Death by Heat Wave

Since the turn of the millenium, we’ve been struck by some truly notable and very damaging heat waves. Probably foremost in the memory of those who follow such things are the 2003 European heat wave, 2010 in the Moscow region, and just this year in the U.S.

Those heat waves are very hot summertime events. But depending on what one calls a “heat wave,” it can strike at any time of year. The World Meteorological Organization defines a heat wave as when “the daily maximum temperature of more than five consecutive days exceeds the average maximum temperature by 5 °C (9 °F), the normal period being 1961–1990.” By this definition they can happen at any location during any season, even wintertime in Antarctica.

A different approach is to define a heat wave by an absolute rather than relative temperature threshhold. Wikipedia reports:

In 1900, A. T. Burrows more rigidly defined a “hot wave” as a spell of three or more days on each of which the maximum shade temperature reaches or exceeds 90 °F (32.2 °C). More realistically, the comfort criteria for any one region are dependent upon the normal conditions of that region.

Heat waves are one of the most dangerous aspects of global warming, as is emphasized in a new report from the World Bank. The danger is well illustrated by showing the impact of the 2003 European heat wave on daily mortality in France. Here’s the excess mortality, i.e., the number of deaths above what would otherwise be expected, along with a plot of daily high and low temperature (in Celsius):

Temperatures above 30°C (86°F) are associated with increased mortality, so the previously mentioned threshold of 90°F (32.2°C) is a reasonable level to indicate enhanced heat stress, at least in this region. Note also that during the peak of the heat wave when daily high temperature hovered around 35°C (95°F), mortality increased steadily in spite of temperatures remaining relatively constant. This illustrates that the longer a heat wave lasts, the deadlier it becomes. At its worst, this heat wave caused an extra 2200 deaths per day in France.

To determine the frequency and duration of heat waves, I took daily high temperature data from the European Climate Assessment and Dataset Network, then noted the occurence of heat waves according to the above definition (at least 3 days with temperature of at least 32.2°C). To gauge the extremity of heat waves, I computed “heat wave degree-days” as the accumulated total excess temperature (above 32.2°C) throughout each heat wave. Then I computed both the number of heat wave days, and the total heat wave degree-days, for each year, for every station which had at least 30 years of data with at least 300 daily observations per year.

I also restricted the analysis to stations which had actually had a minimum of heat waves (which leaves out Greenland for instance), requiring at least one heat wave during at least two years, and at least two heat waves during at least one year.

The results show just how unusual the 2003 European heat wave was. Here, for instance, is the number of heat wave degree-days from the data for Carcassonne, France:

Note how total heat wave degree-days during 2003 dwarfs that during any other year. The same is true at Nimes:

There’s something else to pay heed to: that although 2003 is the only astounding heat wave year observed at these locations, nonetheless heat wave activity has remained elevated. Even if we eliminate 2003 from these data records there’s still an increase in heat wave activity — and the extremity of 2003 cannot be denied.

The 2003 heat wave didn’t just affect France. It’s also evident in data from Spain:

and from Italy:

One of the most astounding data sets is that from Milan, Italy. It stretches back to the 1700s and shows, not just how remarkable was the 2003 heat wave, but how heat wave activity has “taken off like a bat out of hell” since 2000:

Like a bat out of hell, indeed.

As unprecedented as was the 2003 European heat wave, the Russian heat wave of 2010 was even more remarkable. It hit hard — very hard — in areas that don’t (or should I say “didn’t”) usually suffer from heat waves, like Moscow:

Some areas which had no previous heat waves on record have changed that since 2000, such as Voru in Estonia, which not only suffered from heat waves in 2010 but also in 2007 and 2001:

Even some areas which do regularly experience heat waves have seen them get worse since 2000, with 2010 a monster year:

I emphasize that the heat wave record isn’t just about the monsters of 2003 and 2010. It’s also about singificant increase over time, especially during the “modern global warming era” since about 1975. Here, for instance, is the data from Tortosa, Spain:

Bearing in mind that the risk from heat waves involves not just their extremity but their duration, note that the number of heat wave days has also steadily increased at this location:

They used to average fewer than 10 heat wave days per year. Now it’s over 50.

