See also this paper, which is the closest thing to a useful summary by people with a smidgeon of curiosity that I could find in this space.
Clicking on the "this paper" link, I just see "AccessDeniedAccess denied"
That’s pretty adamant. No bang? (!)
It’s kind of fun to figure out where in the world commenters are sitting at their keyboards.
Unless they make an explicit mention of their location it’s enjoyable to see what can be inferred by their units of measure, local season mentioned, acronyms used or distinctive spelling of English words.
I am amazed by the global reach of ACX. Western Hemisphere and Eastern. Northern and Southern.
Our host has touched on how his readership has spread since his - I’m searching for neutral terminology here - let’s just call it interaction with the NYT.
No doubt it was traumatic at the time but the result sure seems like a long term net positive.
Linsey Marr recommended keeping air humid as a defense against covid but it depends on the virus for whether it prefers dry vs humid conditions. https://www.nytimes.com/2021/10/19/opinion/covid-flu-air-transmission.html
https://journals.asm.org/doi/10.1128/mSphere.00552-19
I'm wondering if that's a missing factor here. Is it less about the temperature and more about the humidity and whether it's raining? I'd be curious to see what mortality is like during rainy vs sunny periods, since that seems to correlate with temperature and could resolve the confusion about why the temperature differences for when mortality starts going up are so big from place to place.
I can't cache this out in detail, but I wonder if the odd global MMT results are partly just statistical artifacts. Like, sometimes the tails of distributions are the weirdest, least-normal parts (so maybe hottest and coldest places will break the model), and grid squares with smaller populations will have higher variance (e.g., Greenland must have a small population; thinking of that Andrew Gelman county-level rates of stomach cancer example).
I once treated someone for the beginning symptoms of frostbite in 60°F. I was so surprised I checked her several times before bringing her in and beginning treatment.
Any idea how it happened? Reynaud's?
"I find this hard to analyze because I still don’t really get why cold cities over-adapt and end up with even lower mortality than the warm ones."
Just a theory. But because cold cities *know they are cold*? Whereas in warm cities, any increase in death might either not be particularly noticed, or not attributed to the temperature - because that possibility simply won't enter citizens' or policymaker's minds. After all, they're not cold cities!
Put another way, 'cold-related deaths' are simply more salient in cities that are already cold.
"I think the idea is something like if an extreme weather event kills lots of people one year, the next year extreme weather events will kill fewer people than normal, because a lot of the vulnerable people are already dead."
I wonder if there is evidence for this from, say, bad flu seasons - or indeed covid.
Extremely low confidence explanation for some of the weirder data:
Perhaps the human body, over long periods of time, adapts to given temperature ranges? Eg, someone from Uganda might find 80 degrees to be uncomfortably cold, with some of the associated dangers, as it’s on the low end of what their body has experienced. I don’t know enough to propose any mechanisms for this, but it seems like the sort of thing biological systems would cook up.
Anecdotally, I’ve known transplants from Florida to NYC who complain bitterly about temperatures that a local person would find quite comfy (~70 degrees).
On Tibet, Greenland, etc:
Your central source (Zhao et al) didn’t collect data on mortality in the places you’re most curious about -- Tibet, Greenland, central Africa, etc. They collected data on mortality in 43 countries (see fig. 1 -- it’s mostly high-income or middle-income countries) and used that to train a model that predicts the temperature-mortality function based on “meta-predictors” like GDP/capita and Köppen–Geiger climate classification. They didn’t look at any mortality data on Greenland -- they just look at the meta-predictors for Greenland, and use that to predict the temperature-mortality function for Greenland. They use that, plus Greenland’s population and temperature history, to guess how many heat-related and cold-related deaths it has. So the lack of curiosity about Greenland isn’t because they’re ignoring a strange real-world phenomenon -- it’s because they’re ignoring the strange behavior of their model at the edges of its distribution.
Note that Tibet, Greenland, and the Andes are all in the same Köppen–Geiger climate classification -- “ET” on the Wikipedia map. It seems likely that the training data included some Andean location with weirdly high mortality sensitivity to warm temperatures, and the paper’s model generalized from that to the few other populated areas with climate classification ET. Maybe that was a good generalization! Maybe whatever is causing high sensitivity to warm temperatures in the Andes is also true in Greenland. But the paper doesn't have Greenland mortality data to test that.
Here's the map of where they collected mortality data. Note that there were a number of sites in the Peruvian Andes; none in Tibet or Greenland. https://els-jbs-prod-cdn.jbs.elsevierhealth.com/cms/attachment/71d507bb-cf6f-4641-a807-1adb64726b99/gr1.jpg
Climate classification map here: https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification
Thanks, this is very useful
Don't deserts actually cool down really quickly?
https://www.livescience.com/why-do-deserts-get-cold-at-night.html
Exposure to cold temperatures has been shown to encourage fat loss and possibly help with diabetes. There are multiple mechanisms: other than simple thermodynamics, the human body adapts to cold temperatures by producing brown fat, which consumes calories to produce more heat in order to maintain body temperature.
This could explain why people in colder climates seem to be doing better overall: they're losing more fat naturally and improving their BMIs.
This link is a decent starting point, if you want to know more you should search for Ray Cronise (a former NASA scientist) and Tim Ferriss, a health and fitness author. They were among the first to popularize this effect AFAIK.
https://www.theatlantic.com/magazine/archive/2015/01/does-global-warming-make-me-look-fat/383509/
Maybe the next survey should have a question about preferred temperature ranges.
Scott, you spend a lot of this post discussing whether seasonal effects (rather than temperature effects) are driving the cold-weather deaths. But I think the paper is trying to control for seasonal mortality effects, and just focus on the excess mortality (excess relative to seasonal trends and other trends) associated with cold (or hot) days.
