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Global Warming Causing Heat Fatalities

Posted on 24 April 2012 by dana1981

One of the fallback positions of climate denial after the assertions that "It's not happening" and "It's not us" fail is "It's not bad."  The latest incarnation of this myth courtesy of Pat Michaels' serial data deletion colleague Chip Knappenberger argues that those who seek to mitigate global warming are actually endangering public health because, and believe it or not this is a direct quote:

"“longer, more intense and more frequent heat waves” may actually improve the public health and welfare"

Here is the specific argument Knappenberger makes in attempting to defend this seemingly absurd thesis:

"more frequent exposure to heat waves will lead the population to adapt to them, better preparing them for their occurrence, and ultimately reducing the rate of mortality and morbidity."

By this logic gang violence is great because it makes people more adept at dodging bullets. 

Knappenberger cites a paper he co-authored, Davis et al. (2003), which found that heat-related deaths are less common in hotter cities.  This makes sense, as hotter cities have the infrastructure (i.e. air conditioning units) to cope with hotter temperatures.  They do not have to adapt - they are already adapted to the heat, whereas most heat-related deaths come in regions which experience uncommon heat events (but are now experiencing them more and more frequently due to global warming).  Thus this point does not support Knappenberger's argument that more heat waves would be beneficial.

Knappenberger describes the second point in Davis et al. as follows.

"over time, the rates of heat related mortality across virtually all the cities that we studied were declining even in the face of rising summer temperatures"

This point, however, is contradicted by more recent research.

Zanobetti et al. on Short-Term Heat Impacts

Zanobetti et al. (2012) take an interesting approach in investigating the relationship between hot weather events and mortalities.  Since the age group most at risk for heat deaths are the elderly (those over 65 years of age) with predisposed illnesses, Zanobetti compared Medicare data from 1985 to 2006 from 135 U.S. cities to summer temperatures.  The authors explain the reasoning behind their approach:

"By restricting the analysis to within a city, we avoid all confounding by factors that can vary across a city or region. By looking only at year-to-year variations around the city-specific trend in exposure, we eliminate potential confounding by trends in other exposures, such as smoking, and focus on whether essentially random meteorological events are related to health."

Zanobetti et al. find that larger summer temperature variability leads to more deaths among the elderly.  Each 1°C increase in summer temperature variability increased the death rate for elderly with chronic conditions between 2.8% and 4.0%, depending on the condition (emphasis added):

"A 1°C increase in temperature SD [standard deviation] is a plausible increase in some regions. Based on our findings, this increase in temperature SD would increase all-cause mortality in our MI [myocardial infarction] cohort by 5%, for example. Based on an average of 270,000 deaths per year across all four cohorts, a 5% increase in mortality would correspond to 14,000 additional deaths per year due to an increase in temperature variability in the United States."

Sherwood and Huber on Long-Term Heat Impacts

A 2009 paper by Sherwood and Huber examines a worst case scenario in which the average global surface temperature warms in the ballpark of 10°C a few centuries in the future.  They note that a wet-bulb temperature (Tw) exceedence of 35°C for extended periods should induce hyperthermia in humans and other mammals, as they become unable to sufficiently dissipate heat.  In short, if Tw(max) of a particular region were to exceed 35°C for long periods of time, that region would effectively become uninhabitable to mammals.

"A 4°C increase in Tw would then subject over half the world’s population annually to unprecedented values and cut the “safety buffer” that now exists between the highest Tw(max) and 35°C to roughly a quarter. A shift of 5°C would allow Tw(max) to exceed 35°C in some locations, and a shift of 8.5°C would bring the most-common value to 35°C."

Based on their climate model simulations, Sherwood and Huber found that Tw increases somewhat more slowly than the average global surface temperature, such that a 1°C average global warming corresponds to a 0.75 to 1°C Tw increase.  Therefore, an 8.5°C Tw increase would require approximately 11°C global warming.

"We conclude that a global-mean warming of roughly 7°C would create small zones where metabolic heat dissipation would for the first time become impossible, calling into question their suitability for human habitation. A warming of 11–12°C would expand these zones to encompass most of today’s human population."