A total of 468 of the ECA data sets met the data selection criteria (minimum amount of data and of heat waves). I tested for statistically significant change in heat wave degree-days, albeit rather crudely, by linear regression on both the number of heat wave degree-days, and on the rank of heat wave degree-days. Of the 468 total, 15 showed a significant decrease in heat wave degree-days. That’s 3.2% — but in fact you would expect 2.5% to do so, simply by random fluctuation, for a test at 95% confidence — so the result is perfectly consistent with nothing more than random variation on a large number of samples. However, 197 out of 468 — fully 42% — showed significant increase in heat wave degree-days. That’s a helluva lot more than you could possibly get from random fluctuation.

As bad as it is already, the heat wave situation is going to get worse. Far worse. In the future, according to projections, most of the world will see a huge increase in the number of 3-sigma hot summers by 2080 (top panels):

Under “normal” conditions, a “3-sigma” hot event would only happen in 1 out of 740 years. Imagine a future in which most of the world suffers what used to be a once-in-ten-lifetimes hot summer, most years.

Perhaps most troubling is the large area that will experience 5-sigma hot summers. That’s something that under “normal” conditions would only happen once out of 3.5 million years. We’re headed for a future in which, for large areas of our planet, what used to be a once-in-a-million-years hot summer has become the “new norm.”

We’re headed into winter in the northern hemisphere, so temperatures are dropping and we’re preparing for the oncoming cold. That makes it all too easy to forget the heat waves we’ve suffered in the recent past, and to ignore the danger they bring. The dead remember.

Let’s not forget the risk of heat waves until the next one hits, who knows where, causing more thousands of unnecessary deaths.

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56 responses to “Death by Heat Wave

  1. Didn’t know where else to ask this, so please feel free to NOT post it, but I’m in a war of words with a denier over this paper..

    ..and before I rewrite books, it seems to me I saw it debunked somewheres..was it here? Thanks, T!

    • Principia Scientific International is ‘fake’ publisher, or vanity science journal publisher. The two main works are the above and one on the human eye are both by Miatello, who has no bio, or is perhaps a chess player. They are junk so don’t waste your time. I’ll put up a post on so others don’t waste their time [plus any additional info]. Principia Scientific int has no web page now but you can see the cache.

    • Harry, PSI was founded a few years ago by, among other AGW deniers, John O’Sullivan and Tim Ball, two of the most dishonest people around. They have absolutely no science background (and I include Tim Ball in that category) . In my view it is just an organization set up to make money from the AGW controversy. Do not waste your time on anything put out, endorsed or supported by that band of dishonest people.

    • Philippe Chantreau

      Harry, this is not a “paper.” Itis not peer-reveiwed, or subject to any other scrutiny for that matter. Prinicipia whatever is not a real science publication.

      • I actually kinda/sorta knew this, Bernard, and was just looking for a complete extant takedown on this crappy paper, before doing it myself. As Quiet Waters has suggested, let this be the last on that question, and thanks to all for additional information. If anyone else cares to weigh in, please do it off this thread, to my email.

    • Just to add to what Jules says…Principia is responsible for the “Dragon Slayers” book and for a lot of nonsense about the greenhouse effect from Postma, Nahle, etc. I haven’t had the stomach to read this piece by Miatello but you can tell your correspondent that denying the greenhouse effect means you are disagreeing with the entire climate science community, including AGW “skeptics” like Roy Spencer (and Willis Eschenbach, if he frequents WUWT), and countless physics textbooks. (Both physics textbooks we use in introductory physics where I teach talk about the greenhouse effect and global warming.)

      We actually tried to have intelligent conversations with Postma at Judith Curry’s blog but that proved to be impossible. The guy is either batshit crazy or purposely misleading people.

      You can then encourage him to be sure to tell any scientists he speaks to of his opinions on the greenhouse effect since that will allow them to instantly assess how seriously to take any of his opinions on any matter related to climate science.

    • Principia Scientific appears to be real crack pottery.

      I was able to find:

      Although broken, there is supposed to be a link to Oliver Manuel’s Scientific Genesis: 2. Origin of the Solar System (1975) where he asserts that the scientific community is dogmatic, the sun has a neutron star core and is made primarily of iron, and that the Earth’s climate is due to the giant planets jerking around the neutron star at the center of the sun. I won’t go into Manuel’s personal history except to say don’t go digging if you’ve just eaten.