“...in the first stage, the temperature–mortality association for each of the 750 locations was estimated by use of a quasi-Poisson regression with a distributed lag non-linear model… where… ns is the natural cubic spline for time with eight df per year to control for long-term trends and seasonality”
They might do a bad job controlling for seasonality! But I would be very surprised if the cold-weather mortality they observe is mostly seasonal.
Scott, you say:
> I’m not really impressed with the people working in this field. Most people don’t clearly say that excess winter deaths are a combination of season-related (from the flu) and cold-related (from cardiovascular) deaths, even though something like this has to be true.
I think the reason they don't discuss season-related stuff like flu is that they are (attempting to) control for seasonal mortality trends.
I’ve dug into this literature for a previous project. Despite the model’s strange behavior in low-population areas, my sense is that it’s probably doing a decent job estimating the temperature-mortality relationship in rich and middle-income countries. But if you want to use any of this to make inferences about the mortality cost of climate change, you need to reckon with a few other details:
The paper’s training data didn’t include any low-income countries. (See my comment on Tibet and Greenland, for a discussion of how they only train their model on a few countries.) The closest they get is the Philippines, a lower-middle-income country. (This is a welcome addition -- previous papers in this literature, like that from the Climate Impacts Lab at Chicago, only used upper-middle income countries like China and Brazil.) From what little data we have, it seems like infant mortality is much more sensitive to high temperatures in low-income countries. (See https://www.nber.org/papers/w24870. This makes sense: if you can afford any climate control -- a swamp cooler, a neighbor’s cellar -- you use it to protect infants on a hot day. So infant mortality is a lot less sensitive to heat in lower-middle income countries than low-income countries.) So, if you use this paper to estimate the effects of warmer temperatures on mortality, you’re going to miss a lot of infant deaths in low-income countries.
The papers you’re citing combine deaths across all ages. But the excess deaths on cold days are concentrated among the elderly, whereas infants disproportionately die on hot days. (You can get this result by playing with the data from the appendices of this paper: https://www.nber.org/papers/w27599) If you care more about the death of an infant than an elderly person, then this pattern will significantly increase the net mortality costs of warmer temperatures.
When economists try to turn these temperature-mortality functions into a “mortality cost of carbon”, they often assume perfect adaptation -- i.e. if temperatures in Delhi start to look like Kuwait City, well then everyone in Delhi will live like people in Kuwait do. Never mind that they may not be able to afford the air conditioning that makes Kuwait livable.
And then of course, none of this captures the mortality cost of stuff like climate-induced migration. Desertification of the Sahel, flooding in Bangladesh -- those are going to drive migration and conflict, and those mortality costs will be significant too.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3606398/ has some data on hypothermia in infants which suggests that infant mortality rates in poorer countries may in fact be quite sensitive to cold temperatures, with effects on mortality up to 28 days after the observation of hypothermia. See in particular the section on environmental correlates with infant hypothermia.
"Why would cold places adapt so hard that they did better than warm places? I don’t know, but this is what everybody says."
Adaptations aren't continuous, they're discrete - e.g. if you already have a heating system, if it gets extra cold you can turn the heat up a little more, but if you have no heating system you will die.
> When you’re skeptical of complicated models, sometimes it helps to go back to the rawest data you can find. So here’s a graph of mortality rates in New York City over time.
But that's not the rawest data you can find. The rawest data is the number of people in New York City before checking what rate they're dying.
> If growth mindset was so great, you would expect fixed mindset people at Stanford to be as rare as, say, people with less than 100 IQ are at Stanford. Given that you will search in vain for the latter but have no trouble finding a bunch of the former for your study on how great growth mindset is, it sure looks like IQ is useful but growth mindset isn’t.
But I would drift one degree away from the rawest of data, because there's an elephant in the room: wealth. You talk about "cultural adaptation", but a lot of "cultural adaptation" is pretty obviously only posssible with large amounts of wealth.
> The worse your climate, the more likely you are to have good central heating.
Good luck having good central heating without wealth.
> Stockholm doesn’t get any increased mortality from the cold, no matter how cold it gets. Plausibly that’s because they’ve organized their lives and built environment around surviving cold winters.
There are a lot of people in Stockholm. But Stockholm is very wealthy. If Stockholm were not so wealthy, they would not be able to sustain so many people in such a hostile environment.
> I’m not entirely convinced by this story. Shouldn’t this mean that everywhere has the same level of excess death from the cold? Why would cold places adapt so hard that they did better than warm places? I don’t know, but this is what everybody says.
Cold places adapt better to everything. And yes, cold places really do adapt so hard that they do better than warm places. And the reason for that is because having a large enough population to be studied, in a cold place, is very very very strongly correlated with wealth. Cold places, or rather, the people *in* cold places, are wealthy, and wealthy people adapt better to any environment.
And why are large populations in cold places necessarily so wealthy?
There are places on Earth that reached large populations despite lacking great wealth. All such locations have one thing in common: they are warm.
This patterns *jumps* out of the data. You will search in vain for cold regions that reached large populations before acquiring large amounts of wealth, but warm regions have no such difficulty.
The one thing we can say a priori about the winter death rate in New York is that it can't possibly be very bad, because if it was, then there wouldn't be so many people in New York.
Which is a more dangerous location for children to play: a backyard swimming pool, or an interstate freeway? Well, many children die each year playing in swimming pools, and very few playing on interstate freeways. Therefore swimming pools are more dangerous. Do you see the obvious problem with this logic? The reason there aren't so many children dying while playing on interstate freeways is because there aren't so many children playing on interstate freeways. And the reason for that is because interstate freeways are so incredibly dangerous.
