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Will climate change bring benefits from reduced cold-related mortality? Insights from the latest epidemiological research

Filed under: — stefan @ 11 June 2018

Guest post by Veronika Huber

Climate skeptics sometimes like to claim that although global warming will lead to more deaths from heat, it will overall save lives due to fewer deaths from cold. But is this true? Epidemiological studies suggest the opposite.

Mortality statistics generally show a distinct seasonality. More people die in the colder winter months than in the warmer summer months. In European countries, for example, the difference between the average number of deaths in winter (December – March) and in the remaining months of the year is 10% to 30%. Only a proportion of these winter excess deaths are directly related to low ambient temperatures (rather than other seasonal factors). Yet, it is reasonable to suspect that fewer people will die from cold as winters are getting milder with climate change. On the other hand, excess mortality from heat may also be high, with, for example, up to 70,000 additional deaths attributed to the 2003 summer heat wave in Europe. So, will the expected reduction in cold-related mortality be large enough to compensate for the equally anticipated increase in heat-related mortality under climate change?

Due to the record heat wave in the summer of 2003, the morgue in Paris was overcrowded, and the city had to set up refrigerated tents on the outskirts of the city to accommodate the many coffins with victims. The city set up a hotline where people could ask where they could find missing victims of the heatwave. Photo: Wikipedia, Sebjarod, CC BY-SA 3.0.

Some earlier studies indeed concluded on significant net reductions in temperature-related mortality with global warming. Interestingly, the estimated mortality benefits from one of these studies were later integrated into major integrated assessment models (FUND and ENVISAGE), used inter alia to estimate the highly policy-relevant social costs of carbon. They were also taken up by Björn Lomborg and other authors, who have repeatedly accused mainstream climate science to be overly alarmist. Myself and others have pointed to the errors inherent in these studies, biasing the results towards finding strong net benefits of climate change. In this post, I would like to (i) present some background knowledge on the relationship between ambient temperature and mortality, and (ii) discuss the results of a recent study published in The Lancet Planetary Health (which I co-authored) in light of potential mortality benefits from climate change. This study, for the first time, comprehensively presented future projections of cold- and heat-related mortality for more than 400 cities in 23 countries under different scenarios of global warming.

Mortality risk increases as temperature moves out of an optimal range

Typically, epidemiological studies, based on daily time series, find a U- or J-shaped relationship between mean daily temperature and the relative risk of death. Outside of an optimal temperature range, the mortality risk increases, not only in temperate latitudes but also in the tropics and subtropics (Fig. 1).

Fig. 1 Exposure-response associations for daily mean temperature and the relative mortality risk (RR) in four selected cities. The lower part of each graph shows the local temperature distribution. The solid grey lines mark the ‘optimal temperature’, where the lowest mortality risk is observed. The depicted relationships take into account lagged effects over a period of up to 21 days. Source: Gasparrini et al. 2015, The Lancet.

Furthermore, the optimal temperature tends to be higher the warmer the local climate, providing evidence that humans are at least somewhat adapted to the prevailing climatic conditions. Thus, although ‘cold’ and ‘warm’ may correspond to different absolute temperatures across different locations, the straightforward conclusion from the exposure-response curves shown in Fig. 1 is that both low and high ambient temperatures represent a risk of premature death. But there are a few more aspects to consider.

Causal pathways between non-optimal temperature and death

Only a negligible proportion of the deaths typically considered in this type of studies are due to actual hypo- or hyperthermia. Most epidemiological studies on the subject consider counts of deaths for all causes or for all non-external causes (e.g., excluding accidents). The majority of deaths due to cold and heat are related to existing cardiovascular and respiratory diseases, which reach their acute stage due to prevailing weather conditions. An important causal mechanism seems to be the temperature-induced change in blood composition and blood viscosity. With regard to the cold effect, a weakening of the defense mechanisms in the airways and thus a higher susceptibility to infection has also been suggested.

Is the cold effect overestimated?

As in any correlative analysis there is always the risk of confounding, especially given the complex, indirect mechanisms underlying the relationship between non-optimal outside temperature and increased risk of death. Regarding the topic discussed here, the crucial question is whether the applied statistical models account sufficiently well for seasonal effects independent of temperature. For example, it is suspected that the lower amount of UV light in winter has a negative effect on human vitamin D production, favoring infectious diseases (including flu epidemics). There are also some studies that point to the important role of specific humidity, that, if neglected, may confound estimates of the effect of temperature on mortality rates.

Interestingly enough, there is still an ongoing scientific debate regarding this point. Specifically, it has been suggested that the cold effect on mortality risk is often overestimated because of insufficient control for season in the applied models. On the other hand, the disagreement on the magnitude of the cold effect might simply result from using different approaches for modeling the lagged association between temperature and mortality. In fact, the lag structures of the heat and cold effects are distinct. While hot days are reflected in the mortality statistics relatively immediately on the same and 1-2 consecutive days, the effect of cold is spread over a longer period of up to 2-3 weeks. Simpler methods (e.g., moving averages) compared to more sophisticated approaches for representing lagged effects (e.g., distributed lag models) have been shown to misrepresent the long-lagged association between cold and mortality risk.

Mortality projections

But what about the impact of global warming temperature-related mortality? Let’s take a look at the results of the study published in The Lancet Planetary Health, which links city-specific exposure-response functions (as shown in Fig. 1) with local temperature projections under various climate change scenarios.

Fig. 2 Relative change of cold- and heat-related excess mortality by region. Shown are relative changes per decade compared to 2010-2019 for three different climate change scenarios (RCP 2.6, RCP 4.5, RCP 8.5). The 95% confidence intervals shown for the net change take into account uncertainties in the underlying climate projections and in the exposure-response associations. It should be noted that results for single cities (> 400 cities in 23 countries) are here grouped by region. Source: Gasparrini et al. 2017. The Lancet Planetary Health

In all scenarios, we find a relative decrease in cold-related mortality and a relative increase in heat-related mortality as global mean temperature rises (Fig. 2). Yet, in most regions the net effect of these opposing trends is an increase in excess mortality, especially under unabated global warming (RCP 8.5). This is what would be expected from the exposure-response associations (Fig. 1), which generally show a much steeper increase in risk from heat than from cold. A relative decline in net excess mortality (with considerable uncertainty) is only observed for Northern Europe, East Asia, and Australia (and Central America for the more moderate scenarios RCP 2.6, and RCP 4.5).