"A global-mean warming of only 3–4°C would in some locations halve the margin of safety (difference between Tw(max) and 35°C) that now leaves room for additional burdens or limitations to cooling."

"If warmings of 10°C were really to occur in next three centuries, the area of land likely rendered uninhabitable by heat stress would dwarf that affected by rising sea level."

In short, Sherwood and Huber find that there is a limit to what humans and other mammals can adapt to in terms of rising temperatures.  It will likely take a few centuries for global temperatures to reach that limit, but eventually large regions of the planet could become effectively uninhabitable, beyond what mammals can adapt to.

McInerney & Wing (2011) also examined the Paleocene-Eocene Thermal Maximum (PETM); a period about 56 million years ago during which global temperatures increased 5 to 8°C over a period of about 200,000 years.  They found that most species were able to avoid extinction by adapting to the increasing temperatures, for example by becoming smaller (increasing their surface area to volume ratio and thereby being better able to shed bodyheat).  Secord et al. (2012) similarly concluded that many species became smaller during the PETM and grew larger after the PETM (Figure 1).

Secord Fig 1

Figure 1: Summary of percent mean body size change in genera that exhibit change from the latest Paleocene to the PETM (left), and from the PETM to the post-PETM (right). No genus exhibits a size increase in the PETM or a decrease after the PETM. Compiled from published sources, except for Sifrhippus from this study. Asterisks indicate genera that first appear in the PETM (Secord et al. 2012).

Our problem is that current climate change is occurring much faster, over just centuries rather than the millennia of the PETM, and thus species will not have sufficient time to evolve in this manner.

Warmer is Not Better

The Knappenberger argument that higher temperatures will decrease heat-related deaths and thus benefit humanity thus suffers from two major flaws.  The first is that while fewer heat-related deaths occur when humans are adapted to high local temperatures, heat-related deaths will nevertheless rise in unprepared regions until they become adapted to those rising temperatures (i.e. by installing the necessary cooling infrastructure).  Zanobetti et al. illustrate that increasing heat-related deaths is already a reality.

The argument also neglects the long-term limit - there is a point at which temperatures can become too hot for humans and other mammals to survive.  If we continue on a business-as-usual path as Knappenberger promotes, we will likely reach that point within a few centuries, and the costs of losing the habitability of large regions of the planet are incalculable.

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Comments 51 to 76 out of 76:

  1. michael sweet (#46): My original article that dana1981 wrote this thread in response to was regarding the EPA’s failure to consider adaptation when assessing whether greenhouse gas emissions were endangering the public health and welfare in regards to extreme weather events—I used heat-related mortality trends as an example of why I think the EPA was wrong. So, my primary focus is on the U.S. I am not sure what qualifies as a “poor” country, but here is a (non-peer reviewed) study out of India that shows that very simple adaptive measures (i.e., public awareness campaigns) seem to result in lowered heat-related mortality. I imagine that they could do so in the future as well. MMM (#47): I understand that the your two statements are not contradictory. I don’t think that your #2 is a given—that is my whole point! Composer99 (#50): My link was supposed to be back to my upthread comment #12. Martin Lack (#51): I am not an economist. -Chip
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  2. Chip Knappenberger - Most of your links have been inoperative; you might want to review the Comments Policy notes on link insertion. I would have to agree with MMM's post - you claim the Jacobson conclusions are pre-determined without actually providing any issues with the causal chain between CO2, pollution, temperatures, and mortality. Secondly, as MMM pointed out, effects on mortality due to adaptations are a different question than whether AGW will produce higher mortalities than would occur otherwise. You are trying to change the question, and numerous posters have (quite correctly, IMO) called you on it.
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  3. KR (#53) and Moderator (#45), Of course I am not considering what would happen in the absence of adaptation…as my original Master Resource article points out, that is precisely what the EPA did, and such a consideration is completely unrealistic. People don’t want to die, so they adapt as best they can. And sometimes, as I believe to be the case with heat-related mortality, the adaptations make you better off than you were before. -Chip
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  4. Chip, I think you're still having some logic problems.
    My original article that dana1981 wrote this thread in response to was regarding the EPA’s failure to consider adaptation when assessing whether greenhouse gas emissions were endangering the public health and welfare in regards to extreme weather events"
    If people need to adapt to a threat like increased heat waves, then they endanger public health and welfare. This gets back to my gang violence example. People can adapt to gang violence by staying indoors more, for example, but the fact that they can adapt to the threat doesn't mean the threat doesn't exist. Adaptation also has a cost, as we've noted repeatedly. I do agree that adaption will likely continue. However, you still have these two logical problems. 1) You haven't shown that people are adapting because of the increase in heat events. That's an assumption, and thus you have not demonstrated that the EPA is wrong to classify AGW as a heat-related threat to public health and welfare. 2) Even if people are adapting as a direct result of increased heat waves, that also doesn't undermine the EPA conclusion, because they are adapting to the threat. Your argument is that we're better off adapting to the threat than if the threat didn't exist. That may or not be true, but even if it's true, the EPA is correct to call this a threat. It just happens to be a threat that we can successfully adapt to, up to a certain point, at a certain cost.
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  5. Chip Knappenberger:
    Composer99 (#50): My link was supposed to be back to my upthread comment #12.
    Thanks, I believe a mod fixed the link.
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  6. Chip #54 More nonsense. The EPA has pages and pages on local adaption strategies. It's almost as if Chip is suggesting that because he wrongly believes the EPA is making decisions without considering other strategies (adaption) then any other strategy (mitigation) is wrong. - the adaptations make you better off than you were before. - So what? What does that have to do with mitigation and the EPA? Your original article says that we should let heat waves happen and then people will adapt. You are saying that in preventing disaster, we are causing more disaster. You've yet to show any logic, science, statistics, or anything else (besides the twisted logic about people learning their lesson and letting poor people unnecessarily suffer) that actually supports your point. And even if you did, your theory is highly unethical. Read what you wrote: -- “longer, more intense and more frequent heat waves” may actually improve the public health and welfare, and that in trying to prevent them, the EPA is causing harm. -- How about adapting beforehand. Then mitigate for the next few generations. How is that possibly harmful? Not enough people dying to get them to adapt? You are being so ridiculous.
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  7. muoncounter you are pointing to 138 deaths from heat versus 76 from cold (2010) but the statistics from 2006 show 60k more deaths in DJF than in JJA. There can be explanations that are not strictly weather-related like the seasonal spread of flu, but I don't think that explains the whole difference.