The death rate for interstate freeways looks pretty good, only because the population the death rate is measured among (adults in cars) includes none of the relevant vulnerable population. Because the relevant vulnerable population simply can't be found in any great numbers at that location. Because it's too dangerous.
Rich people are going to be fine anywhere. (Stockholm doesn’t get any increased mortality from the cold, no matter how cold it gets.) The relevant vulnerable population is poor people. Poor people simply can't be found in cold places because cold places kill poor people too reliably for a not-wealthy population to grow.
> The lowest recorded temperature in Kampala, Uganda was 12C (54F). Who’s dying from that?
Have you tried to live at 54F? Actually tried? It's really hard! That's why you don't have your thermostat set to 54F. It wouldn't kill *you*, because you're a wealthy First Worlder, but if you're so poor that survival isn't a given, "everything in life is harder" has a lot of knock-on effects.
Christopher Moss has details on some of the ways that people in cold places are using large amounts of wealth to adapt to the environment.
The part I take from it is that adaptations using wealth are more effective everywhere, and the main difference is that large poor populations that can't afford electric heating and must use open fires simply don't exist in cold places. Because populations without wealth cannot grow large in those places.
Thanks for pointing out this selection effect, which is obvious once you become aware of it. Entertainingly written as well.
It sort-of implies that if we could make Africa richer, Africans should be better able to deal with global warming (=increased hazard), since they will have more resources to adapt, so that the negative consequences of global warming (=vulnerability) diminish . (Risk = hazard x vulnerability again.)
I don't know whether it's that we can make Africa richer or whether Africans can make Africa richer.
...or both...
Thank you, but the point I was trying to make was different. Figure there will always be someone left behind, for some definition of "left behind" (their lives are different from their ancestors', but not better). Those are the people who lack the wealth for the really good adaptations. The question is, what climate is least hostile?
I claim you can answer that question by looking at where most poor people were in fact living, say, a hundred years ago. Recently things get complicated by two problems: birth control, and people rising out of poverty. (Uh, I mean, that's a good thing, but it's a problem in the sense that it decouples population from the hostility of the environment. Efforts to lift people out of poverty make the poor population shrink, not because the environment is getting worse, but because poor people are being converted into non-poor people.)
There's obviously a lot of noise in the data: some places have much smaller populations than other places with seemingly similar climates. But there's also an unmistakable pattern.
We could call that the real "minimum-mortality temperature", the kind we actually care about. But it's not like there's a spike at any particular temperature. Based purely on eyeballing with a vague idea of where most people were living, India had a large population in one of the hottest parts of the world, while most poor Chinese were not actually living in the hottest parts of China. What we really have is kind of a smear over the upper side of the temperature scale.
It's hard to say, at the upper end, when humans start failing-to-thrive due to too much heat. Obviously it has to happen at some point below the temperature of Venus. But given the amount of noise in the data, I wouldn't trust anything except a stark difference we can see with the naked eye. Like, clearly India is less hostile than Siberia. But I don't feel confident saying anything about hotter-than-India. There just aren't a lot of places with higher average temperature than the hot parts of India. (There are places with higher temperature extremes, but they're deserts, and deserts are obviously hostile for unrelated reasons.) Some parts of Africa were a little bit hotter than India, but the parts of Africa that were the same temperature as India also had smaller population, so..."unrelated regional variation". Similarly other places with the same temperature as China had smaller population. There's just too much noise.
Even if you can hunt up a few places on Earth where the problems of heat exceed the problems of cold (not obvious: even in places you think of as scorched deserts, people burn dung to keep warm for lack of any other fuel), it seems obvious that putting a warm coat on the Earth will be a good thing on most of the Earth and a basically-neutral thing even in most of the warmer parts. (If the increased temperature was due to increased insolation, that would cause problems of its own, and of course the fact that the warm coat is carbon dioxide might cause problems of its own, but the warm coat itself seems like obviously a good thing.)
The claim is that Bressler and Heutel/Miller/Molitor and so forth are garbage-in-garbage-out because the numbers they're looking at aren't the numbers that matter. When you look at mortality rates, you're looking at populations that are large enough for you to measure mortality rates, so you're looking at people who do in fact live in the region and grew to large populations. To the extent that there are variations in current-year mortality rates, it's noise. The reliable numbers are the compounded mortality rates for *all the previous years*, which are baked into the population numbers, but more particularly the size of the population-without-wealth, though that's harder to measure.
I would also point out that this is fundamentally a problem of maximizing population. There's a certain population of people who lack the wealth to adapt well. A "pool of susceptible individuals" to use the Auliciems terminology.
By 2100, all of the current members of the pool of susceptible individuals are going to be dead, but we will have new susceptible. (Well, "we", won't, see above re: by 2100 everyone dead, but they'll exist.) We want to maximize the size of the pool of susceptible individuals...sort of. That number also shrinks when people rise out of poverty, which is obviously a good thing. But we want to maximize the population that they theoretically could grow to absent all the good reasons for that population to shrink.
When in Saudia, I had a long talk with a German organ-transplant-surgeon. He said the declared "causes" on "certificates of death" are a bad joke (at least in Germany): if one dies at home, a doc (usu. GP) takes a quick look and writes: sth. sth. heart-attack. Which thus ends up meaning: "no idea, really, but does not look like murder" (in hospitals they will usu. at least have a clue, what to suppose). "Cardiovascular" is the default diagnoses, without much if any value.
There might indeed be many, many more "flu-related"(as in "corona-related") deaths than the records show. Esp. among the frail.
