Tuesday, January 01, 2008
Climate change and human susceptibility to temperature
In an earlier post this morning, I mentioned that the mainstream media emphasizes excess deaths from heat over those from cold. The topic is discussed at some length in Bjorn Lomborg's Cool It: The Skeptical Environmentalist's Guide to Global Warming
The IPCC finds that the trends we have seen over the twentieth century will continue, with temperatures increasing more over land, more in the winter, and especially in the high northern latitutdes: Siberia, Canada, and the Arctic. In the wintertime, temperatures might increase 9 degrees F in Siberia compared to perhaps 5 degrees F in Africa. There will be an increase in heat waves and a decrease in cold spells. We will see a marked decrease in frost days almost everywhere in the middle and high latitutdes, and this will lead to a comparable increase in the growing-season length.
Models show that heat events we now see every twenty years will become much more frequent. By the end of the century, we will have such events every three years. This confirms the prospect that we could be seeing many more heat deaths -- a tragedy that will indeed be caused by global warming.
But cold spells will decrease just as much as heat waves increase. In areas where there is one cold spell everey three years, by the end of the century such spells will happen only once every twenty years. This means fewer deaths from cold, something we rarely hear about.
In the U.S. 2005 Climate Change and Human Health Impacts report, heat is mentioned fifty-four times and cold just once. It might seem callous to weigh lives saved versus those lost, but if our goal is to improve the lot of humanity, then it's important ot know just how many more heat deaths we can expect compared to how many fewer cold deaths.
For almost every location in the world, there is an "optimal" temperature at which deaths are the lowest. On either side of this temperature -- both when it gets cold and warmer -- death rates increase. However, what the optimal temperature is is a different issue. If you live in Helsinki, your optimal temperature is about 59 degree F; whereas in Athens you do best at 75 degrees F. The important point to notice is that the best temperature is typically very similar to the average summer temperature. Thus, the actual temperature will only rarely go above the optimal temperature, but very often it will be below. In Helsinki, the optimal temperature is typically exceeded only 18 days per year, whereas it is below that temperature a full 312 degrees. Research shows that although 55 extra people die each year from it being too hot in Helsinki, some 1,655 people die from it being too cold.
It may not be so surprising that cold kills in Finland, but the same holds true in Athens. Even though absolute temperatures are of course much higher in Athens than in Helsinki, temperatures still run higher than the optimum one only 63 days per year, whereas 251 days are below it. Again, the death toll from excess heat in Athens is 1,376 people each year, whereas the death toll from excess cold is 7,852.
This trail of statistics leads us to two conclusions. First, we are very adaptable creatures. We live well both at 59 degrees F and 75 degrees F. We can adapt to both cold and heat. Further adaptation on account of global warming will not be unproblematic, because we have already invested heavily in housing and infrustructure such as heating and air conditioning to handle our current climate. But that is why the second point is so important. It seems reasonable to conclude from the data that, within reasonable limits, global warming might actually result in lower death rates.
Death in Europe
The heat wave in Europe in early August 2003 was exceptional in many ways. It was a catastrophe of heartbreaking proportions. With more than 3,500 dead in Paris alone, France suffered nearly 15,000 fatalities from the heat wave. Another 7,000 died in Germany, 8,000 in Spain and Italy, and 2,000 in the United Kingdom; the total death toll ran to more than 35,000. Understandably, this event has become a psychologically powerful metaphor for the frightening vision of a warmer future and our immediate need to prevent it.
The green group Earth Policy Institute, which first totaled the deaths, tells us that as "awareness of the scale of this tragedy spreads, it is likely to generate pressure to reduce carbon emissions. For many of the millions who suffered through these record heat waves and the relatives of the tens of thousands who died, cutting carbon emissions is becoming a pressing personal issue."
Such reports fueled the public perception that the heat wave became a sure indicator of global warming. A recent academic paper has checked this theory and concluded that although the circumstances were unusual, equal or more unusual warm anomolies have occurred regularly since 1979.
Moreover, while thirty-five thousand dead is terrifyingly large number, all deaths should in principle be treated with equal concern. Yet this is not happening. When two thousand people died from heat in the United Kingdom, it produced a public outcry that is still heart. However, the BBC recently ran a very quiet story telling us that deaths caused by cold weather in England and Wales for the past years have hovered around twenty-five thousand each winter, casually adding that hte winters of 1998-2000 saw about forty-seven thousand cold deaths each year. The story then goes on to discuss how the government should make more winter fuel available and how the majority of deaths are caused by strokes and heart attacks.
It is remarkable that a single heat-death episode of thirty-five thousand from many countries can get everyone up in arms whereas cold deaths of twenty-five thousand to fifty thousand a year in just a single country pass almost unnoticed. Of course, we want to help avoid another two thousand dying from heat in the United Kingdom. But presumably we also want to avoid many more dying from cold.
In Europe as a whole, about two hundred thousand people die from excess heat each year. However, about 1.5 million Europeans die annually from excess cold. That is more than seven times the total number of heat death. Just in the past decade, Europe has lost about fifteen million people to the cold, more than four hundred times the iconic heat deaths from 2003. That we so easily neglect these deaths and so easily embrace those caused by global warming tells us of a breakdown in our sense of proportion.