So, contrary to the propositions of those who like to stress the potential benefits of global warming, a net reduction in mortality is the exception rather than the rule, when comparing estimates around the world. And one must not forget that there are important caveats associated with these results, which caution against jumping to firm conclusions.

Adaptation and demographic change

As mentioned already, we know that people’s vulnerability to non-optimal outdoor temperatures is highly variable and that people are adapted to their local climate. However, it remains poorly understood how fast this adaptation takes place and what factors (e.g., physiology, air conditioning, health care, urban infrastructure) are the main determinants. Therefore, the results shown (Fig. 2) rely on the counterfactual assumption that the exposure-response associations remain unchanged in the future, i.e., that no adaptation takes place. Furthermore, since older people are more vulnerable to non-optimal temperatures than younger people, the true evolution of temperature-related mortality will also be heavily dependent on demographic trends at each location, which were also neglected in this study.

Bottom line

I would like to conclude with the following thought: Let’s assume – albeit extremely unlikely – that the study discussed here does correctly predict the actual future changes of temperature-related excess mortality due to climate change, despite the mentioned caveats. Mostly rich countries in temperate latitudes would then indeed experience a decline in overall temperature-related mortality. On the other hand, the world would witness a dramatic increase in heat-related mortality rates in the most populous and often poorest parts of the globe. And the latter alone would be in my view a sufficient argument for ambitious mitigation – independently of the innumerous, well-researched climate risks beyond the health sector.

Addendum: Short-term displacement or significant life shortening?

To judge the societal importance of temperature-related mortality, a central question is whether the considered deaths are merely brought forward by a short amount of time or whether they correspond to a considerable life-shortening. If, for example, mostly elderly and sick people were affected by non-optimal temperatures, whose individual life expectancies are low, the observed mortality risks would translate into a comparatively low number of years of life lost. Importantly, short-term displacements of deaths (often termed ‘harvesting’ in the literature) are accounted for in the models presented here, as long as they occur within the lag period considered. Beyond these short-term effects, recent research investigating temperature mortality associations on an annual scale indicates that the mortality risks found in daily time-series analyses are in fact associated with a significant life shortening, exceeding at least 1 year. Only comparatively few studies so far have explicitly considered relationships between temperature and years of life lost, taking statistical life expectancies according to sex and age into account. One such studies found that, for Brisbane (Australia), the years of life lost – unlike the mortality rates – were not markedly seasonal, implying that in winter the mortality risks for the elderly were especially elevated. Accordingly, low temperatures in this study were associated with fewer years of life lost than high temperatures – but interestingly, only in men. Understanding how exactly the effects of cold and heat on mortality differ among men and women, and across different age groups, definitely merits further investigations.

200 Responses to “Will climate change bring benefits from reduced cold-related mortality? Insights from the latest epidemiological research”

  1. 1

    Thanks. This has long been a topic with contradictory claims, so it’s good to get a treatment that is careful and which tries to consider as much relevant information as possible, even if the conclusion is not particularly cheering.

  2. 2
    Al Bundy says:

    You can always put on more clothes, but folks tend to frown when you take too many off.

    Lots of places are approaching the point that outdoor activities will be dangerous for even young adults for weeks or months at a time. Of course, one can (if one is well off) hide indoors and crank up that carbon spewing AC, which will make things even hotter next decade. There’s a good chance that entire regions will have to be depopulated because they’re just too miserable and energy intensive to be worth inhabiting. Want peace in the Mideast? Just crank up the heat until nobody lives there anymore. (When crops bake to death on a regular basis, who’s going to bother planting? Ahh, just plant your corn in the winter. Low sunlight is better than cooked.)

    Maybe we’ll end up with reverse days – where people retreat to a highly insulated sleeping container during the day and come out at night. Hey, it worked for Dracula!

    Perhaps the difference in life-years lost between men and women is influenced by the fact that there aren’t too many female ditch diggers.

  3. 3
    NonScientist says:

    Let us address the last part. It’s well-known that heat causes few deaths in the general population outside of wilderness or occupational exposure, but it does cause some who are nearing death’s door to proceed through it. Here, that effect is discounted by considering only cases where life is shortened by about a year: “significant life shortening, exceeding at least 1 year.”
    In times past, one year was a good measure, but not now. With advanced medicine and 24/7 ambulance service with sophisticated life support on board, the end of life is often prolonged, and often unpleasantly. People who are at the end of natural life can have multiple near-death events and be dragged back into the twilight zone by modern technology.
    Heat deaths outside of work or being lost in the desert tend to happen during sleep. Going to bed on a hot night and passing peacefully in one’s sleep beats two more years of Alheimer’s or other formerly fatal conditions.

    I say this as someone with multiple health conditions and very poor heat tolerance. On beautiful summer day, I don’t got out for more than 15 minutes at a time or 25 min total per day unless I’ve calculated that effective temp is below a threshold, I have cooling vests and pay much extra to live somewhere with central AC. Back when I could, I’d go out for a run when it was 36C; sweat is one of Nature’s great inventions. No more.

    You know how much difference 30 C vs 32C makes to me? ZERO, NOTHING. Either way I’ll be inside, or outside and timing my exposure.
    Care to know what does make a difference? Price of electricity. The ‘progressive’ local government has figured out how to make electricity here cost over double the national average. It’s about 25 cents US/kwh, with less than half of that being for the power itself. I use fans for most cooling, but I’ve found a little AC is absolutely necessary or I’m heat affected and need weeks to recover.

    Climate change has its own costs, expanded insect range, faster loss of soil moisture, changed weather pattern and so on. Mass death from heat is not one of them. Falling into that sort of hype would damage the real arguments about CC, and it also annoys us who are actually heat sensitive.

    — the preview seems to have added bold font to my comment. I can’t see how to remove it.

  4. 4
    Johnno says:

    Some senior citizens decline to use electric heating or cooling in extreme weather for fear of ‘bill shock’ when the utilities bill arrives. That’s a socioeconomic issue. Then there is the question of grid stability under extreme demand. On 7th January 2018 western Sydney hit 47.3C fortunately with not too much humidity and few electrical blackouts. I’m told air conditioning barely coped at maximum setting. Sydney’s electrical power mainly comes from burning fossil fuels, another feedback loop. However there was little reported increase in mortality. The usual suspects said it was the urban heat island and in any case 19th century thermometers recorded higher.