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  8. dana1981 (#55), Thanks for the hosting the discussion. I don’t think we’re really that far apart on this particular topic, but obviously, if we were in complete agreement, you wouldn’t have written your piece in the first place. :^) I agree that adaptation to extreme heat (a threat) is ongoing (even without climate change). I just think that climate change hastens the adoption of adaptive measures. And thus more quickly induces us to reach a point where we are better off than we were before. Heat can kill if you aren’t prepared. This is true today, in the past, and in the future. We could try to force the climate to a state where there are no heat waves and thus potentially solve the whole problem. Or, we could try to force the climate to a state the same as today’s (or the 1950s, or whenever) when heat waves presumably occur less frequently (and with less intensity) than they will in the future. It is not clear to me , although admittedly it seems clear to most everyone else on this thread, that this solution produces less heat-related mortality than will occur under, say, midrange scenarios of unmitigated climate change. You just can’t say that since heat waves are a threat, that more of them are a bigger threat. Most any type of weather is a threat of some sort. That’s why “shelter” is a basic need. But once you have sufficient shelter, then the threat is reduced. Right now, many places don’t have sufficient shelter from heat-waves which occur in the course of a normal climate. Global warming may hasten a solution to that problem. It seems to me, that an assessment of the impacts on public health and welfare should at least consider such a possibility and that short-term negative impacts may be replaced by positive ones in the long-term, once sufficient shelter has been established. -Chip PS. And grypo (#57), I am somewhat familiar with the EPA’s adaptation strategies when it comes to extreme heat events, in fact, I had a hand in the development of their Excessive Heat Events Guidebook. But none of that matters when it comes to how the EPA assessed endangerment from GHG emissions. This is what they have to say about adaptation: "EPA considers adaptation and mitigation to be potential responses to endangerment, and as such has determined that they are outside the scope of the endangerment analysis."
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  9. Well Chip, to return to my analogy, your argument is akin to saying we should require everyone to buy bulletproof vests instead of taking measures to reduce gun violence. Your approach doesn't address the existing threat, it simply forces people to adapt to it (at a significant cost). The problem is that you're arguing the threat doesn't exist, when you should be arguing that there are different ways to address the threat. I agree with that. I believe it was Lonnie Thompson who said that climate change will result in some combination of mitigation, adaption, and suffering. But your fundamental argument, that the EPA is wrong to call increased AGW-caused heat events a threat, is incorrect.
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  10. Who cares if the endangerment finding looked at the question of what it would be like if no adaption or no mitigation occurred? That's a different argument and question. You are avoiding the argument being presented here. You've yet to show how mitigation is harmful. Your reasoning doesn't address ethical concerns. Your evidence doesn't back your claims.
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  11. dana1981 (#60); You have made the point on several occasions that adaptation to heat waves is occurring without consideration of a changing climate. So, a certain value of your “significant cost” of on-going adaptation is unrelated to climate change. I hypothesize that climate change may hasten the adaptation saving more lives sooner. Does it add costs beyond those that were going to be spent anyway? Like I said, I am not an economist. But doesn’t the possibility exist that money spent now is cheaper than money spent later? I don’t know the answers, but I think it is a possibility worth considering and not one summarily dismissed. One way to reduce the threat of wolves on sheep is to kill all the wolves, another is to train a sheep dog to keep the wolves at bay. -Chip
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  12. 62, Chip, You have a rather simplistic view of things. Clearly if things get hotter (1) climate control equipment must run longer, more frequently, and at higher power, (2) there will be areas that would not have needed anything before but do now and (3) there will be more extreme events, even for prepared areas, that exceed or strain capacity (or require the expense of much greater capacity simply to prepare for such peaks). We're not talking about costs "that were going to be spent anyway." We're talking about adding (substantially) to those costs. That is fairly obvious for anyone to see. Or did I misunderstand your statement?
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  13. Eric#58: Are you equating deaths that occur in a particular calendar month with deaths due to a specific set of causes? Clearly there were more deaths in the US during each of the years given in the NWS chart/table - but my father's death this past February, for example, was not due to cold weather. He was 95.
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  14. Chip Knappenberger - Climate change is just that: change. And changes, even if successfully adapted to, always cost money for those adaptations. Monies that would not have to be spent otherwise - new costs...
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  15. Here's another data point: Texas temperature-related mortality, 2003-2008: -- sourced above Texas is 'highly adapted' to heat, however, the figures in this period - which, of course does not include the record-shattering heat wave of 2011 - show that more people still die of heat-related causes on an annual basis. This argument that "heat-related deaths are less common in hotter cities" is totally bizarre and suggests a very jaundiced worldview.