      Looking at the Miatello paper you linked to, the second paragraph of the introduction references well-debunked articles, beginning with Gehrlich & Tscheuschner, extensively debunked over here in the links:

      But looking at the argument in the Miatello paper itself, the third and fourth paragraph of the second section state:

      The conceptual cornerstones of this theory, therefore, are essentially two: (i) the idea that the so-called “greenhouse gases” may “trap” outgoing IR radiation from Earth’s surface and (ii) the assumption that IR radiation would be “sent back” to Earth’s surface by greenhouse gases (termed “backradiation”), thereby increasing temperatures.

      Both concepts are gravely mistaken and unsustainable, as they violate very basic laws of thermodynamics (LoT). (i) The 1st LoT, the principle of energy conservation, is violated because, if “backradiation” was able to increase the initial temperatures, additional energy would be created out of nothing without introducing any work from outside the system. (ii) The 2nd LoT indicates that a cooler body cannot add thermal energy to a hotter body by simple radiative “reflection.” The Clausius statement of this law reads, “No process is possible whose sole result is the transfer of heat from a body of lower temperature to a body of higher temperature.”

      I won’t go into the details of how he misconstrues the role of backradiation in the greenhouse effect as I have done so elsewhere. Simply pointing out how he misapplies the first and second laws of thermodynamics should be more than sufficient.

      Under equilibrium conditions, the rate at which energy leaves the climate system is equal to the rate at which energy enters the system. An enhanced greenhouse effect results in an imbalance between these two rates by reducing the rate at which energy escapes the atmosphere. First, by the principle of the conservation of energy (the first law of thermodynamics), if the rate at which energy leaves the system is lower than the rate at which energy enters the system, then the amount of energy in the system has to rise. This is what results in rising temperatures.

      Second, this warming effect does not violate the second law of thermodynamics any more than insulation does. Starting with a house with a furnace such that the heating of the furnace maintains the temperature of the house by generating heat at a rate that compensates for the loss of heat to the outdoors, add insulation to the house. This will reduce the rate at which heat escapes even though the insulation is generally cooler than the house and furnace. Assuming the furnace continues to generate heat at the same rate as before, the temperature of the house will rise. (Eventually the temperature of the house will rise sufficiently that, despite the insulation, it will lose energy to the environment at the same rate as before, balancing the rate at which thermal energy enters the system. A new equilibrium will thus be established.)

      If Miatello were correct, insulation would violate the second law. Blankets couldn’t possibly work. But we insulate houses without any problem, and blankets keep you warm on a cold night. In terms of the analogy, the generation of heat by the furnace plays essentially the same role as the absorption of the sun’s radiation and the conversion of this energy into heat at the surface of our planet. Greenhouse gases perform the same role for the climate system as insulation performs for the house.

      The physics of behind the greenhouse effect is easily studied within a lab. We are able to image carbon dioxide in the atmosphere by means of satellites due to its reducing the rate at which thermal radiation escapes to space. And we have understood that increasing the concentration of carbon dioxide in the atmosphere would increase the temperature at the surface for over a century and a half. Arguing against it is about as rational as denying that microwave ovens work. For more regarding the greenhouse effect, please visit this link.

      I hope this helps.

    • Horatio Algeranon

      “Printcrapia Slyentific”
      – by Horatio Algeranon

      Printcrapia Slyentific
      Is really quite terrific
      A brand new tonian journal
      Of physics gone infernal

      • It’s a shame that such a striking blog post has such a long OT discussion at the head of the comments. Any chance, now Harry has received such detailed responses, that this thread can be deleted/moved elsewhere so the discussion can focus on the post?

    • There was an October 10 posting at principia.scientifc that said that the upper atmpspheric temperature is a vector. The posting seems to have been pulled, but it should give you an idea of how misleading the title of the website is.

      • Yes: I have known for quite some that Principia is to science what Julia Childs cooking has to low fat dieting..;)

  2. and all with just a 0.7c increase and 2c is supposed to be the safe limit!