    As with bushfires the high survival rate may be due to smarter adaptation. Neighbours were told to check on each other, hydrate and temporarily relocate from older homes. OK people adapted which may be reflected in future mortality data. But heatwaves are an unpleasant experience perhaps likely most summers.

  5. 5
    Spike says:

    I note Africa isn’t mentioned and guess it wasn’t in the study. With megacities like Lagos and a growing population, plus its already extreme heat, I guess this is likely to make warming even more dangerous in terms of net global mortality outcome.

  6. 6
    nigelj says:

    NonScientist @3

    You seem to be trying somewhat desperately to downplay the problems of fatalities due to increasing temperatures. Apparently it is out of concerns about additional electricity costs, which is a reasonable concern at first glance. The trouble is this type of reasoning becomes an excuse to suggest its best to do nothing about climate change, while missing the point that climate change is alreadly causing a wide range of problems that start to add up insideously if we do nothing.

    Renewable electricity is one of the easiest things to do, and it need not cost significantly more,and in fact wind power is now one of the lowest cost forms of energy. Sounds like your utility is ripping you off for whatever reason.

    Remember its not just end of life people killed in their sleep by extreme heat.

    “You know how much difference 30 C vs 32C makes to me? ZERO, NOTHING. Either way I’ll be inside, or outside and timing my exposure.”

    It might not make much difference to you, but 2 degrees becomes a significant difference in countries that are already very hot like India, and especially in poor countries. And what if its more than 2 degrees?

    “Climate change has its own costs… Mass death from heat is not one of them. ”

    Actually it is one of the most worrying possibilities. Climate change has already made heatwaves more common. They will also become hotter and longer.

    The European heatwave of 2003 killed over 20,000 people, and it has been determined climate change was a factor in this heatwave. “In the first quantitative climate change attribution assessment, researchers found that human influence at least doubled the risk of a heatwave exceeding the threshold passed during the extreme European heat wave of 2003.[1] The study also finds that climate change made such an extreme heat event 4 times as likely.[1]”

    Add high humidity to higher temperatures and heatwaves and it becomes absolutely intolerable.

  7. 7
    Veronika says:

    Since AC was mentioned several times in the comments, here is a bit more information on AC as a modifier of the temperature-mortality relationship. There are a number of studies for the US showing that vulnerability to heat has indeed declined strongly over the 20th century. Most of this decline happened after 1960 and can largely be explained by the expansion of residential AC usage (e.g., Barreca et al. 2015). So it seems there is a large potential of mitigating at least part of the additional heat-related mortality projected for developing countries, where AC usage is currently limited.

    Yet there are two important caveats: First, the beneficial effect of AC does not seem to be ubiquitous. A very recent study analysing 4 decades of data in Japan (Chung et al. 2018) found decreasing heat-related mortality risk over time, but no significant relationship with AC prevalence unlike in the US. Second, as long as the energy systems remain largely fossil-fuel based it needs to be factored in, of course, that AC is a potential remedy to lower heat risks but at the same time a technology that speeds up climate change.

  8. 8
    JCH says:

    In the US states and territories, the two states with the highest life expectancy are Hawaii and Minnesota. During the wintertime they have this odd thing in common.

    Close followers with high life expectancy: simple rule, places with very cold winters.

    Puerto Rico was in 3rd place.

    Florida is 23rd and Virginia 26th, and it does not have this odd thing in common with Minnesota. They are the only states of the old Confederacy in the top 26. States with mild winters dominate the bottom 26.

    I think you need to figure out what it is that Minnesota and Hawaii have in common.

  9. 9
    MMM says:

    For US temperature impacts, is a good resource as well.

  10. 10
    tamino says:

    Thanks for identifying one of the biggest issues with such analysis: that the annual cycle of mortality isn’t necessarily related to the annual cycle of temperature. I drew a similar conclusion in this post.

    To those who minimize the impact of a few degrees on killer heat waves, I’d say that 70,000 dead in Europe 2003 and 55,000 dead in Russia 2010 shouldn’t be dismissed as “ZERO, NOTHING”.

  11. 11
    NonScientist says:

    “crank up that carbon spewing AC”

    If temps have risen by, say 2C over today, then lowering it by 2C via AC is all that’s necessary to more than erase the indoor effects of CC. More than, because a properly size AC setup dehumidifies as well as cools. AC is typically sized to pump out a difference of over 10C, and the power needed to maintain a difference increases exponentially with the delta.

    TL:DR Cutting your indoor temp just enough to account for CC over 20 years takes very little power. Cutting it 5 or 10C eats a bunch. Solution: Dig a deeper basement and hang out there during heat waves.

    @Johnno 47C! Ouch!
    Sounds like a place which would benefit from combined evap/gas cycle AC – the evaporator part is outside the living space and doesn’t humidify indoors, so you can supplement it with a swamp cooler.

  12. 12

    Non-scientist, #3–

    It’s well-known that heat causes few deaths in the general population outside of wilderness or occupational exposure, but it does cause some who are nearing death’s door to proceed through it.

    No, I can’t agree that that is the case. The guest article contradicts that perception at multiple points, only the first of which is this:

    On the other hand, excess mortality from heat may also be high, with, for example, up to 70,000 additional deaths attributed to the 2003 summer heat wave in Europe.

    Then there’s the regional analyses, and *then* we can get into all the supporting anecdotal evidence from recent history (some of which actually is more than that, having also been subjected to scholarly analysis), such as the Russian heatwave/wildfire outbreak of 2010 (~11,000 dead); the Chicago heat wave back in 1995 (~800 dead); or even the Indian heatwave of 2015 (2,500+ dead).

  13. 13
    Carrie says:

    I’m not buying it.

    2016 report
    Speaking to, Dr Loridan said heatwaves remained our biggest killer when it came to extreme weather events (such as cyclones or bushfires).

    “It’s not only the biggest killer, but actually kills more people than all the other events put together,” he said.

    “The 2009 heatwave that hit Victoria and South Australia killed 432 people, or two and a half times the number of people killed in the Black Saturday bushfires that followed.”

    2017 report

    2018 report

    European deaths by heatwave

    People die from heatwaves for weeks after the event actually happens.