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  16. Muoncounter, I am sorry to hear of your father's death. I don't know why there are 60k more deaths in the U.S. in winter than there are in summer. I would appreciate any references anyone has to help explain it. In the absence of such references I have to assume that cold weather is a factor in some of those deaths even indirectly. For example more people confined indoors with less ventilation than summer.
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  17. It's such a simple question that I asked above, that I was sure there was a simple answer. But while there are some simple answers, e.g. they are incomplete.
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  18. Eric#67: Thanks for your kind words. Here's another take on the 'more people die in winter, but not necessarily due to extreme cold' story. Most of them are due to strokes and heart attacks. "This is because the blood becomes more liable to clot in people who are exposed to the cold." ... Studies show elderly people, and particularly those on low incomes, are at the greatest risk. There are a number of reasons why. Those that succumb are not necessarily sick already, but older people's blood vessels tend to have rougher linings than those of younger people, which makes them even more susceptible to clotting. We know that there will still be winter even under the worst global warming scenarios, so this cause of death may not vary all that much. Indeed, it may rise as the population ages. However, when the hot get hotter, heat-related deaths will rise. Unless, of course, we do as Chip suggests and simply 'adapt.' We can simply evolve so that we are born wearing one of these.
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  19. Re some posts above: seasonal flu deaths can run pretty high (3k to 49k per season). adaptation: there's a mess of inexpensive adaptations to heat waves, but we have known that we need them for decades (we've had heat waves before, and they've killed before), and there's no evidence that we are getting smarter or learning any faster than in the past. It's likely that people pay more attention for a few years following a bad heat wave; it would not be surprising to see some reduction in the deaths-per-degree rate afterwards. Cheap adaptations range from color of automobiles (some of those heat-related deaths are kids left in a car in the sun -- we make mistakes, sometimes horrible ones) to siting and shading of houses (and zoning and homeowner's association codes) to learned-but-unconscious reactions to heat (living in CA, over the years got to see about a half-dozen Gulf Coast friends-and-family get slightly dehydrated because they did not notice they were sweating). A sudden heat wave in a normally cool place will catch people without full physiological adaptation (takes a week or two), and without having already learned heat-friendly habits (e.g., hydration cues), so some adaptations are just not available. But most adaptations entail a minor expense/inconvenience, else we would have made them already. About the only one that does not is albedo change (white cars, white roofs, white pavement, white clothing) -- and notice that generally we don't do that yet, either.
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  20. The best "adaptation" we've made in Adelaide after our disastrous record-breaking heatwave 4 years ago is organisational and behavioural. The Red Cross has a list of people who've signed up to be contacted for all kinds of problems. When heatwave conditions are predicted, they get on the phones and start nagging people to drink water and remove their shoes to cool off. (Elderly men are notorious for maintaining "decent" dress - singlet, shirt, tie, jacket, trousers, wool socks, lace-up leather shoes - and sticking to routines like a cup of tea at 10.30am rather than frequent drinks of plain water.) Radio and TV stations also broadcast messages, not for people at risk, but for families and neighbours to get on the phone or visit to make sure that old or sick people are drinking enough and actually using their fans and air conditioners rather than trying to economise in their usual way. And changing the colour of cars won't save kids trapped in hotboxes. The temperature difference is measurable but nowhere near enough to be survivable for a child or an animal left there for more than a matter of minutes when the outside temperature is over 35 or 40C. The car temperature rockets to 50+ in a virtual blink of an eye. "Full physiological adaptation" is a nonsensical concept for a fortnight or more over 35C when some of those days also exceed 40C. I've lived through it. By the time you're at 6, 8 or 10 days of this stuff, you might have better water drinking habits, but you're exhausted. And so is everyone around you. Tired people make mistakes - and they can't sleep properly either. If they're susceptible to illness, they become more susceptible.
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  21. To address that some posters may seem to be confusing thermometer temperatures with wet bulb temperatures (my apologies if I read them wrongly): This is not about heat killing people and animals that need evaporative cooling to survive, but a combination of heat and humidity killing people and animals that need evaporative cooling to survive - this is not about the heat, but about the heat index, a measure of heat and humidity. Over the very long run, with the atmosphere containing more and more water as the planet accumulates more and more heat energy, it may be harder and harder for the thermometer temperature to go up and up. But we will see at the same time the heat index - the wet bulb temperature - continuing to go up and up. This simply reflects the facts of what we see: For instance, in the US, in humid environments like Florida we see high thermometer temperatures being almost always no higher in the summer than in the 