  3. Hi Tamino,

    I just saw this out in Nature (there is also a News and Views about it)- on an analysis that indicates that droughts have not increased over the last 60 years. I expect there will be some comments about it that can illuminate what these results mean, but it may not be quite out there yet for people to begin discussing.

    • Hard to believe. Certainly contradicts my research. But I could be wrong–and frankly, I hope to Christ I AM wrong.

      • Rattus Norvegicus

        They have included a potentially superior method of calculating potential evaporation for the PDSI. Of course the paper awaits post publication evaluation, but it appears promising. However, this does not mean that predictions of increased drought in the future are toast, merely that we are not yet seeing the effects. Somehow though, I have to wonder, given the observed droughts which have caused major crop failures over the last few years.

      • David B. Benson

        Barton Paul Levenson — Try using the improved PDSI based on (what is claimed to be) a more accurate physical model. For more links and hints about drought measurements, visit
        where reader Jeffrey Green posted numerous links as he found more info about drought studies. There is also Brett Anderson’s brief statement regarding Dr. Dai’s criticisms of this paper in Nature.

    • Evidence linking Arctic amplification to extreme weather in mid-latitudes

      Slower progression of upper-level waves would cause associated weather patterns in mid-latitudes to be more persistent, which may lead to an increased probability of extreme weather events that result from prolonged conditions, such as drought, flooding, cold spells, and heat waves.

      Have we seen a step change in droughts and floods due to Arctic warming – that’s not in the Sheffield et al. paper?

    • From Joe Romm at Climate Progress:

      Kevin Trenberth, former head of the climate analysis section of the National Center for Atmospheric Research, has sent me a strong critique which is printed below. NCAR’s Aiguo Dai also sent me a critique.

      The new article simply ignores or dismisses a considerable amount of the drought literature and focuses instead on one narrow metric of soil moisture…. I think it bizarre to claim that there is little change in global drought over the past 60 years when there are so many studies and analyses to the contrary directly linking severe droughts to climate change: …
      Climate Change Is Already Worsening Droughts In Many Ways: Nature Gets It Wrong–And Right, Nov 20, 2012

      Romm does not include Dai’s response, but states:

      Dai sent me a long explanation of a major flaw in Sheffield et al, which I’ll summarize as “they normalized away the recent drying.” I think Nature needs to reconcile these papers, but until then, one should probably stick with the large and growing literature on the large and growing rise in aridity over many parts of the world. (ibid.)

      It is my hope that more from Dai will be forthcoming.

    • There is an ongoing discussion in the literature about which drought analysis method is best. Some say the classic PDSI is not useful in a changing climate (like yours), others say the classic still is capable of getting the trends right in most regions with exceptions (Dai 2011, 2012, v.d. Schier et al 2011)

      Although many agree that incorporating a better hydrological and vegetation model in the index would be useful, there is no definitive answer to the trends, as confirmed by IPCC SREX: “there are still large uncertainties regarding observed global-scale trends in droughts”.

      But, ofcourse, drought is not the same as heatwaves.

  4. Jeff Masters blogs of November 16 and 19 2012 cover the subject of heat as well, from the drought perspective. He has also covered the high cost of extreme weather, including droughts recently. Once again I can’t help but be reminded of your post from a while back…”come hell or high water, expect both…”. Unfortunately, nice call.

  5. Horatio Algeranon

    “Heat Wave”
    – Horatio’s sundering of Linda Ronstadt’s Heatwave” (Linda who?)

    Whenever it’s warmin’
    Something outside
    Starts to burning
    And it’s filled with the fire
    Could it be the carbon in air?
    Or is this the way it’s supposed to fare?

    It’s, yike(!), a heat wave
    Burning up the chart
    Can’t keep de-nying
    It’s climate change at heart

    When weather, it is insane
    Hot, blow, sleet and rain
    I feel, yeah yeah
    Well I feel that burning flame
    Has climate change got a hold on me?
    Or is this the way it’s supposed to be?