    A decent paper on solutions to global warming would be far more productive than one that navel gazes and ends up minimizing or questioning the ACCURACY of Mortality Impacts from global warming and climate change.

    This article and discussion comments are a sick joke, right?

    “To judge the societal importance of temperature-related mortality,….” who gives a toss about such judgments?

    “Climate skeptics sometimes like to claim that ….. ” no one sincere or sane gives a toss about what climate skeptics like or claim.

    Numbers of Deaths by heatwaves supported by scientific models and algorithms and navel gazing is an irrelevancy of epic proportions to the main game. It’s a waste of time and resources.

    Global warming, energy policy, economic policy and agriculture and the environment is at a cross roads for immediate serious action. That’s the issue. The rest is BS.

  14. 14
    Mr. Know It All says:

    I seriously doubt the 70K claim of “additional” deaths. The reason it is unlikely is because during the period 1999 to 2009 in the USA an average of 658 people per year died from heat related causes. Over the 11 years 7,233 people died in the US – those are CDC stats. And that may not be unusual at all – that is, no “additional” deaths.

    I suspect Europe is more frugal when it comes to power consumption for cooling than we are, but this article claims over 100 times as many people died in Europe from heat than in the USA. I do not believe it.

    [Response: Here you can see typical mortality data, this is from the state of Baden-Württemberg in southern Germany. The mortality spike during the heat wave is clearly visible, and it is not difficult to calculate additional deaths from those data. Essentially zero air conditioning there – I grew up there. In all age groups above 45 years the mortality was significantly increased. The number of 70,000 comes from a peer-reviewed study: But of course, just by sitting on your couch and speculating, Mr. Know-It-All can easily come up with a better estimate… -Stefan]

  15. 15
    jgnfld says:


    Quote for kia to ponder: “The good thing about science is that it’s true whether or not you believe in it.”

    ― Neil deGrasse Tyson

  16. 16

    AC is great for beating the heat, no doubt, additional CO2 emissions excepted–if you have access to it.

    In India and pretty large chunks of Africa, to name just a couple of places where this is true, access to *electricity*, let alone AC, can be pretty spotty. In fact, the headline number that you hear is that about 1 in 5 people globally do not have reliable access to electric power. In a double whammy, those folks tend to be concentrated in tropical areas where people already live closest to the thermal limits.

    The figure is better in urban areas, but even so about 1 in 10 globally have poor access to electricity. So, taking Lagos as an example, there are probably well over 1 million people with no reliable power there, since the estimated population is on the order of 15 million. (The official census number is 8 million, but that is from 2006, and sez here that it’s known to be highly inadequate. Which suggests a good reason for why Lagos isn’t in the study that’s our topic here–if there isn’t even good population data, what chance that there’s accurate mortality data for heatwaves?)

    AGW is a ponzi scheme in which the rich steal from the poor, and the old steal from the young. That’s a reality not easy to change, but let’s at least remember that our poorer cousins exist.

  17. 17
    Mr. Know It All says:

    14 – Stefan

    The first link you provided had not mortality data.
    The second link to the “peer reviewed” article requires credentials, or you can pay to view it. Is it standard to require payment to see science papers? I thought we wanted transparency? Do scientists expect the public to pay to read about CC?

    Anyway – back to “additional” deaths. So far I have seen no evidence that “additional” deaths occurred due to a heat wave(s), much less 70K additional. Please provide evidence if you can. The very minimum acceptable evidence of “additional” deaths due to climate change should include at least the following:

    1) Number of deaths, by week for the hot weeks in question – probably June, July, August. This should be provide for at least 30 years – so start with 1988. (Less than 30 years is not climate FYI.) For each of those weeks, list the temperature in the location where the deaths occurred, high, low, and average for the week. Indicate how many died during the heat wave. For those who died of “heat related” causes, note how many were in their last days due to poor health, and would probably have died anyway. Note also any increase in deaths from various diseases that occurred at the same time. Of those who died, note how may had access to cooling.

    2) Adjust the number of deaths by the population. More people means more deaths, heat wave or not. If, when you had a population of 300 million, 10,000 died, and when you had a population of 400 million 13,333 died, you have NO additional heat deaths – the rate is the same.

    3) Adjust for number of immigrants who may have unusual (for Europe) diseases, poor health, less access to cooling, etc.

    When you get all that compiled, have it all proofread and checked, and publish it here so we can take a peek. There may have been 70K “additional” deaths in one year due to heat waves in Europe, but it isn’t likely and this article provides NO evidence for it.


    [Response: Heat excess deaths in the extreme summer of 2003 in Europe have been quantified in a large number of studies. Here are just a few examples of studies (published in open access journals ) for estimates in major cities in France: (, Spain ( , and Italy ( and across Europe ( All of these clearly show that the extreme heat in the summer of 2003 caused significant number of excess deaths in European cities – on the order of hundreds to thousands of additional deaths in each city.

    The problem with the comparison you are suggesting in your above comment is that you compare the cited European number for excess deaths in 2003 with the US number for deaths directly related to heat (i.e., people dying from heat stroke etc.). In fact, only a small portion of the excess deaths observed during heat waves are actually due to heat strokes. The largest part die from respiratory or cardiovascular conditions that reach their fatal stage due to high ambient temperatures. In the report you are citing above these largest part of heat-related mortality is neglected. So no wonder the US figures you are mentioning are by orders smaller. -Veronika]

    [Response: That first link does show a mortality time series if you open the box 1. The second link will provide you the abstract of the paper titled “Death toll exceeded 70,000 in Europe during the summer of 2003”. It is usually verey easy to get free access to a full paper by emailing the author and asking for a copy (the mail address is given under the link I provided). -Stefan]

  18. 18
    J4Zonian says:

    ”It’s well-known” oops. Usually, ’it is well-known’ things are not only not well known, they’re not true. NS offers no support. ”occupational exposure” in an increasingly hot world will be a major cause of death.