Saudia (Kuwait): - death among "true" Saudis should not show much seasonal fluctuation - they spend 99% of the day in ac-cars, ac-houses, ac-offices, ac-malls. AC usu. put on max. power. (They may go out for a picnic in the cooler months, they do not use "crowded transport" all year). out I had to wear a jacket in office, it was just too cool without. South-Asian workers there (building!) at 50C in the scorching sun: sure, they should show higher mortality in summer. Statistics from this region need to be at least double-checked (90%+ of people in Qatar are not Kataris).
Last: DANKE! I wondered about this heat-cold-deaths for a long time, now I can wonder much more profoundly. - Why even with central heating a day in winter kills 40% more than a day in summer - yeah, one might think that is relevant enough to study till we know.
So basically the Winter-Death correlation is huge, but not empirically related to temperature itself. I suppose someone needs to come at it sideways by crunching data on non-temperature variables to try to tease out their separate effects. For example, randomly:
1. Does the winter-death phenomenon exists even in, say, Quito, Peru which is on the equator and literally has the same temperature and sunlight all year round. https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,Quito,Ecuador If Winter-Death exists in Quito, what are the categories of excess deaths that increase in Winter?
2. How does altitude affect the winter-death connection? For example, you could hold geographical region constant while comparing temperature fluctuation if you compared the winter death rates in tropical African areas with colder high-altitude locations nearby (does anyone live on Mt. Kilimanjaro?) Do high-altitude, low latitude death rates correlate more with geographical region or places with similar temperature fluctuation?
3. Do hours of light and dark separately correlate with death rates? Are there seasonal fluctuations in hormones, Vitamin D production, sleep patterns, etc. that could be explanatory?
If someone really cracks this extremely non-trivial issue you've identified it might be a Nobel-worthy event.
1. What are you defining as "Winter", at that point?
For present purposes, as the season when death rates spike, per Scott's article. I can't remember if he referenced what happens to death rates in the Southern Hemisphere. But I believe their flu season and death rate spikes are during "their winter."
Oops, now I see you were referencing Quito in particular (meant to say Ecuador not Peru, btw). But that's the whole point of looking at the data - what will it show for a place that literally doesn't have any seasonal variation in temperature and light. (Although rainfall apparently differs).
According to Wikipedia: "There are two seasons in the city: dry and wet. The dry season runs from June to September and the wet season is from October to May."
There are a number of comments speculating that different populations may have different genetic adaptations to environmental conditions.
No need to speculate.
I recommend this review: "The Genomics of Human Local Adaptation", Jasmin S. Rees et al, Trends in Genetics, June 2020.
There are lots of excellent references within the paper that people can then follow up on.
Here's the abstract:
"Modern humans inhabit a variety of environments and are exposed to a plethora of selective pressures, leading to multiple genetic adaptations to local environmental conditions. These include adaptations to climate, UV exposure, disease, diet, altitude, or cultural practice and have generated important genetic and phenotypic differences amongst populations.
In recent years, new methods to identify the genomic signatures of natural selection underlying these adaptations, combined with novel types of genetic data (e.g., ancient DNA), have provided unprecedented insights into the origin of adaptive alleles and the modes of adaptation. As a result, numerous instances of local adaptation have been identified in humans.
Here, we review the most exciting recent developments and discuss, in our view, the future of this field."
>But then why don’t we see any effect from excess winter heart attacks in very cold places like Stockholm or Siberia? Overall I’m not convinced of this one either.
Selection? This would be extremely interesting to study (genetically or epigenetically).
Selection effects are the most powerful force in the universe.
It's not the cold - it is the UV light that is missing in winter.
A whole host of physiological processes are dependent on UV light, vitamin D synthesis being the best known. But also nitrous oxide synthesis, lots of weird immunology and neurology are affected.
All the studies looking at excess winter deaths are the same as the ones looking at increased mortality from low vitamin D - they are measuring a surrogate for low UV exposure.
As a result, I expect global warming to be a net benefit as less clothing will being worn, hence elevated UV exposure.
Forgive me if this has been covered in the many, many comments below, but:
My understanding as to why flu is more prevalent in colder weather is that 1) sunlight kills germs, and there’s less sunlight (and people go outside less, which is perhaps the more important factor) in the winter, and 2) viruses don’t like humidity (for reasons I don’t quite understand). These at least seem to be the popular theories, and I would think that they at least deserve a mention, if only to dismiss them.
On a separate note, I’ve gone from “global warming will decrease cold deaths less than it will increase heat deaths” to “I’ve heard that that’s not true, and so now I don’t know,” to, now that I’ve read this article, “it looks like cold and heat deaths are mostly about human adaptation or lack thereof, so there’s no real way to tell what the effect will be—probably very little, but, as always, worse in poorer areas."
That's a good summing-up.
I meant “I’ve gone from ‘global warming will decrease cold deaths *more* than it will increase heat deaths’."
Ah, it was a slip of the pen? (I would not have been surprised if you held the opposite prior, since it is rather common to assume that global warming will cause more deaths than it saves - including in the article Scott links to ("Discussion" section). That's from all effects combined, though.)
I make no predictions on all effects combined, though it’s certainly plausible that it will cost more lives than it saves. But yes, my original belief, years ago, was that due to the prevalence of cold deaths, that it would—on this front—be a net benefit.
I would not be surprised if your last statement may turn out to hold also in the general case: "it looks like positive and negative effects of global warming are mostly about human adaptation or lack thereof, so there’s no real way to tell what the effect will be—probably very little, but, as always, worse in poorer areas."
Agreed.
>The lowest recorded temperature in Kampala, Uganda was 12C (54F). Most years it doesn’t even get that low! Who’s dying from that?