    It’s, yike(!), a heat wave
    Burning up the chart
    Can’t keep de-nying
    It’s climate change at heart

    Sometimes we stare down from space
    Fires all over the place
    I can’t explain it
    Don’t understand it
    I haven’t ever felt like this before
    Now that sunny feeling has me a-dazed
    I don’t know what to do
    My head’s in a haze

    It’s, yike(!), a heat wave
    Burning up the chart
    Can’t keep de-nying
    It’s climate change at heart

    Yeah yeah yeah yeah
    Yeah yeah oh oh (heat wave)
    Yeah yeah yeah yeah
    oh (heat wave)

    Don’t pass up this chance
    This time it’s NeRomans
    Heat wave
    Heat wave
    Heat wave
    Oooh heat wave

    As an aside, Horatio has “fond” memories of substitute teaching in Linda’s high school in Tuscon, AZ (though years after she was there). It was kind of a wild school. One student gave Horatio a 6 inch knife as “collateral” for a pencil (and actually asked for it back after class!) Anyhow, that’s Horatio’s brush with fame.

    • David B. Benson

      Good. Now please try “So Long, Its Been Good to Know You”.

      • Horatio Algeranon

        Woody was waaaaay ahead of his time and Horatio certainly can’t improve, but can (most humbly) add another verse applicable to this post

        Now, the heat wave came, an’ it went through the roof,
        That was CO2, a-showin’ his proof.
        He said, “Kind friend, kiss your ass goodbye;
        You had your chance and now you’ll die!”

        So long, it’s been good to know yuh…

      • David B. Benson

        Horatio Algeranon — Thank you kindly.

  6. Pinko Punko – Yeah, it’s a common misconception that global warming equals global drying. It’s not correct. Warmer air temperatures do not automatically dry out soil moisture. Vapor pressure deficit, surface solar radiation, and wind speed are the primary factors.

    As far as the last 60 years are concerned, you need to consider the perspective that the amount of surface solar radiation (SSR) varies considerably with the concentration of aerosols, and particularly clouds, in the atmosphere, and that globally there was a long period of SSR dimming from mid 20th century through to the 1980′s, an SSR brightening thereafter, and then a dimmng trend commencing in 2001. These dimming trends will greatly ameliorate the evaporation of moisture from soils.

    In terms of global evaporation; 86% of evaporation comes from the ocean surface, and the oceans have been warming due to longwave forcing of the cool skin layer (i.e more energy from sunlight is trapped in the oceans, causing them to warm). Durack (2012) demonstrates that evaporation from the ocean has increased dramatically over the last half-century, as this is apparent in the strengthening salinity and freshening patterns. So, overall, global precipitation has increased -dramatically, and much more than the climate models predict.

    It’s therefore not that great a surprise that the areal extent of drought may not have changed that much in 60 years. But this doesn’t mean drought is not a problem for the future. The expansion of the subtropical dry zones will afflict grain-producing regions in Australia and the United States, for instance. Also, the continued warming of the atmosphere will increase its moisture holding capacity, which will create larger differences between warm and cool regions (thinking of La Nina & El Nino here), which will in turn drive more extreme precipitation anomalies during ENSO. In other words El Nino will become drier for most regions, and La Nina wetter. This will prove hugely problematic to agricultural production.

  7. Timothy (likes zebras)

    Is it possible to say whether the increase in heat waves is what you would expect from an increase in mean temperature?

    Or is there evidence that the increase in heat waves is greater/lesser than you would expect, thus indicating an associated change in atmospheric circulation that is creating more extreme weather – i.e. the idea colloquially referred to as “Climate Chaos”?

    • David B. Benson

      There is the distinct possibility that increased average temperatures also have increased variance. So extremes become more common.

  8. Rob, warmer temperatures mean more evapotranspiration. If winds are shifting air out of an area, and incoming wind is not particularly moist, the area must dry out. Conservation of mass.

  9. Gavin's Pussycat

    One aspect of this analysis that bears thinking about is: are these spike-like heat waves a good model for what permanent warming-up (and heat waves on top of that) would do?

    Humans are actually pretty good at adapting to a wide range of average temperatures: they live in all climate zones. Part of this adaptation is physiological (takes no more than a year or so living in a place), part undoubtedly is cultural (clothing) or technological.

    The place where I see this running into the wall is the tropics. If it gets warmer there than it has ever been anywhere on Earth for millions of years, all bets are off.