    Nonscientist insists on making this mistake a couple of times. A 2°C rise in temperature doesn’t mean every day is 2° hotter. It means some days are cooler, some the same, and a lot are hotter, some a lot hotter—like the ones that killed 70,000 people in Europe in 2003 and thousands elsewhere, and millions soon—especially those with a choice between ”occupational exposure” and poverty.

    nigelj and others point out or hint at some of this:
    Subsidies and externalities for fossil and fissile fuels are far higher than for clean safe renewable energy, but solar and wind are still the cheapest power in a growing number of places and still dropping—with battery storage and no subsidies (except for f&ffs). Stopping fossil subsidies and spending the money on energy for people who can’t afford it will help with a lot of what’s going on here—the higher mortality rate of poverty. Poor people also die and get sick more from fossil fuels, and from lack of medical care, especially in poor countries, which tend to be near the equator. Just one more reason equality is a major solution to climate catastrophe. One thing, btw, that HI and MN have in common is that they’re blue states, with relatively good safety nets, & less inequality.

    AC changes, see Drawdown, David Roberts, Brad Plumer et al on flattening the duck, electrifying, etc. Fortunately, AC needs mostly correspond with solar energy peak. A couple of hours of storage each day takes care of most of the rest.

    Temps will probably reach 170°F, a temperature at which, if you go outside, you die.

    de Grasse Tyson’s quote likely comes from Philip K. Dick,
    ”Reality is that which, when you stop believing in it, doesn’t go away.”

  19. 19
    Dan says:

    re 17. ” Do scientists expect the public to pay to read about CC? ”

    Thanks for proving you have no clue about how science is conducted. You do not understand the process, let alone peer-review. And you certainly have not read any of the sciene in the IPCC reports (not just the summaries). Thanks for making it clear that you have no clue. Seriously. You are just an anti-science denier, flaunting your ignorance like the other clueless one, V. Truly disingenuous and full or red herrings. You dismiss peer-reviewed articles and somehow think you know more than climate scientists and epidemiologists around the world. True arrogance and ignorance.

  20. 20
    Steven Sullivan says:

    “The first link you provided had not mortality data.

    “The second link to the “peer reviewed” article requires credentials, or you can pay to view it. Is it standard to require payment to see science papers? I thought we wanted transparency? Do scientists expect the public to pay to read about CC?”

    Um, no, but many publishers do. Up until rather recently a great many science journals have had paywalls. (It’s been *scientists* who have pushed back by starting free-access journals like the PLoS series) It’s not the government, it’s good old capitalism. And btw, from the naivete of your question, I can tell you’re utterly unfamiliar with scientific research as it is actually done, Mr. “Know It All”.

  21. 21
    Michael Sweet says:

    I remember many days in the Tropics when I looked to see which side of the street had more shade before walking a few blocks. It was difficult to walk in the sun because it was too hot. It is already too hot in many locations for a man to work hard outside all day. You need hours of rest in the middle of the day to recover. Even a 1C increase in temperature will reduce the amount of work a person can do and kill weak people. People who live in temperate areas do not realize how heat affects work outside because they have not experienced it. Many of the poor are subsistence farmers who live and work outside.

    I live in central Florida now and last week a friend said it had been cool so far this year. He had not had any five shirt days. He works outside and counts how many shirts he soaks with sweat each day. In summer every day now is a five shirt day. 2C more and it will be too hot to work all day.

    For those who say they can simply increase air conditioning, what will you do for food when the heat kills animals and damages crops? Even if people left for the hot months when they returned their animals would be dead.

    Mr KIA is too stupid to access peer reviewed data. When I clicked the first link I got a graph that clearly showed about 1000 people out of 12 million had died from the heat wave. Extrapolate over all Europe and 70,000 is reasonable.

  22. 22
    Bill Bedford says:

    The hottest year in the CET record was 1976, not 2003.

    Wikipedia says: “The 1976 heatwave is understood to have been the cause of 20% ‘excess deaths’ and there were significantly more hospital emergency admissions from 24 June to 8 July 1976 than for the same period in 1975 or 1974. This compares to 59% excess deaths for the 2003 heatwave.”

    It is clear that even if the stated excess death figures are not entirely accurate, the possible tripling of the excess death rate between the years make it clear that societal changes in the period between the two years had more impact than the actual temperature.

    [Response: Which study says that 1976 was warmer? According to Barriopedro et al. (Science 2011) the hottest summers in Europe since 1500 AD were in that order: 2010, 2003, 2002, 2006, 2007. -Stefan]

  23. 23
    jb says:

    Regarding Knucklehead in America at 17.

    Mr. Knucklehead on the one hand wants to have free access to all academic papers and on the other hand he worships the recent ascendancy of so-called “free markets.” He can’t have it both ways. Paywalls are a function of the “free-market” seeping into the education and research communities. They are controlled by publishing companies, not the scientific community. Everybody hates them, but we have to live with them, at least until academics are able to take back control of their work product.

    That said, the existence of paywalls does not obviate the requirement that you need to be at least minimally informed in order to have an opinion (revolutionary idea, eh?). So Mr. Knucklehead needs to get into his Humvee, drive to the nearest college library and look at the necessary papers. Then, have an opinion. (Alternatively, he can ride his bicycle and then he can gloat about how he does more to reduce CO2 emissions than scientists who drive to work.)

  24. 24
    John Pollack says:

    Mr. KIA @14 I’m not sure what relevance official CDC statistics for the U.S. have to do with excess heat deaths in a notorious European heat wave.

    However, since you cite the CDC, I invite you to visit Nebraska this weekend. Grab a chair, skip the cold drink, and sit on the sunny side of the street all day. I should warn you that forecast high temperatures will be running around 37C, (98F) a mere 9C above normal. If somebody spots your body lying by the chair on the hot sidewalk, with foam coming out of your mouth, you can rest assured that you demise would go down in the official statistics – but NOT as a weather related heat death. The state medical examiner might find the cause to be “dehydration” , “heart failure” or perhaps “circulatory failure.” The CDC will be none the wiser. You see, in Nebraska, neither summer heat nor winter cold are officially acknowledged as a cause of death, de facto. The only kind of weather that officially kills people around here is thunderstorm-related. If you get struck by lightning, beaned by a 12 cm hailstone, crushed by a falling tree in a windstorm, or wrapped around a tree stump by a tornado, this will go down as weather related. Since no thunderstorms are expected this weekend, you’re totally safe.

    That’s why I appreciate the epidemiological/statistical approach to excess deaths over the official statistics approach for extremes of heat and cold.