How will heat and cold deaths change over the coming century? Let us for the momment assume -- very unrealistically -- that we will not adapt at all to the future heat. Still, the biggest cold and heat study from Europe concludes that for an increase of 3.6 degrees F, "our data suggest that any increases in mortality due to increased temperatures would be outweighed by much larger short-term declines in cold-related mortalities." For Britain, it is estmated that a 3.6 degrees F increase will mean two thousand more heat deaths but twenty thousand fewer cold deaths. Indeed, a paper trying to incorporate all studies on this issue and apply them to a broad variety of settings both developed and developing around the world found that "global warming may cause a decrease in mortality rates, especially of cardiovascular diseases."
Vent in the comments.
11 Comments:
By 
, at
Tue Jan 01, 06:01:00 PM:
I see heat/cold deaths as a non-issue. You may as well reduce the problem this: "hey, if it get a few degrees warmer, everybody move a few degrees closer to a pole".
I'm a little more concerned with what a few degrees globally does to our weather patterns - primarily with respect to our billion acres of farmland.
I'd also like a more definitive answer on glacial melt. Does an increase of 3.6F put a good portion of metropolitan US underwater? That might be worth averting.
We need insurance against catastrophes. People can adapt to the rest.
By 
Steve M. Galbraith, at
Tue Jan 01, 06:31:00 PM:
We need insurance against catastrophes. People can adapt to the rest.
But how expensive must that insurance be?
IOW, what type of fundamental changes in human activity must be undertaken?
It seems to me that proponents of AGH argue that we need massive changes just to mitigate the more extreme consequences of the warming. We can't tinker here and there.
The difficulty is that this is seemingly an issue where a middle-ground can't be reached. Politics is the art of the possible, the art of compromise; no such work appears possible.
By Peter, at
Tue Jan 01, 07:31:00 PM:
We will not get an honest attempt to deal with the problem, if it is a problem, until Al Gore is coated liberally with hot tar and feathers and swung onto a fence rail for a ride out of town.
A few thousand of the most vociferous glow-ball worming types may need to hang from lamp posts, too, but since they claim that our very existence is the problem, they should be happy.
But as long as they ride their private jets and limosines while demanding that I change my lifestyle, to Hell with them.
By Georg Felis, at
Tue Jan 01, 08:56:00 PM:
In ancient days, the Prophets of Doom would don sackcloth and ashes in order to convince the people of the coming disasters. The relative absence of self-imposed austerity among the modern prophets tends to make us doubt their sincerity. It would be as if one of the ancient prophets were to be found owning a share in the local sackcloth store (i.e. Al Gore and the Carbon Credits of Renown)
By , at
Tue Jan 01, 09:26:00 PM:
Does an increase of 3.6F put a good portion of metropolitan US underwater?
According to the 2007 IPCC report, no, the projected sea level rise (18 - 58 cm) would not place a good portion of the metropolitan US underwater. Wherever did you get such an idea??
We need insurance against catastrophes
Insurance is great when it's a "sure" thing. But if some company were to offer a policy that might repay some of your losses depending on your environmental piousness over many decades, I think I would pass. Especially if the premium were in the tens of trillions dollars and a multitude of unintended consequences.
By , at
Tue Jan 01, 09:40:00 PM:
The area around the North Pole is getting warmer because the ocean currents have changed there. Around the South Pole, things haven't really changed much. The belief in a static climate does seem silly, just ask any volcano.
By , at
Wed Jan 02, 07:47:00 AM:
"For Britain, it is estmated [sic] that a 3.6 degrees F increase will mean two thousand more heat deaths..."
Two words:
Ivory towers.
Maybe it hasn't occurred to this imbecile yet, but heat doesn't kill people. Lack of 'support', such as water, is what kills people. Proof? Two more words:
Las Vegas.
I lived there for a year, and an average day in the summer was easily over 110 degrees. See any mass heat deaths running around the place? No?
Okay, so why doesn't anybody die from heat in Las Vegas, but in Britain, a relatively cool clime, two thousand people are supposed to die because the temperture rises a mere 3.6 degrees?
Ivory towers.
By , at
Wed Jan 02, 01:28:00 PM:
Temperatures that would be no problem for people in one locale can be disasterous for people in a different climate.
This past year during a "cold snap" in Northern Thailand, a tropical area, there was one person that died after lying outside all night in temperatures in the 50's. Of course the massive quantities of alcohol might have played a part.
Numerous Thai people went camping in the North in order to experience the cold. It is a novel experience.
By , at
Wed Jan 02, 07:35:00 PM:
It would be interesting to estimate an equilibrium (cold/heat) "deaths" temperature point.
By , at
Wed Jan 02, 10:07:00 PM:
Surely, "In Helsinki . . . a full 312 days" rather than "degrees?"
By , at
Sun Jan 06, 10:05:00 PM:
Its getting colder in the arctic and antarctic and AL GORE is a liar and so are all those eco-wackos from GREENPEACE