  10. Interesting analysis. It’d be good to accompany it with an analysis of deaths avoided ( postponed) in warmer winters. Which is not to say this isn’t a problem especially on the regional scale, but it’s an obvious response from some …

    • That supposes that ‘warmer winters’ save lives. One might pretend that warmer winters mean less cold, more snow, more melt and more deaths.
      Or that warmer winters kill less bugs and pests, and wreak even more havoc on the farms and woods (pine beetle, anyone), causing indirectly more worries and more deaths.

      • Which is *precisely* the situation, here in Colorado, that led to our terrible fire season of 2012. Our lodgepole forests–and those of all the surrounding states, to the north–are in a huge die-off, because of the warmer, shorter winters making it possible for pine beetles to thrive. In some places in Colorado, almost 100% of the lodgepole are dead or dying.

      • And it’s the same situation in the Northern Rockies well up into Alberta and BC…that lead to the continuation of Colorado’s fire season up here into early October. We had smoke in Montana for almost two months.

      • I’m not supposing anything; I was suggesting that the issue was worthy of analysis. If one is going to argue that death is a metric, then we should do it over the entire year, not only over one season. Personally, I’m far more concerned by the ecological impacts (and consequences) since I suspect that they’re probably negative all year round, whereas, I *suspect* the same isn’t true of the human death rate, at least in some regions – but it’d be nice to know (within the bounds of what the data might or might not tell us).

    • One largely unexamined aspect of warming winters for fire prone regions like much of Australia is how that will affect “controlled” hazard reduction burning done during cooler weather.

      Whilst heavy fuel accumulations in Australian forests will go on burning in cold weather in anything short of serious rain, there’s been an unstated reliance on cool overnight conditions, with the dampening effect of dew, to largely self extinguish grass fires or those in places without a heavy fuel load. If they aren’t contained or extinguished they inevitably find their way into areas with heavy fuel loads.

      Lots of uncontrollable bushfires start as ‘controlled’ ones on grazing properties, where burning off dead grass is done to improve grazing conditions as much as to reduce fire hazards, with little equipment, manpower or backup – because, if weather conditions are right, they self extinquish or are significantly reduced in intensity enough not to jump vehicle tracks or other firebreaks. The ‘right’ conditions tend to be low wind and cooling overnight to below dew point.

      If overnight temperatures are significantly warmer, larger areas will simply fail to get below dew point temperatures; that reduction of fire intensity won’t happen and the manpower, equipment and logistics of safely burning off fuel load accumulations rises greatly. I expect large areas will miss out as the window of opportunity is narrowed or disappears. The real impact of that will be the intensity of wildfires later, when it’s hot, dry and windy. Like the record heatwave conditions preceding the horrific and unprecedented fires in Victoria a few years ago.

      I can’t see warmer winters here being a good thing.

  11. Tamino, thank you for this analysis, it’s sobering. Question: if you homogenise and grid the temperature data, would you get the result that Hansen presented in his Climate Dice paper?

  12. > lodgepole forests

    “cold tolerance varies within a season, among seasons, and among geographic locations depending on local climate. Beetles build up materials in their bodies that reduce the risk of ice formation. These materials develop over time as the larvae are exposed to increasingly colder temperatures during the winter. This process of becoming acclimated to cold is driven by daily changes in temperature. Sudden drops in temperature, especially in early and late winter, have the greatest impact on MPB mortality. Gradual cooling, even to very low temperatures, has little effect.”

    The biological controls described on the same page — wasps, flies, and woodpeckers — are less effective during the outbreak stage of the pine beetle, but if protected and encouraged to increase, there will be more of them around to maintain control afterward. That means leaving some snags and otherwise protecting some areas of infested lodgepole from both fire and mechanical removal.

    Nature does better with edges and patches, not clearcuts.

  13. Thanks for the analysis – the Milan record is extraordinary.

    This summer’s heat wave was a real wake-up call for me. I already understood the severity of climate change in abstract terms and as a chronic issue, but now I see it also in more concrete terms of catastrophic events. It was very interesting to look deeply into the ways that climate change affect us, sometimes mundane (my friend lost his dog to heat exhaustion) sometimes unusual (who would have thought that heat waves could make trains derail?)