  25. 25

    BB, #21–

    Hadley maintains CET these days, and you can find the webpage for that data right here:

    I note the presence of an interesting summary under “Other Information” on that page:

    “2006 was the warmest year on record for min HadCET. 2014 was the warmest year on record for mean HadCET. 2003 was the warmest year on record for max HadCET.”

    So, no, 1976 wasn’t the warmest year in the CET record; 2003 was. How ’bout that?

    And while I’m pointing out the obvious, let me add that, were there some other CET we decided to privilege over the official one, and were it to have 1976 as the warmest year, the record in Central England could still not be assumed to have the same profile as the pan-European record. Apples and oranges, don’t you know?

  26. 26
    Tegiri Nenashi says:

    “Some senior citizens decline to use electric heating or cooling in extreme weather for fear of ‘bill shock’ when the utilities bill arrives. ”

    And what is your solution, to make electricity more expensive?

  27. 27
    Johnno says:

    A point overlooked about aircon as a response to heatwaves is that it can double electricity demand. For example South Australia typically consumes 1200-1500 MW in mild weather but that goes to 3100 MW when temps get to 45C. Batteries charged by clean energy are a long way from supplying that extra power for hours or days at a stretch. That power will most likely come from gas fired peaking plant, perhaps fuelled by expensive imported LNG in countries that have depleted gas reserves.

    Evaporative air conditioning by swamp coolers gets less effective with rising humidity. As wet bulb temperatures approach 38C we are told some forms of work will be impossible without compressive heat pump AC. Humid heatwaves present a double layer of fragility for both humans and their support machines. If this is a concern try toughing out the next heatwave without AC.

  28. 28
    Al Bundy says:

    I have a couple of sayings:
    “I hate (Mr) know it alls. They make it ever so hard for those of us who do.”


    “I may not know much but I can figure anything out.”

    Kevin, what makes you think KillingInAction isn’t laser focused on those poor (colored) cousins? Their deaths are reason to celebrate.

    And yes, it’s hard to wrap one’s mind around the fact that a single degree will spike temps drastically on occasion. Seriously, universe, BE FAIR and make one degree one degree. Man, the universe is totally stupid. For proof, just ask a know it all.

  29. 29
    Al Bundy says:

    John Pollack,
    My best friend in college was a Pollack with Tay Sachs who lived long after his expiration date (he won a Mr mosquito legs contest by a landslide)

    I’m in Omaha. If you’d like, give me a shout. 402 913 6998

  30. 30
    Matthew R Marler says:

    Veronika Huber: Good essay. Thank you.

    Mostly rich countries in temperate latitudes would then indeed experience a decline in overall temperature-related mortality. On the other hand, the world would witness a dramatic increase in heat-related mortality rates in the most populous and often poorest parts of the globe. And the latter alone would be in my view a sufficient argument for ambitious mitigation – independently of the innumerous, well-researched climate risks beyond the health sector.

    Where would $2Trillion (for example) be better spent?

  31. 31
    Marco says:

    Bill Bedford refers us to the CET, also known as the Central England Temperature. Its relevance to a *European* heatwave appears somewhat peripheral.

    Bill Bedford also states that 1976 was warmer than 2003. Unfortunately, he forgot to mention that he meant the JJA temperature. Annually, 1976 was lower than 2003 (and quite a few other years).

  32. 32
    Mr. Know It All says:

    17 – Stefan and Veronika

    Thank you very much for the sincere comments. Since it took 2 of you to answer me, do I get a prize? :)

    Unfortunately, CDC stats acknowledge that most of the US heat-related deaths have as underlying causes:

    Cardio Vascular Disease – 56.6%
    External Causes – 28.7%
    Respiratory Diseases – 3.1%
    Diabetes, etc. – 3.2%
    Mental issues – 2.4%
    Digestive Diseases – 1.8%
    Other Diseases – 4.2%

    Therefore the claim that the CDC includes only direct-heat causes such as heat strokes is not correct.


    From this article cited by one of you:

    we find this excerpt:

    “During summer 2003, Europe experienced one of the worst heat wave events in recent history [8], with an estimated excess mortality varying between 25.000 and 70.000 deaths in Western Europe [9, 10]. The comparison of the impact of the 2003 heat wave between countries is hampered by the substantial differences in the methodologies employed to define heat wave events and to estimate the excess mortality [4, 6, 11, 12, 13].”

    So, was it closer to 25K or 70K? Quite a range.

    Bottom line: if you believe this, and if you believe it will continue or get worse, and if you believe it is a big problem, I suggest powering up for Air Conditioning in Europe. Nukes don’t put out a lot of CO2 – I’d look into those – maybe enlist Bill Gates – he used to be pushing some kind of nuke power – see what he knows.

  33. 33

    Marco, #31–

    Marco, thanks for accounting for BB’s seemingly strange claim that 1976 was the warmest year in the CET; I was really baffled where that came from. But knowing that it is the JJA temperature makes some sense of the situation. After all, the ‘catastrophe’ (as it is termed in the excerpt below) occurred in mostly in August–it was a bit earlier in, for example, southern Italy–so the JJA temperature is a relevant measure. But it’s not a perfect one, as indicated by the bolded text below:

    The United Kingdom experienced a warm summer with temperatures well above average. However, Atlantic cyclones brought cool and wet weather for a short while at the end of July and beginning of August before the temperatures started to increase substantially from 3 August onwards. Several weather records were broken in the United Kingdom, including the UK’s highest recorded temperature 38.5 °C (101.3 °F) at Faversham in Kent on 10 August. Scotland also broke its highest temperature record with 32.9 °C (91.2 °F) recorded in Greycrook in the Scottish borders on 9 August. Around 2000 people died in the UK and as a result, the government released its Heat Health Watch system, issuing warnings if temperatures rise above 30c in the day and 15c at night.[27] According to the BBC, around 2,000 more people than usual may have died in the United Kingdom during the 2003 heatwave.

    The epicenter of mortality was in France, not the UK, as the map of the temperature anomaly dramatically suggests. Casualties in Spain, Portugal and Italy were also quite significant.

  34. 34

    KIA, #32–

    Uh, dude, did you read your own source for comprehension? Because you appear to be saying that it shows that the CDC commonly recognizes indirect heat mortality, while your source clearly says that that is *not* standard CDC practice.