95 degree F range, but in the dry climates in the southwestern US the thermometer temperatures can reach well over 110 degrees F. Yet the heat indexes - a measure of heat and humidity - can be the same, overwhelmingly uncomfortable if not yet high enough to be deadly to everyone. The online heat index calculator I linked to at #11 shows that even with just thermometer temperatures of 100 and 105 degrees F, which are thermometer temperatures that humans and animals experience today and survive just fine, we would see heat indexes of 150 and 176 degrees F respectively with just a relative humidity of 75%, deadly to humans and some animals even just within hours. The wet bulb temperature that would be deadly within hours to all humans and some animals talked about in the article is 35 degrees C and 95 degrees F, a heat index of 170 to 196 degrees F according to Huber. Side note to address that some seem to think that all will be well no matter what: I don't think that civilization can survive no one being able to go outside without being killed in just hours, but that's just me. But even if with super high technology in some science fiction future in a few hundred years global civilization could barely handle with extreme stress billions of people in the equatorial regions living in such summertime death zones, what about the wild animals? Whole continents in the middle parts of the planet would become dead zones, essentially devoid of all wildlife - killing off essentially all birds and mammals in these areas would disrupt the food chain so much that the whole ecosystem in these regions would collapse entirely. This impending mass extinction on so much of wildlife including on the pinnacle of evolution, the mammals, does not bother the fake skeptics? They talk as if they care only about humans. For clarity, to avoid confusion, what we need are not just graphs covering the last 50 years that show the global thermometer temperature increase, but graphs that show the global wet bulb temperature increase - graphs that show the global heat index increase. I'd bet that given that water vapor has increased by 4% over just the last 40 years, these global wet bulb temperature or global heat index graphs would uncover trends that we otherwise could not see. (And I think that it would be a good idea to break down the global data on the heat index to include comparisons of trends in heat indexes with respect to nighttime vs. daytime, summer vs. winter, and arctic vs. the equator. We should all know that globally, nighttime temps rising faster than daytime temps, summer temps rising faster than winter temps, and arctic temps rising faster than equatorial temps have been happening and are possible only with a significant increase in greenhouse gas activity.)
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  22. Thanks to adaptation our grandchildren will have to live inside in a fully air conditioned city? What a wonderfull world!
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  23. While perhaps not a totally analogous, this discussion reminded me of a documentary I saw recently on the hunter gatherer method of 'persistence hunting' where hunters would chase prey who could run much faster than the hunters could. The narrator explained that the hunters could catch their prey because the speed that the animals were running at prevented the prey from panting, their only method of reducing body heat. The last scene showed an antelope, standing, unable to move because of heat stress, while the hunter walked up and killed it with a spear. High "Wet bulb" temperatures seem to have the same effect for people, inhibiting or preventing the cooling produced by the evaporation of sweat.
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  24. Chip @62 uses an analogy of wolves killing sheep, and argues for protecting the sheep. A better analogy to global warming is a case where your neighbour is breeding wolves, and it's his wolves that are killing your sheep, not the one's nature left running around in the woods. It would appear that Chip thinks having the neighbour breeding wolves is good for your sheep farm, because it will force you to adapt and improve your defences against all wolves, including the small number that existed naturally. Why Chip doesn't think that stopping your neighbour from breeding wolves is a good idea, I can't say, but that's the analogy to his position on heat stress.
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  25. Chip (#51) says, "I am not an economist". I think I knew that. Neither am I but, unlike you, I do not second-guess genuine experts in any field. I acknoweldge that 'the marketplace of ideas' is a dangerous fallacy; and that climate change is not a hoax, a false alarm, or a potential benefit to humanity:
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  26. I suspect if human activities were a net cooling effect over the 20th century, deniers would be saying increased cold snaps are a good thing, based on similar 20th century data. Central air conditioning usage through the 20th century has increased, from near zero to around 50%, aside from other cooling technologies. Advanced or central heating has had a similar (if not greater) jump. Most of the former changes are not a result of adaptation to global warming any more than the latter, so using 20th century trends in industrialized countries as evidence that increased heat waves are a good thing for mortality is not supported in the data. Basic cause-effect fail. -1 Chip. Adaptation is not without costs either, particularly burdensome for those who are not currently prepared. For those who are prepared, with AC in their homes, vehicles, and place of work, will heat-related mortality stay constant? This relies on the assumption that no one ever goes outdoors for long.
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