Ok so it's clear you haven't been to Kampala in the winter, because 12C when it's usually >35 is absolutely freezing. The people in Kampala are certainly all wearing mittens and fur coats when it's 12C; I spent a couple of months in a similar place and if it reached 12C that was bad. Not only that, but 12C without heating at night is even worse. If you don't have super warm blankets and try to sleep in an unheated house as 12C you will certainly get sick. Add to that the fact that if it's 12C at night it might still be 35C in the day a few weeks later. The sudden temperature swings are what people say triggers the flu wave; not sure if true but certainly seemed plausible.
Edit: ok so apparently Kampala doesn't actually get hot, my comment applies to places that are usually hotter. I can confirm from my own experience that 12C feels absolutely freezing if it's usually warmer.
I know it's probably impossible to measure well, but whenever I see something like this, I always wish that we could get a measure of QALYs rather than deaths.
Because if it's like 'these terminally-ill bed-ridden 90+ year-olds are going to die from something in the next year or two, and it turned out to be becaus their hospice nurse was 20 minutes late because of snow on the road', then my reaction to that is very different from 'healthy people in the prime of their lives get freak heart attacks from constricted blood vessels when otherwise they would have lived another 50 healthy years'.
Extremely related, just came out:
https://direct.mit.edu/rest/article-abstract/103/4/740/97668/Adaptation-and-the-Mortality-Effects-of?redirectedFrom=fulltext
Very interesting. A suggested wider take at https://wordpress.com/post/phenell.wordpress.com/6516
> I find this suspicious, and I wonder if there are a bunch of less obvious seasonal viruses going around causing deaths that don’t get recorded as “seasonal viruses”. Or: we know that sometimes people can get strokes and heart attacks as complications of the flu - maybe we don’t notice the flu, or coroners don’t record it, and it just gets marked as a stroke or heart attack.
I had exactly this discussion with my partner who is a doctor. I had been speculating that our increasing understanding of COVID complications like strokes, clotting, heart attacks, etc. likely indicates that there are all sorts of complications with other common illnesses that we never studied deeply enough noticed before, and so we may have underestimated those numbers for years. Comparing like vs. like against COVID will be a shifting game for years if this is true.
Unfortunately this will also probably be used as justification by both sides of the lockdown debate.
I think you are on to something with extreme weather, as it is experienced locally, being the culprit. We had a bad heat wave in Oregon recently and a lot of older people died. It was even worse in British Columbia.
It wasn't the old people who needed to be cared for by other people who died. The victims tended to be independent old people who lived alone. My mother is really old, but she grew up in the tropics and rolled her eyes at me when I gave her advice about how to keep cool. She was fine even without air conditioning.
It was pretty hot, but I doubt if comparable heat in the Deep South would have had the same impact. A lot of the harm of extreme weather is going to fall on frail people who don't know how to cope. A young, fit person can deal with stress that will kill an old person. It will suck for them, but they'll live. Old people don't have the same margin of error, and if they don't have the experience to deal with the weather event they are far more likely to die.
There are a lot of simple things that people do every day that are taken for granted, but in aggregate they matter a lot. I think many lives could be saved by educating people who have narrow margins for survival how to survive rare events.
As for winter being a problem in tropical countries... I'm not sure about the flu being the culprit. What's the weather like during winter? Does it rain more? Does it flood? I'm with you on the temperature not being the cause but correlating with something else going on.
That excess winter death graph you have is interesting. The Netherlands, Belgium and France are right next to each other, but their data points are very far apart. Half of Belgium is Dutch, the other half is French, so IDK what the hell is going on.
Can somebody explain what the "minimum monthly temperature" means in the plot? Because I'm from Portugal and I'm sure it gets well below 10C there in the Winter...
I think it means that the coldest month has an average temperature of 10 C.
One possibility is that people choose to rest during periods of "aberrant" temperature (heat in the tropical regions, cold in the cold regions). While you are resting (sleeping, siesta, whatever) at home, you are LESS likely to die.
So, the actual effect may be that cold death rates in sub Saharan Africa are "normal" and heats results in lower than "norm" death dur to lack of exertion. The opposite with heat in the cold regions.
Just another (possible) way to frame the data.
SB
This is a good point. The relevant vulnerable population is not just poor people, but poor people who are physically active right this moment. (Physical activity decreases mortality over the long term in rich sedentary populations, but in any populations it increases mortality in the short term.)
I still think by far the biggest effect at work here is that certain kinds of people simply fail to live in certain hostile environments in the first place, but it is also true that when you zoom in to a day-by-day basis, the population of "physically active poor people" decreases on particularly hostile days. (Not to zero; there are always exceptions like Arabian skyscrapers on tight schedules. But there are fewer people active, and fewer active people means fewer deaths.)
Maybe influenza (and other seasonal viruses) are cyclical by nature (evolution/mutation load in ARN viruses together with group immunity can lead to that, in a typical cyclic predator/prey dynamic), so a rather weak and local periodic signal (winter in the more densely populated regions for example) will act as a sychronizing clock to the inherently non-linear cyclical epidemy. This signal can be weak, with period variation, even skip a beat from time to time, while the response stay strong with a more stable period than the trigger...
This is also a postulated mechanism for global climate periodic variation (glaciation, oceanic cyclic oscillations), and quite a convincing argument on how relatively stable periodic phenomenon occurs seemingly out of nowhere...
Surely it's all the indirect reasons that are most accountable. From what I understand, 'crop yield down -> guy somewhat poorer -> more stressed and heart attack' would also get captured by their function.
Yeah in a way it seems to say that "people die less under usual conditions, more under abnormal conditions". I have the feeling we could do the same with a bunch of other variables and you'd always end up with the minimum of mortality around the "usual" value of the variable for the region.
