HEAT STROKE: When Heat Kills

Radio Ecoshock June 11, 2010



While oil gushes out of the Gulf, and the economy staggers toward the exits, scientists continue to investigate our longer future.


For example, could it get so hot that large parts of the heavily inhabited Earth would have to be abandoned?And I ask two popular bloggers, why are most of the public blissfully unaware of how heat kills?Do you know the operating temperature of your skin?No, it is not 98.6, or 37 degrees C.


Scientists predict more extreme heat waves, as the planet warms.They are already happening, with more records set in the North America, Europe, Asia and Australia every year.Pakistan just set a new all-time record - over 53 degrees, or 129 Fahrenheit.Over a thousand people just died in India from heat stress.And this, on the Hellish heat wave in Pakistan.


Who goes first?If you guessed the elderly, you are only partly right.Babies and teenagers are on that list.And anyway, won't all of us be seniors someday, as the heat increased?


Never mind.You and I will have air conditioning.Until the power goes out, as it regularly does during heat waves.


And despite all the images on TV, heat kills more of us than tornados, hurricanes, or lightening, combined.


We'll thrash through that with John Cook, the Australian host of the Skeptical Science blog, and then with Stuart Staniford, a techie and energy specialist writing in the Early Warning blog.Then, for something completely different, scientist Mark Moffett tells us how ants adapt to climate.When I hear these bugs have agriculture, including pesticides, I begin to wonder if ants are the next civilization, after us.


Listen to this week's program for our three interviews.And get all the links you need to follow up in our extended blog entry below.


Of course there are sensible things we can do, to stay alive in the coming heat waves, and stop cooking our grandkids.Like getting off fossil fuels very quickly.Changing over our cities from heat sinks to natural cooling centers.And using community planning to care for those most at risk.We'll have to save that for a future Radio Ecoshock program.


What if Earth becomes too hot for humans to function outside? Science fiction?Or real science?Let's investigate with Australian blogger John Cook.His well-known blog is called "Skeptical Science." John studied physics at the University of Queensland, Australia. He is not a climate scientist, but relies on peer-reviewed papers by other scientists.


Like many of us, John was drawn to a startling new paper recently published in PNAS, the Proceedings of the National Academy of Science.It combines work by an Australian, Dr. Steven C. Sherwood, from the University of New South Wales, and the American scientist Matthew Huberb, from the Purdue Climate Change Research Center.


Sherwood and Huberb investigated the upper limits of human survival, in a warming world.Their paper is called "An adapt-ability limit to climate change, due to heat stress."They said there is a possibility that by 2300, Earth could be too hot for humans.


Here is a list of the highest temperatures ever recorded.


Before we can go much further, we need to explain the difference between "wet bulb temperature" and the common numbers we see in a thermometer.Take a standard thermometer, and wrap a wet cloth around it.Then hold it up in the air, where whatever ambient air currents can flow over it.That cools the bulb, according to the surrounding humidity, and the air movement � and the result is the �wet bulb� temperature.Usually it�s cooler than a dry bulb measurement.Scientists have a more precise way of doing it, but you get the idea.


That wet bulb temperature is going to tell you a lot more about how we humans, and other animals that need to sweat to lower our body temperatures, react in the real world.


The authors of this new paper say, that going over 35 degrees in wet bulb temperature - that's 95 degrees Fahrenheit in humid conditions - for extended periods, should induce hyperthermia, commonly known as heat stroke, in humans.


But right now on Earth, we seldom exceed 31 degrees of wet bulb temperature.So why worry?Well, as we burn more fossil fuels, and disturb the greenhouse gas balance in other ways (like deforestation and agriculture) � scientists predict the Earth will warm up several degrees, over the next hundred to three hundred years.


These two scientists envision real trouble, when the mean global temperature goes up by 7 degrees C, which is predicted by many scientists, if we continue to burn fossil fuels as we do.Nobody knows how soon that will be.


But we are already seeing thousands of heat deaths in North America, Europe, Asia, and Australia.We don�t have to wait for the long-term future.


Here is a link to John Cook�s article on the science, posted May 11th, 2010.




I talked with John about the mechanics of how we stay alive, or not, during extreme heat events.Can you tell us about our inner core temperature, versus the heat exchange at our skin?It turns out that our skin needs to be no hotter than 95 degrees F. or 35 C.We modulate our internal temperature by sweating.The evaporation keeps us cool � so long as the combined temperature and humidity don�t overwhelm our system.