    In fact, the whole point of the study seems to be to quantify the undercount resulting from failing to recognize the indirect mortality; they arrive at the conclusion that:

    The analysis revealed that including these [indirect] deaths increased the number of heat-related deaths by 54% and suggested that the number of heat-related deaths is underestimated.

    So, it appears to me–phrasing it in honor of the approaching World Cup tournament–that you just scored an ‘own goal.’

    Yes, as is common with estimates of things tough to measure, there is a range. Maybe Veronika can speak to this, or Stefan, but I’ve followed this a bit over the years, and it appears to me that the lower estimates are mostly earlier ones and that as people have dug away at the question, the numbers have tended to increase. So probably the true number, whatever it is, is closer to the upper figure.

  35. 35
    Timothy Havard says:

    Having lived in Dezful, Kuzistan, Iran, The Danikal Desert in Ethiopia and Lagos Nigeria and worked in Sokoto, Kaduna & Maidugari Nigeria I have noticed that there is little thought put in recent times to building materials and building orientation.
    Older building made of very thick mud walls with “wind towers” to act as evaporative coolers which limited access to direct sunlight were quite comfortable. Even in Concrete block building an evaporative cooler in the living area with an AC to sleep was also comfortable.

    The main danger was attempting to move too rapidly across a large temperature gradient in either direction. This can be painful and stressful.

    It would seem that the socio/health aspect has a great deal of elasticity if our combined knowledge of insulation, local building materials and locally generated power are applied. Careful use of the cooler mornings (just get out of bed) avoids heat stress and to a lesser degree also the evenings.

    The same material/insulation knowledge applied in the colder climates will also yield dividends. Here in Scotland I wear a throat warmer (a scarf) in winter – it does actually help and I have asthma. I am however reluctant to give up my wood burner;kiln dried naturally.

  36. 36
    Mal Adapted says:

    Tegiri Nenashi:

    “Some senior citizens decline to use electric heating or cooling in extreme weather for fear of ‘bill shock’ when the utilities bill arrives. ”

    And what is your solution, to make electricity more expensive?

    “Internalizing the marginal climate-change cost of fossil fuels” entails raising their price relative to carbon-neutral alternatives. Once price parity is achieved, the build-out of the carbon neutral economy might be expected to ensue, until average energy prices are equivalent to what they are now.

    Under Carbon Fee and Dividend with Border Adjustment Tariff, there is a net transfer of income downward, because while lower-income people spend a greater fraction of their annual income on energy than wealthier people do, the poor spend less per year in total on energy than the wealthy do. For more info see

  37. 37
    tamino says:

    Re: #22 (Bill Bedford)

    Although 1976 wasn’t the hottest year in the CET record (that was 2014), the summer in 1976 was one of the hottest. And, the 1976 heat wave was one of, if not the, hottest.

    So why was the death toll in England in 2003 greater than in 1976 (both were substantial, but 2003 was worse)? You assume “societal changes in the period between the two years” but provide zero evidence. That’s not what we call science.

    1976 brought not only one of the hottest summers in the CET data, it was also one of the driest. Yes, I have hard data to back that up (the hadCEP data, Central England Precipitation).

    I grew up in Florida, so I know well the saying, “It’s not the heat, it’s the humidity.” Of course it’s not all the humidity — but it’s easier to take 100°F heat in the dry Arizona desert than 90°F heat in muggy Florida, as long as you stay hydrated. Sweat can be a beautiful thing, but only if it can evaporate. I speak from experience.

    Your eagerness to dismiss the deaths of thousands is disturbing. Your willingness to assign a cause which has no evidence is embarrassing — to you. My opinion: it’s because your motive is not to understand, it’s to support a climate denier narrative.

  38. 38
    JCH says:

    Obviously it is a complex thing, but in general life expectancy increases as you move either north or south of the equator.

    So the bulge in winter death rates is likely higher in warmer climates than it is colder climates. Minnesota has a lower annual death rate than Iowa, which has a lower death rate than Missouri, which has a lower death rate than Arkansas, which has a lower death rate than Louisiana.

    Doesn’t this open up the possibility that warming could result in more winter deaths?

  39. 39
    Andy Miles says:

    The question, and therefore the answers, misses the point. Climate change is not just about getting warmer as if everything else stayed the same. There will be sea-level rises, and more extreme weather events which will disrupt agriculture, and therefore food supplies, in addition to floods, and hurricanes, which will cause civilisational collapse, mass-extinctions, and and mass-starvation.

  40. 40
    Carrie says:

    32 Mr. Know It All while I get you don’t trust anyone or are at least skeptical of data points being presented fwiw heatwaves happen all over the world have done for centuries. In modern times, say the late 19th century established governments with the assistance of health deps, doctors, ambulance services, and thermometers records etc etc have been recorded and keep in archives. really modern records and statistical analyis is far advanced on the 19th century when scribes with abacus’ were required to crunch such nimbers.

    so the above are well known facts … although your mileage may vary. So there’s thing since agw came along …. special (unlucky) number crunchers at hospitals and ambulance services and fire brigades admin get to crunch a years worth of numbers about events and activities down to an individual human person level about such things as dropped dead from heat stress in Mall etc. This numbers are cumulative using computers which can produce numerical and graphic comparisons with years gone by and population shifts and so on.

    This ionfo goes through so many different hands and organisations it;s impossible to defraud and checks and balances occur throughout. Now given the lack of competance in your country, well I cn accept you may default to reject anything coming out of there automatically, ala WMD useless military and so on …. corrupt politics and corporations and stock markets etc .. and that’s fine, but you really should consider accepting the output of quite intense accurate number crunching by the rest of the advanced world ….. all things being equal they know to expect X number of deaths due to summer heat at any particular place +/- 5% or so ….. so when the temps spike and humidity rockets and ambulance call outs go through the roof and all the hospital; beds are full and all the local funeral homes are full they do a calculation that accurate enough to determine how many NUMBERS were most likely caused the extreme heat wave (of snow storm or whatever)

    iow the EXCEPTION proves the Rule … LOGIC my dear friend. It doesn’t matter if the numbers are not perfect or the range is large or even if they LOSE a few years of data in a computer meltdown for some cities towns – the import is A) It gets Really F****** HOT = B) More people F******* DIE

    That’s basic logic. Got it?

    Is it getting really F******** HOT in places more so than normal? Shit yeah it is …. eg All over Europe and across Russia in 2003 is one example.