I tried discussing this on r/AskScienceDiscussion a few months ago: https://www.reddit.com/r/AskScienceDiscussion/comments/ns0qnr/recent_study_estimated_the_number_of_extra/. A few take aways:
- The estimations of the number of deaths due to Climate Change are dominated by deaths due to malaria and famines, both of which seem preventable by non-climate-related methods, i.e. better treatments for malaria (which are being worked on) and either some economic or humanitarian measures to mitigate the effects of localized droughts.
- Even if you consider the deaths from hypothermia alone (which are definitely cold-related -- it's there in the name), you'll end up with at the very least 50000 death per year, probably more, which is higher than the number of deaths from heat.
- That said, it is not clear how climate change will affect hypothermia, because deaths from it occur during unusual cold spells, and their frequency and severity may actually be increased due to climate change, because it increases the variance in weather events.
Isn’t the seasonality of the flu mostly due to solar radiation?
For example, the reference amount of sun (Philly, noon summer sun) kills covid-19 samples at an exponential rate of 90% every 6.8 minutes. https://academic.oup.com/jid/article/222/2/214/5841129
UV sources;
https://www.cpc.ncep.noaa.gov/products/stratosphere/uv_index/gif_files/diurnal.gif
https://www.cpc.ncep.noaa.gov/products/stratosphere/uv_index/
So there’s a clear hypothesis why warmer places have higher winter mortality; they get a similar variation in UV light, plus the warmth is good for bacterial and viral growth and survival.
It will be funny if it turns out that banning CFCs to fix the ozone hole was a net detriment for public health.
I mean, too much sun ain't great for us either! Per NOAA, that Philadelphia reference amount of sun will (on average) give a white person without a tan erythema (a burn) in 14.5 minutes. In Hawaii it's 13 minutes and 23 minutes on Nunivak Island, Alaska.
https://www.ncbi.nlm.nih.gov/books/NBK304366/?fbclid=IwAR1TY2u2ZCx238C1B9mRgbZYhX3_GGWw4S__Auq6XEdh9xN3I-KuwkCopOI
Acute exposure with tanning acclimation is particularly bad for people, although a tan still only gives limited protection - but seems to be at an efficient point with respect to all kinds of skin cancer for people who are chronically outside. The people who are most at risk are office workers who then go to the beach in the summer without any tan. (For best results, begin in the early spring and slowly and carefully build up a tan. Getting a burn in order to tan quickly exposes you to the same cancer risks you're otherwise trying to avoid.)
So even ignoring all the health effects of the ozone hole that aren't directly radiation, our radiation tolerance advantage is probably most pronounced at relatively low UVA and UVB levels, and is minimal against UVC.
In spring 2020 my parents bought a lizard light; they put incoming mail and packages under it for a bit as a relatively human-safe covid precaution. I forget if it was in the spare bedroom or the foyer but it was a place where the mail was for much longer than people, compounding our dose-safety advantage over any hitchhiking viruses.
One possible (partial) explanation for the unintuitive effects is that a lot of the investment/infrastructure that reduces weather-related mortality-- heating, air conditioning, social norms that reduce time spent outside in poor conditions-- aren't really about mortality. They're about enjoying life and being comfortable. So sure, warm places might invest more in AC and maybe won't invest in good insulation and back-up heating systems. And as a result, they'll be more susceptible to mortality to cold than heat. But they weren't trying to equate the marginal cost of mortality prevention across hot and cold days... they were trying to equate the marginal cost of *enjoying life*. Growing up in a cold climate, the first even remotely warm day of May, my parents would take my brother and I to the lake and we'd exhaust ourselves swimming in the frigid water. Later, in college, that same warm May day would be an occasion for excessive binge drinking on our outdoor couch. Beach-going and alcohol are probably bad for maximizing life expectancy, but certainly good for something.
Some related observations:
1. Deaths in tropical EU are practically not seasonal. Below is a chart I made for covid tracking reasons for Overseas Territories of France, the gray line is the average of weekly deaths in 2016-19.
2. Most of the studies I have seen uses daily average temperature. Maximum and minimum may be more relevant. For example, without air conditioning a lot of people have trouble to have a good night’s sleep when the minimum is more than 24C.
3. Climate/weather is more than temperature: for example, weather fronts are known to have large health effects, and weather fronts can be seasonal. Also, wet bulb temperature can be very different from actual temperature.
4. There can be a lagged effect of cold/hot weather, with some kind of accumulated damage/depleted resources (vitamin D, other vitamins etc.). The post mentions it, but it can be even longer lasting than just the extreme weather spell (there could be a decline throughout winter).
5. The ultimate question is whether apart from seasonality, overall mortality is lower in places with “better” climate (this may be difficult to define). There are many confounding factors, income, smoking etc., but within the EU at least, there is some evidence that the further South a location is, the higher is life expectancy (there is data for NUTS2 regions). The Madrid region has the highest life expectancy amongst EU regions. Corsica, Caribbean islands of France are pretty well placed too. In the detailed data though, as far as I remember, this results mainly from lower cardiovascular and cancer deaths – it would be a very important area to study.
6. There is a large difference between life expectancy of US regions and EU regions (latter is typically higher), if anyone has studies that compare seasonality, please link it here (i.e. is it mainly excess winter deaths, or is it higher all year around).
Sorry, it seems I cannot paste pictures here
I agree that understanding lagged effects is really important and somewhat missing in the current lit. For one-- they would give a much better picture of how much of this is just temporally shifting deaths vs new deaths. Plus, it would help understand climate characteristics that lead to better or worse health, even if the death is ultimately attributed to a non-weather cause.
> Why would cold places adapt so hard that they did better than warm places? I don’t know, but this is what everybody says.