So, the kind of environment matters a lot.Being hot in a desert is much different from heat waves in a humid place.It turns out some seniors lose the ability to sweat well, which puts them in danger.Small children and babies have a poor ratio of skin to body weight, so they can be at risk.


And some medications used to treat mental illness, like depression, can also inhibit sweating.Older research in the 1970�s, before widespread institutional air-conditioning, found psychiatric patients were twice as likely to die of heat stress during heat waves.That included those who were taking no medication at all.I don�t know whether that is because disturbed people tend to move around more, or fail to take simple steps that would have cooled them off�


John Cook had the unpleasant realization that the growing impact of heat stress could be much more devastating to our civilization, than rising seas.That is because our two scientists provided a map showing much of South America, most of Africa, and a lot of Asia would be too hot for normal human survival by the year 2300 � or at least there was a risk up to 10 percent that could happen.Of course, that presumed the worst case scenario of burning fossil fuels, and a 12 degree C heat rise.We are on track for that worst case scenario right now.


Looking at the map provided by Sherwood and Huberb, they seem to suggest that most of Australia would become uninhabitable, if we burn all the fossil fuels, including Australia's coal.And yet Australia is ramping up it's coal exports.John says the public is unaware of the extreme risk � of making most of the continent useless for human life.And the politicians are just looking at the next election, rather than the long-term viability of the country.


John has accumulated a good community of commenters on the Skeptical Science blog.One entry that caught my attention said, quote:


"The difficulty with air conditioning is that most household air conditioners are only rated up to about 41C, some to 43C, I think. When the temperature rises to 51C for any length of time, like a summer heat wave, we'll either have to invent better air conditioners and de-humidifiers, or find another way to keep cool. (That's only 4C warmer than it got to in the heat wave in Melbourne in southern Australia last year - and the global temperature is still climbing.)"

end quote


There may be limitations to the fall-back strategy of air conditioning, not to mention the increased load often leads to power failures, anyway.


We talk about some of the more recent heat events in Australia, which have been extreme and deadly.




According to the American National Center for Atmospheric Research, over the past decade, daily high record temperatures in the United States outnumber record lows, by two to one.Record heat is becoming the norm.


John Cook, when scientists speculate fossil fuels could drive us to the upper limits of human tolerance for heat, deniers routinely fire back ideas like "scientists can't predict the weather next week, so why should we believe anything hundreds of years from now".How do you answer that?


John gives us a good explanation � because that is one of his specialties: answering the twisted logic of climate deniers, while gently explaining science for the rest of us.


As I talk with climate scientists, and research heat deaths, I suspect we may not reach this limit 300 years from now, but much sooner.Already, we face an on-going series of heat challenges, like the hundreds dead in Chicago in 1995, and at least 35 thousand killed by heat in Europe in 2003.Links to many reports on that 2003 death wave can be found here.And of course Wiki has a whole entry on heat waves.Over a thousand people died in just one state of India in 2003, so the heat that hit Europe also went to Asia.



At the same time the heat was killing in Chicago in 1995, it was also causing deaths in England and Wales.A large portion of the globe was enveloped in heat � and that may be a greater fear in the future � semi-global heat waves.Just consider the economic impact alone, much less the lives lost.


There are a couple of under-reported aspects to the French deaths in 2003.First of all, the public health system, namely the doctors and hospitals, were unprepared and over-whelmed.Second, it is possible that up to half of the deaths were caused by low-level ozone, smog, which creates breathing problems and heart attacks.But the smog was made worse by the heat, so these are still heat-related deaths.


Right now, thousands more have died in a killer heat wave in Pakistan and India.


Don�t forget the 2006 heat wave in the United States, or the killer heat in Eastern Europe in 2007, which caused 500 deaths in Hungary alone.


I just think deadly heat is already underestimated when we talk about global warming.


It isn't as though we aren't being warned by scientists, or even governments.Here are just a couple of paragraphs from a U.S. government web site, quote:


"For example, by the end of this century, the number of heat-wave

days in Los Angeles is projected to double,284 and the number in Chicago to quadruple, if emissions are not reduced.


Projections for Chicago suggest that the average number of deaths due to heat waves would more than double by 2050 under a lower emissions scenario, and quadruple under a high emissions scenario.