  14. Without meaning to be callous or disputing the overall seriousness of the warming, everyone has to die eventually, of something. If the excess deaths during the heatwaves were of people who were in very fragile health and who would have died fairly soon anyway, then perhaps it is less significant than it seems.

    Perhaps one could think of it like a tree in autumn still covered in leaves, but about to fall off. If the wind blows, the leaves will all fall, and the immediate cause would be the wind. However, the leaves would have fallen anyway within a few days.

    • Not a good analogy, Ed: the falling of the leaves in autumn is an entirely natural event. now, let’s do a bit more analysis, shall we? I live in Colorado, and when it snows early in the fall, before the leaves have turned–and this is as a result of autumn arriving about two weeks later than is historically normal, due to AGW–the leaves trap the snow, and break off large branches and in some cases, toppling entire trees.

      Well, those trees would have someday died anyway, right? Right…BUT they are now damaged, sometimes beyond saving them, largely due to an UNnatural forcing, as it were.

      Your example sounds much like the denialati’s often-trooped-out trope of, “well, we’re all gonna die *anyway*, so why bother trying to stave off disaster?” Sorry, Ed, but that dog don’t hunt, as we say in these parts. *WE have been the proximate cause of much of these extra-normal events and as such, we are beholden to try to slow the inevitability of the damage we have caused. No, thanks largely to the efforts of Big Oil and Big Coal, and their acolytes, we cannot now save as much as we could have, had we not been thwarted from doing so 30 years ago; however, it would be immoral of us not to try.

    • Ed wrote:

      Without meaning to be callous… If the excess deaths during the heatwaves were of people who were in very fragile health and who would have died fairly soon anyway, then perhaps it is less significant than it seems.

      Not sure whether individuals in frail health correspond in your analogy to the individual leaves or to the trees. In your case I suspect its the leaves, but in HarryWiggs’ case the stressed trees, where the trees themselves may fall. But if I may, another useful analogy might be sea ice lost during the melting season.

      Some first year sea ice might be lost that would have gone on to become second and third year sea ice. For example, the very young are more vulnerable but would have become stronger with time. It is afterall the very young as well the very old and chronically ill that are more susceptible to the extreme heat. If, looking simply at the increased number of deaths or higher death rate is viewed as somewhat misleading as it treats everyone the same, failing to take into account how many days they have left, then this omission cuts both ways, doesn’t it?

      There is another way in which an analogy with sea ice might work. We can measure sea ice in terms of area or volume. Area would be what is at the surface and is easiest to measure. Volume is more difficult to measure and somewhat less visually striking. Or to put it another way, volume is less immediate.

      You could measure the human cost in terms of individual lives, which would be the sea ice area, or you could measure it in terms of volume, which would be the number of human days that are lost, the latter of which is more difficult to estimate or measure. Yet volume would seem to be a better measure, if one can accurately measure it, and afterall, my time is worth as much as the next person’s..

      There is another way in which this sea ice analogy might work. Just as some ice may be made thinner by an especially severe summer, such that it is more likely to melt out the next summer, even though that summer may be less severe, some people may be severely weakened by an especially strong heatwave, such that they won’t as easily make it through the next summer, even if the heatwaves of the next summer are far less severe.

      For example, due to the high heat, a cardiac patient might have a heart attack where some of the tissue dies, rendering them more susceptible to next summer’s heat or even a winter’s flu. I suppose that, in the analogy, what might correspond to the flu is the mixing of sea ice with the warmer water from below due to the wave action of a passing storm late in the season, when refreeze has already begun. The easiest metric, whether it is sea ice area at the sea ice minimum or excess deaths during the heatwave, won’t capture this, as it is concerned only with the losses that happen at the time of the extreme heat, Nevertheless, these are losses that are at least indirectly attributable to the extreme heat.

      It also helps if we keep in mind that we are facing a trend of increasing temperatures. Some melt seasons and heatwaves will be much worse than those that immediately follow, but with time, what constitutes a “normal season” will be worse than what would have been considered especially extreme only a few of decades before.

    • As Harry Wiggs notes, the analogy with autumn leaves is poor.