> I still don’t really get why cold cities over-adapt and end up with even lower mortality than the warm ones.
(I'm confused by the overall picture too.)
That's probably because many of these adaptations are discrete, not continuous. There's a certain cost in turning the heating slightly up or down (which is continuous), but the main cost is setting up the infrastructure. If you have 80% of the pipes needed for central heating to work, you don't have 80% of the heating, you just get a plumbing mess.
Are we dismissing the idea that temperatures that seem moderate to you are highly uncomfortable for people born in a different area? -- so I imagine the people are adapted to that temperature, and they function less well in other areas. There's long term and short term adjustment -- apparently stuff like the number of sweat glands you have is calibrated based on how hot it is for your mother when you're in the womb; other stuff is multi-generational adjustment.
But anyways, just anecdotally, I know people from much colder climates and much hotter climates who self report as being less comfortable and less healthy whatever they do. Even if you cover up, you're still having to breathe in a lot of cold air all the time if you're from a culture where covering your face is weird (or maybe with covid, that taboo has been busted?); but it's self-reported so who knows.
Separate question: how do we deal with the issue that death is inevitable when looking at these numbers? I've always wondered about the fact that presumably above a certain age, when death is inevitably just around the corner and you only need to make a mistake -- if causes of death are zero sum: reducing the number of deaths from falling down the stairs has to be balanced by deaths from some other source, because it's inevitable -- modulo extending someone's life by a year. I guess this is why people focus on deaths to youngish people?
If you are a stranger in Florida on an epic hot / humid day you are surrounded by people who are experts in surviving that climate with the necessary infrastructure to survive. If you show up on a very rare epic cold day you surrounded by idiots who don't have a clue what to do.
Is Florida no longer full of Yankees? My dad grew up there and he said you could tell how long people had lived there by how old their coats were.
Law of Small Numbers? Greenland has population ~ 60,000. Extreme results are more prone to come from small samples.
> The lowest recorded temperature in Kampala, Uganda was 12C (54F). Most years it doesn’t even get that low! Who’s dying from that?
Try being in that temperature without proper clothes. I am pretty sure that it is enough.
I was sleeping in test 12 C with clothes for 16 C and it was miserable. I would not be surprised by frail person with clothes for 26 C dying.
And poor weather to that like rain or wind and lack of high quality tent and add illness/malnutrition on top of that. And I would be even less surprised.
test -> tent obviously
Many years ago I remember (anecdote alert) that the radio news reported that missing persons were often found dead in the countryside, and to have died from 'exposure'.
It's quite possible that people who are warm in the day through activity, climate, or shelter nonethe less die of 'cold' or 'exposure' overnight because of the reduced activity and shelter even if the temperature is not absolutely cold in temperature terms. I imagine that people in Africa might find the nights lethally cool if there was no cloud cover or shelter.
FWIW
Hyperthermia death
https://www.washingtonpost.com/nation/2021/10/21/california-family-dead-hiking/
Birds carry the Flu viruses, so perhaps the cause are migrations, not the weather.
Yes, exactly what I was thinking. That fits the data nicely.
In extremely poor regions of South America and Africa, it happens that people die in winter during sleep because they use charcoal for heating and get suffocated.
If HxNy were the only flu strain, we would approach herd immunity within several years, even through a cold winter. So the flu continues to mutate into different strains to evade immunity, and one of the major unmentioned factors here is this strain churn, means a (in reality, a set of dozens of) different strains circulates through populations each year. The consistent cyclicality of flu season is largely driven by strain churn, but that still doesn't explain the peak/trough and their correlation to seasons.
I'd speculate summer as the selection bottleneck in highly seasonal regions, and winter as the exponential part of infection S-curve of a novel infectious agent. So: it's summer is northern Eurasia, and the living is easy, except for the immuno-compromised. Which strain is best able to make it through the summer? This is largely driven by which strain does the immune system have the least memory of. And since the immuno-compromised are usually old, this is perfect for finding something most other people have never been exposed to either.
Now it's September, and the flu has faced a 99% mass extinction event - especially around the previous year's strain where R0 is approaching less than one. Whichever funky new (so old, it's new) strain was able to hang on and continue to infect is going to well poised to spread through the rest of the population. Through travel, hajj's, agrarian laborers etc, these selected for strains again move throughout the world causing another peak. Immunity to the new strain builds, and then we do the summer selection process all over again.
"We still don’t really understand why the flu is seasonal."
Is anyone looking into migratory bird patterns? I'm surprised that the Wiki article didn't even mention those as relevant.
Waterfowl like ducks are reservoirs for influenza strains and migratory birds are known to be important to influenza's evolution and spread.
"Virologic surveillance of apparently healthy birds has established that the waterfowl of the world are the natural reservoirs of all known influenza A viruses. The Anseriformes (waterfowl) and Charadriiformes (shorebirds and gulls) are the major reservoirs in which the 16 HA and nine NA subtypes are perpetuated"
https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.0030167
A common chain of transmission is that a virus will spread from migratory birds to farm-birds like ducks to farm birds like chickens sometimes passing through pigs and finally to humans.
It seems notable that the % overall excess death ratio reported in the Zhao et al. study throws up the most extreme and counterintuitive results in areas where the study's data is very poor and the temperatures are very extreme. It looks like they only had daily time-series data on mortality for 43 countries and extrapolated their mortality rates for all other areas based on factors like GDP/capita and daily temperature ranges. Some areas in sub-Saharan Africa and central Asia have extrapolated excess death rates (for counterintuitive causes of death) as high as 20-25%, which is WILD, and these areas seem to correspond with a) a lack of daily time-series mortality data for that location b) low GDP/capita and c) extreme local temperatures. It's possible that these simply ARE the conditions under which extreme counterintuitive mortality rate increases occur, but it feels much more like a model being left to its own devices and getting a little wibbly around the edges when the data is spotty.