A study of climate change impacts in California projects that, by the 2090s, annual heat-related deaths in Los Angeles would increase by two to three times under a lower emissions scenario, and by five to seven times under a higher emissions scenario, compared to a 1990s baseline of about 165 deaths. These estimates assume that people will have become somewhat more accustomed to higher temperatures. Without such acclimatization, these estimates are projected to be about 20 to 25 percent higher."


end quote.


The same thing for Australia, where Dr. Martin Cope of CSIRO says the current thousand annual heat-related deaths will swell, as heat and smog waves increase by about 20 percent, in just the next 50 years.It's coming mate.


The public is so unaware of this growing danger, until it happens on a massive scale.




Let me go further on the idea that we could leap to the upper limits of human survival, much faster than 300 years from now.


Other factors could speed up areas made dangerous by extreme heat.Justtake the latest Arctic ice predictions, from Wieslaw Maslowski of the Naval Postgraduate School.Arctic ice, he says, will be almost gone in Summer, before the end of this decade.Joe Romm at climateprogress.org calls it "the Arctic Death Spiral" - and that certainly means more rapid heating will come.


Other scientists are plainly freaked out by two studies showing ocean clathrates melting in the Arctic.That could lead to a methane burst, and a big jump in heat.The possibility of a sudden jump in global temperatures, would find us unprepared for a new regime of seasonal heat waves.


Science has found past examples of a four degree temperature rise in less than a decade.


I think it's possible we could find some parts of the Earth uninhabitable even by 2100, within the lifetimes of our grandchildren.


The Washington Post reports we are on track to reach 6.5 degrees Fahrenheit of warming, even if we stopped polluting right now.




Television gets our attention with photos of the latest storm deaths and damage.We just had graphic shots of buildings ripped up by a deadly tornado in Ohio.


But there isn't a lot of stimulating footage of the old, and the young, quietly passing away from heat exposure.Yet more people are killed by heat than by storms, floods, and the like.It seems we have a blind spot when it comes to the heat threat, just as we do with other creeping problems, like rising seas or global warming generally.


We haven't even discussed the impact of heat waves on agriculture.Last year's combination of heat and drought smashed Australia's farm production.Lester Brown warns that rice is already at the limits of heat tolerance.Just a couple of degrees more, when the plants are setting fruit, and rice crops could fail, leaving millions starving.And what about farm animals, which are mammals, with the same heat problems we have.Isn't it possible that heat waves could lead to starvation, the way cold and frosts have done in the past?


Meanwhile, scientists in Australia predict a surge of heat deaths.


As we finish up, John Cook describes some of the other work he does with his blog.


John has also just started appearing on the new climate podcast "Irregular Climate" with Dan Moutal.He gives a regular two minute bit on climate denial.


From Australia, we've been talking extreme heat, with John Cook, host of the Skeptical Science blog, at skepticalscience.com.




I like people who can dig into problems, and find insights the rest of us miss.That's why I've called up Stuart Staniford.He has a doctorate in Physics, and a Masters in Computer Science.By day, Stuart is Chief Scientist for the computer security company FireEye.By night, he's a well-known energy commentator, especially at theoildrum.com, and on his own blog, "Early Warning".



Stuart�s blog is called "Early Warning, Risks to Global Civilization".An article he posted on May 6th certainly caught my attention, and bounced all over the Net.Really, it was the inspiration for this Ecoshock program.The title is "Odds of Cooking the Grandkids".


["An adaptability limit to climate change due to heat stress" published in the Proceedings of the National Academy of Science (PNAS) by

Steven C. Sherwood,(a) and Matthew Huberb]


Stuart and I talked about the demographics of who dies during heat waves.Of course, most of us will answer �the elderly�.


You know, people shrug off the "old people" part, unless they are old - not realizing - that means all of us, as heat waves become more common in the future.We are all going to be old people, and our lives will matter to us.


For example, here in Canada, the number of people over 65 is expected to double by 2036.Sometime around 2017, there will be more seniors in Canada, than children age 14 and under.


So we could have a lot of deaths.And even those who survive hyperthermia, as heat strokes are called medically - the survivors often have brain damage.They require serious care for years.If heat waves become more common, as some scientists predict, this could be a huge drain on families, and the economy.




In another entry the Early Warning blog, Stuart investigated if there are parts of the world already approaching these human heat limits.He found a possible example in India.That was published before the recent heat waves, with thousands of deaths, that just happened in India.Not to mention the new record high in Pakistan.It hit 53.7 Celsius, or 129 degrees Fahrenheit, at the end of May.