    It’s quite simple really so long as the records from the Coal Face are done and compiled correctly. Easy as ‘Pi’ actually – seriously think this through intelligently.

    Please stop checking if there really are the correct number of matches in the box you just bought while you house is burning down to the ground. Logic? Get it? :-)

  41. 41
    MPassey says:

    Nigelj @6: You state: “Renewable electricity is one of the easiest things to do, and it need not cost significantly more, and in fact wind power is now one of the lowest cost forms of energy. Sounds like your utility is ripping you off for whatever reason.”

    In a prior thread you referenced the Lazard cost of energy analysis, perhaps a source of your statement about the cost of wind power. But you have to be clear about what Lazard says:

    “Analysis excludes integration (e.g., grid and conventional generation investment to overcome system intermittency) costs for intermittent technologies.”

    Also: “Although alternative energy is increasingly cost-competitive and storage technology holds great promise, alternative energy systems alone will not be capable of meeting the base-load generation needs of a developed economy for the foreseeable future. “

    Integrating renewable electricity into a reliable grid is not one of the easiest things to do. Can you give any real-world examples of electrical systems where adding a significant amount of renewables has made the electricity cheaper?

  42. 42
    Hank Roberts says:

    Did “Bill Bedford” ever reply with a source for his claim?

    ‘oogled, can’t find any support for what he believes. Did he ever reply?

  43. 43

    M Passy, #41–

    Two things: #1–Change always costs. So rapid transformation of the electrical system away from dependence on fossil fuels, necessary though it is, will have costs, too. However, there are some cases now in which it has proven cheaper at the project level to build new wind than to maintain and operate existing coal capacity. For instance:

    In general, systems integration issues are real, but are also proving soluble.

    #2–A reference from 2013 is not going to be very useful today. The rate of change–and by change I mean “rapid decrease in renewable energy costs”–is too rapid.

  44. 44
    zebra says:

    @MPassey #41

    The moderators have been nice enough to set up a thread for discussing mitigation issues– Forced Responses. You just have to scroll down to older entries.

    I think the fact that commenters can’t be bothered to be courteous and considerate, even when there is so little effort involved, is cause for pessimism about humans cooperating to solve the climate problem.

    I will be happy to answer your questions on FR if you re-post on that thread.

  45. 45
    Marco says:

    Hank, *I* answered. He likely did not mean “hottest year”, but hottest summer (JJA). Still, it is the CET, so its relevance to the European heatwave is somewhat peripheral.

  46. 46

    Hank, #42–

    Did “Bill Bedford” ever reply with a source for his claim?

    No, at this point it looks as if his comment was a ‘drive by.’

    …can’t find any support for what he believes. Did he ever reply?

    No, but Marco helped out the cause of understanding by pointing out the kernel of truth in BB’s comment. As it turns out, 1976 was the hottest *summer* in the HADCET record, though not the hottest year (not even close). Given Marco’s hint, I was able to find the seasonal rankings here:

    There’s more, but turning to monthly data, Hadley also has that sorted.

    For those two measures the title is split between ’76 and ’95.

    As far as *yearly* rankings go, as mentioned above:

    2006 was the warmest year on record for min HadCET. 2014 was the warmest year on record for mean HadCET. 2003 was the warmest year on record for max HadCET.

    Bottom line on Bill: yes, the warmest JJA in CET was in fact 1976, and if you are picking categories to check, JJA is not the worst pick you could make. But there is a *ton* of variability in CET, compared with most familiar temperature data sets. I think that 1) meaningfully teasing out the relation between climate stats and the mortality record in England in 2003 would take more than just picking canned rankings from CET; and 2) CET is a fairly poor data set to look at in the first place if you are interesting in mortality in Europe, since the English toll was much lower than in many other places. The #1 place to look would be in the French record.

  47. 47
    Johnno says:

    @36 It’s interesting that the UK has a winter heating allowance for those born before 1953 and haven’t retired to Spain. Perhaps in future there will be an AC rebate for summer. Australia had the infamous ‘pink batts’ scandal in which free ceiling insulation was supposed to reduce utility bills. It appeared the thermal comfort effect was minor but several installers died of electrocution or heat stroke.

    @41 wind power typically goes missing in action in calm weather heatwaves when aircon use is highest. When it is both hot and windy we get fires. Increasingly it seems that temps linger on after dark say 30C at midnight. Realtime solar is not powering AC unless we have a large amount of energy storage. For this reason batteries are being installed in some public housing areas but that cost can’t be sustained.

  48. 48
    nigelj says:

    Carrie @40, Ha ha, very good. Nit picking on the exact numbers obscures the obvious and urgent risk. However I have observed that Mr KIA has a well polished ability to not get the point. It seems to be his purpose in life.

  49. 49
    nigelj says:

    M Passey @41, talking about cheaper power is a total strawman. Nobody is making a case that renewable electricity will be cheaper in the short term, however it may well be in the longer term. However the information we have is the economics are at least good right now, and this is why coal is already a dying industry in America.

    Estimates are that we need about 10% of baseload power. Baseload could be provided by renewables like hydro, geothermal or nuclear in many cases, or gas as a last resort.

    Details about renewable energy are getting “off topic” on this thread anyway. Its better on forced variations, if you have some point to make.

  50. 50
    Keith Woollard says:

    I can’t really sit back and listen to supposed scientists guessing at answer using nothing more than their logic. This is not a philosophy site!

    The obvious answer is to look at latitude vs life expectancy. Clearly there are many factors but all the studies I have found show the exact opposite of what JCH@38 has claimed once socio-economic factors are removed.

    And don’t forget 23 degrees either side of the equator HAS NO REAL WINTER. Some people might call it winter. How on earth can Hawaii’s winter be called cold!!!!! – again – JCH, @8

    But really the worst comes from the world’s greatest anonymous statistician@37. There is absolutely no modelling I have ever seen that suggests relative humidity will increase with climate change. Most models assume an increase in absolute humidity only. There is no real consensus on whether relative humidity will even stay constant, let alone rise. Climate change is not going to convert western desert climates to eastern humid sub-tropical!
    And for the record, my reading says 1976 was worse for England than 2003. Continental Europe was affected far more than England was in 2003. If you read the reports, even at the height of the 2003 English heat wave, the number of deaths per day were still lower than normal mid-winter rates.