(It's also worth noting that the scales on the map of annual average heat related deaths in Fig. 3 look suspiciously data-crime-y, but that's more of a procedural quibble than a criticism of the article. I bring it up here because without paying attention to the scales of the graphs it looks deceptively like the rate of heat related deaths for Europe [where there data is good] is very high.)
I find myself mulling over whether there is any correlation between the average wealth of a culture, and the rate of deaths related to either extreme cold or extreme heat. But I also am trying to figure out how pre-industrial cultures and civilizations dealt with extreme weather.
Do we have good data for deaths due to extreme weather among the Dorset people, or Icelandic settlers, in Greenland 1000 years ago? Between the two groups of people, I would suspect that the Icelandic culture was slightly wealthier. Did this affect survival rates during the transition from Medieval Warm Period to Little Ice Age?
What about the Thule people, who replaced both groups in Greenland? Were they wealthier, or not?
If any of these three groups had a better ability to survive in climatic extremes, it was more a product of culturally-learned behavior than of genetics or economic success.
I suspect that this pattern shows up in many of the examples cited for deaths due to hypothermia during a cold snap in warm climates, or deaths due to heat stroke in a cold climate. If the problem hasn't shown up often enough to generate a cultural story of what not to do in that scenario, then the likelihood of a person choosing to do something foolish increases.
The wealth of a culture can put a layer of protection around a person. It can reduce the need for the transmission of cultural knowledge. In some cultures, it was the knowledge about how to keep warm sleeping on the ground. In other cultures, it was the knowledge about how to keep cool when the temperature stays hot all day and night for many weeks on end.
Sorry, I didn't read all the comments, and certainly someone else mentioned this - so apologies to them, but I think you're looking at this the wrong way. You finally touch on this at the end of the article, but you use the word "because" as it relates to death which I believe has distorted your thinking. People don't die "because" of the flu, the heat, the cold, etc. People die. (hard period). However people die * sooner than we might like * "because" of the heat, cold, etc. So, the only stat that makes sense and what you need to look at is Years of Life Lost (YLL), or better yet Years of Quality Life Lost. Deaths will go up short term during the cold and heat, but a careful analysis should (perhaps) look at the annual death rates and see if during a year with higher than average temperature in a region the annual death rate has increased. I'm not saying it's not a tragedy when a certain percentage of the population dies 6 months sooner than they normally might, but that doesn't have the same implication as "10% of all deaths are due to cold".
One problem with "hot cities have worse life expectancy" is that hot cities also have lower income and otherwise differ demographically.
If you look at North America and Europe, the most affluent countries are in the north, and the poorest are in the south. Moreover, further north in the US, there are generally fewer black people on average, and more Asians, and blacks have higher mortality rates than whites do while Asians have lower mortality rates and live longer.
Hawaii - a tropical state with very few black people, but enormous numbers of Asians - has the highest life expectancy of any state. California, which has a lot of Asians and Hispanics (both of which have above-white life expectancy in the US) has the second highest life expectancy, despite being a hotter state. Indeed, the US north/south cline is mostly because of the South, which is also extremely obese, which is likely another significant driver of the trend.
As such, this really seems likely to be a "richer places live longer" thing... which makes the trendline completely worthless. The rich places that are pretty hot - like Hong Kong and Singapore - have quite long life expectancy, and Australia, which is also a pretty hot country, also has a good life expectancy. These "abnormalities" are simply the result of there not being many developed regions in hotter areas of the world.
And with regards to mortality rate increasing over the 21st century, this is goin to happen regardless of global warming, because the population is getting older on average because people are having fewer kids. So it's kind of worthless to project that mortality rates are going to rise, because no matter what we do, they're going to go up simply because there will be a higher percentage of old people in the population, especially in developed countries.
Okay, simple correlation: more exposure to sunshine = higher serum Vitamin D3 levels. Countries that consume a lot of fish/fish oils will have consistently higher levels of Vitamin D3 during periods when the population has lower exposure to sunlight. Higher levels of Vitamin D3 provide higher levels of protection against diseases and blood clotting/strokes/heart attacks.
Lancet article says: https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(21)00081-4/fulltext tl;dr: "Globally, 5 083 173 deaths were associated with non-optimal temperatures per year, 9·43% of all deaths were cold-related and 0·91% were heat-related). ... Eastern Europe had the highest heat-related excess death rate and Sub-Saharan Africa had the highest cold-related excess death rate. ... From 2000–03 to 2016–19, the global cold-related excess death ratio changed by −0·51 percentage points and the global heat-related excess death ratio increased by 0·21 percentage points, leading to a net reduction in the overall ratio." - Cheers, global warming for saving millions from premature death this century! Ahrrg, "millions" - so it's just statistics ... :(
theory that flu cases rise in the winter due to people spending more https://www.scholarshipbundle.com/2022/02/list-of-fully-funded-phd-programs-2022.html
Influenza virus prefers cold temperatures and low humidity. https://www.scholarshipbundle.com/2022/04/queen-elizabeth-commonwealth.html
Influenza virus prefers cold temperatures and low humidity. https://www.scholarshipbundle.com/2022/04/sydney-scholars-awards-in-australia.html
https://www.scholarshipbundle.com/2022/03/clean-government-scholarship-2022-23.html
https://www.scholarshipbundle.com/2022/03/eui-young-african-leaders-program-2022.html
https://healthy-structure.blogspot.com/2023/03/how-to-get-rid-of-keloids-keloid-scar.html