Read this blog entry for a fascinating look into stone quarry workers in the Northeastern part of India.Many of them are already experiencing all the signs of heat damage, working outdoors well beyond human limits.Like the old blast furnace workers, we can expect them to have shorter lives, and some permanent physiological damage.In a way, the studies on these Indian quarry workers could apply to millions of people in the coming hotter world.


You can read �How Does Heat Kill You?� in this Slate article by Daniel Engber.




Another form of denial, is the idea that we'll be fine, due to air conditioning.But that depends upon increasing our energy supply, all over the world, just as we struggle through declining supplies, after Peak Oil.Your work is well-known at the energy blog, theoilddrum.com.Imagine the extra world energy supplies required to air condition India, China, not to mention heat zones in Africa, and South America.


I don�t see that happening � but Stuart isn�t sure.After all, much of the electricity being added in the developing world is still hydro power, or even nuclear.Sadly though, I just read figures from the International Energy Agency showing that about one third of the world�s electricity comes from coal, which only makes global warming worse and more certain.Imagine the horrible feed-back loop if we keep burning more coal to keep air conditioners workings, making a need for still more electricity.A heat loop.


Air conditioning in California adds over 40% to peak production, according to one study.


That isn�t the only problem with A/C as you�ll see below.




I'd like to talk for a minute about the impacts of bad building techniques, when it comes to heat stress.


Here in the West, our buildings depend entirely upon cheap fossil fuels for cooling.In commercial buildings, the floor-to-ceiling glass doesn't include windows that open.There are huge A/C costs already, and conversion of old sky-scrapers doesn't seem likely. Ditto the highly energy-inefficient monster houses that have been all the rage.We built ourselves into an unsustainably hot corner.


The French concluded one factor, in their thousands of heat deaths in 2003 - resulted from traditional building techniques.Heavy stone, brick and cement usually moderated day and night time temperatures.But when the night temperatures only dropped to 90 degrees Fahrenheit, the buildings began to accumulate heat, and couldn't cool off.Neither could the humans inside.


So, buildings can be a huge factor, considering we count on them for shelter.I think we need to learn from North African and Middle Eastern architecture, to make shelters that can cool us, even if the A/C fails, or when energy is prohibitively expensive.But I don't see much talk of that in our building industry, do you?




Let's look at another technical challenge.Our power grids tend to break down when the A/C demand is highest.Let me give just a couple of quick examples.The famous Northeast Blackout of 2003 occurred on a hot August day.It was over 88 degrees, or 31 degrees Celsius. People turning on their air conditioning was a minor factor, in blowing out the whole region, over many States, and in Ontario, Canada.


Again in 2006, British authorities blamed the greater London blackout on increased air conditioning use, during that heat wave.Ditto the 2007 power failure in Serbia and Greece, and the 2009 blackout in the Australian state of Victoria, during a three day heat wave.So, most of us are counting on artificial life support by machines, that may not be there.


Check out the vast blackout of the U.S. Northeast in 2003 here.The power can go out, over giant regions. If it happens during a heat wave, many who thought they were protected will die.


On a larger scale, our cities are poorly designed, becoming heat islands, rather than cooling us down.Even ants know how to make nests that cool. We cut out the green, replacing it with black asphalt.For example, even in London, the UK government's Met Office predicts heat-related deaths will quadruple by 2080.The British also found cities can be up to 18 degrees Fahrenheit, or 10 degrees C hotter at night, than the surrounding country-side. Is it possible that some world mega-cities could become unsustainable, due to heat?Here is more on that from the Times of London.


We didn�t have time to discuss cultural weaknesses, that make us less likely to adapt well to heat deaths.


Here is another discussion of this ground-breaking report on the limits to human heating, from Sherwood and Huber.And scientists have been predicting more frequent and longer lasting heat waves in the coming decades.


I've just talked with another enquiring mind, Jack Alpert.His parting words to me were: "Humans routinely underestimate the challenges we face, and always overestimate our ability to muddle through them."We face a situation which makes it increasingly dangerous to do meaningful activity outside, for an increasing number of days per year?


I asked Stuart Staniford, who has specialized in looking at the big global risks: �Are we going to be able to muddle through?�


Stuart was more optimistic than I am.He thinks that by 2100 there will still be a recognizable version of our current civilization � even though many people and countries will go through terrible difficulties.