      Essentially what will happen in a world that is several degree warmer is that the life expectancy of whole populations will decrease, all other things being equal. Just because the weakest succumb first doesn’t mean that there’s not a genuine life-reducing phenomenon occurring. And physical vulnerability doesn’t mean that all affected wouldn’t have survived to live long lives had the heat wave not occurred.

      Ask someone who lives in the tropics if they wouldn’t care if their baby died in an extreme heat wave that resulted directly from humans having increased the temperature of the planet by four degrees, and I suspect that they’ll look at you as though you were psychopathic.

      Ask any human if they’re happy to have their life expectancy reduced and I suspect that they’d say no. Of course, the rest of the biosphere would probably cheer at the idea…

      It’s also important to realise that in extreme drought in some parts of the world, even the robust of health are at risk.

      If you want to use the autumn leaves analogy, it’s better framed by saying that the colour turns earlier: in other words, the tree’s period of greeness (and hence of active photosynthesis) is shortened. And for a tree that is Not Good, just as most humans regard curtailing of their own lives as undesirable..

    • With all the negatives you’re getting Ed, let me just say I think your analogy is a good one, as these things go. But our prediction is that the wind that blew off the leaves is just the outermost edge of a hurricane coming to blow off the rest of them.

      • Thanks Greg, I was not disputing that humans are warming the Earth and this is not a good thing either for man or nature, which is why I was careful to say it, simply that I’m not sure excess deaths during a heatwave in France are necessarily one of the best examples.

        It also opens the doors to the type of denier who argues that warming will be a good thing as fewer people will die of cold in their imagined Eden-like future world. The BBC has a story today that the winter death rate in England and Wales was down 8% for the winter of 2011-12 due to less flu about and milder weather. It doesn’t logically follow that I think we should be pumping out more GHG…

    • Ed: “Without meaning to be callous or disputing the overall seriousness…”

      Oh yeah, that’s a good one. Here are a few more:

      1)With all due respect…
      2)This isn’t about money, but
      3)Far be it from me
      4)I’m not racist, but
      5)I’m not sexist, but
      And the ever popular southern phrase
      6)Bless her little heart.

  15. Ed | November 23, 2012 at 1:49 pm | Reply

    “Without meaning to be callous or disputing the overall seriousness of the warming, everyone has to die eventually, of something. If the excess deaths during the heatwaves were of people who were in very fragile health and who would have died fairly soon anyway, then perhaps it is less significant than it seems.”

    Without meaning to, but succeeding wonderfully just the same.

    • Yep. That way lies a calculus of values that rapidly becomes extremely unpalatable. I lost my mother when she was 86. What would the value have been of some arbitrary extension of her life–and to whom? To her, to my brother and myself, to society in general?

      Our collective technological prowess forces us to play God, although clearly we are not very good at it. My gut says that, absent some compelling pragmatic reason–say, inescapable decisions about the allocation of medical resources–questions about whose life and whose time is ‘more valuable’ should remain unanswered–better, unasked–in the policy realm.

      Better to devote the energy to questions we *must* answer, and answer well. Such as allocating responsibility for mitigating GHG emissions optimally.

      • Horatio Algeranon

        There is also a socio-economic dimension.

        If Horatio’s grandmother could afford AC , while yours could not, does that mean Horatio’s grandmother deserved to live through a heat wave while yours did not?

        You are so right, Kevin.

        This kind of “moral calculus” makes the tensor calculus of general relativity seem like child’s play by comparison.

  16. On a more scientific note, this comment – “If the excess deaths during the heatwaves were of people who were in very fragile health and who would have died fairly soon anyway, then perhaps it is less significant than it seems” – is essentially trying to extract meaning from a tautology.

    Excess deaths from heatwaves are always going to be old, frail, sick or otherwise vulnerable (eg homeless, poor) people.

    They are significant.

    Borrowing from Niemöller:

    First the heat waves killed the old
    and I did not speak out
    because I was not old.
    Then the heat waves killed the frail
    and I did not speak out
    because I was not frail.
    Then the heat waves killed the sick
    and I did not speak out
    because I was not sick.
    Then the heat waves killed the homeless
    and I did not speak out
    because I had a home.
    Then the heat waves killed those who could not afford air conditioning
    and I did not speak out
    because I could afford air conditioning
    Then the heat waves killed me
    and there was no one left
    to speak out for me.