When enquiring minds want to know, they often turn to the Early Warning blog, at earlywarn.blogspot.comOr look for Stuart Staniford's work at theoildrum.com, energybulletin.net and many other spots around the Net.He's a scientist and investigator, at the leading edge of many of our biggest challenges.


There are some solutions and mitigation of course.The City of Philadelphia set up a kind of social net for heat emergencies.Chicago has tried to add vegetation and cooling to the city.The U.S. has developed a �heat stress index� found here.The National Weather Service provides a heat wave page.And the EPA has an �Excessive Heat Events� Guidebook.


It�s a huge subject, even though people talk little about it.A search for �heat deaths� on Google found more than 5 million responses.


Because smog during heat waves is such a killer, reducing traffic saves lives.Restrictions during the Atlanta summer Olympics in 1996 cut childhood asthma emergency visits by 42 percent.But governments generally don�t get it � and seldom ban traffic merely to save hundreds or thousands of lives.


Perhaps outdoor workers can wear �ice vests� to cool them down.Maybe humans will only work outdoors at night during the hot season.New heat laws may force regular breaks under cooler shelter.Humans burrow in, as the hot centuries begin�


We will get better at it, but I doubt that kind of organization will reach the villages of rural China, India, Indonesia and Africa, where it might be needed most.




As the planet changes, one species may have the social skills to survive.I'm talking about... ants.


Mark Moffett is one of the most colorful bug specialists on the planet.His adventures are legion, and yes, Moffett has appeared on the Colbert Report, as well as an obscure publication, called the National Geographic.


Mark got his Harvard Ph.D. from the Dean of ants, famed conservationist Edward O. Wilson.He's currently a Research Associate in Entomology, at the Smithsonian Institution.His new book is "Adventures among Ants: A Global Safari with a Cast of Trillions."


We started off with a couple of Mark�s strange adventures, as he tracked bugs around the world.That included a swath of solider ants, capable of taking down and killing large mammals, like himself.


Is it fair to say that ants have civilizations?Yes indeed, says Mark Moffett.He describes the detailed agriculture carried on by ants, including the adoption of edible fungi which can no longer survive outside the ant colonies.They even developed their own pesticides.


One of the problems arising from world trade and travel is invasive species.It turns out that some ants being redistributed on Earth.Mark tells us about the ant war, currently raging in southern California.




All the species of the world will need to adapt to climate change, and other impacts of human civilization.We look at how ants are doing.First of all, how long have ants been on Earth? Well over 100 million years.There were ants during the time of the dinosaurs, but they played a minor role in those times.


It wasn�t until the arrival of the flowering plants that ants began to really flourish on Earth.But at least we know they survived a whole series of extreme climate changes � from multiple hothouse worlds to the ice ages � that killed off many other species.Ants are tough.


Some ants have air conditioning systems for their colonies.They burrow down up to 30 feet in the earth, and then erect structures that work like chimneys, rising up out of the ground.All their inner spots must be kept so that not only the ants, but their crops, survive any weather.


Ants have no lungs.Could they be affected by changes in carbon dioxide levels in the air?


Are there signs of an impact on them already, either in temperature, precipitation changes, or in their food sources?Like most other species, ants are moving either North, toward the cooler poles, or South in the Southern hemisphere.Or, if heat becomes a problem, they may move upward, toward the tops of mountain ranges, displacing other ants or insects.


The extreme precipitation events that accompany climate change can be a big problem for ants.Burrows and ant highways can be washed away, as banks collapse or flood.


I vaguely understand that some insects will multiply much more rapidly with each degree of temperature rise.Mark gives us some startling examples.With more heat, we may see billions or even trillions more pest insects.


But don�t count ants among the pests.Sure there are some that bite, and others you don�t want in your kitchen.But Moffett says the Earth can get along much better without humans, than it could without ants.These little critters clean up a lot of waste vegetation, and add more nutrients and air to soils than worms do.There is a long list of helpful functions that ants perform � for all the creatures, for free.


When I consider the complexity of ant societies - their agriculture, health-care, communications, and all that - I wonder if they might some day replace humans.


We've been talking ants, with Dr. Mark Moffett, the wild man of Entomology.His new book from the University of California Press is "Adventures among Ants: A Global Safari with a Cast of Trillions."It is anything but boring, and makes us reconsider our own civilization.Find out more at: adventuresamongants.com


That�s it for this week � a full show.Our music was �In the Heat of the Night� by Canadian artist Bryan Adams.


Alex Smith