Humans Find A Climate Adaptation Strategy, And It Makes The Planet Hotter

Humans have already adopted a technology to adapt to climate change, and while it has already saved lives, it can also make the planet hotter, according to a working paper being developed by the National Bureau of Economic Research.
Air conditioning has prevented more than 3,100 heat-related deaths per year since 1960, said Olivier Deschenes, a University of California Santa Barbara economist who presented an early version of the paper Tuesday at the University of Chicago, and it could do the same for the world. But unless cleaner energy powers the world's air conditioners, their use will aggravate climate change.
"We have this paradox where the solution to the problem creates more of the problem," Deschenes told about 25 scholars with the Energy Policy Institute at Chicago.
"While the greater use of air conditioning is likely to reduce mortality," the paper states, "it will also speed up the rate of climate change as long as fossil fuels continue to be the dominant source of energy."
The paper's authors document "a dramatic change" in the relationship between temperature and mortality in the U.S. over the course of the 20th Century — so dramatic that "in effect, residents of the U.S. adapted in ways that leave them almost completely protected from extreme heat."
The researchers examined three possible causes for the drop in heat-related mortality—including access to health care and access to electricity—but air conditioning stood out:
"Air conditioning made it possible to reduce the stress on people's thermoregulatory systems during periods of extreme heat," the authors write. "Indeed,. the adoption of residential air conditioning explains essentially the entire decline in the relationship between mortality and days with an average temperature exceeding 90 degrees F."
The drop in mortality corresponds to a decrease in cardiovascular and respiratory-related deaths, but not to deaths from infectious diseases, which tend to occur in the U.S. in winter.
The researchers suggest the 20th Century United States is a good model for 21st Century developing countries. Life expectancy in India and Indonesia is roughly equivalent to the number for 1940 America. And those countries have about as much air conditioning the U.S. had then—almost none.
"The goal is to use the U.S. historical experience to draw lessons for adaptation in current day developing countries," the paper states.
"This paper's results suggest that greater use of air conditioning in these countries would significantly reduce mortality rates both today and in the future as the planet warms. As just one measure of the stakes, the typical Indian experiences 33 days annually where the temperature exceeds 90°F and this is projected to increase by as much as 100 days by the end of the century."
If the most dire climate scenarios come to pass, India's mortality rate could increase 17 percent in 17 years, Deschenes said. The authors consider other possible solutions to climate change — mitigation and geoengineering unlikely — and they consider adaptation inevitable. But the solution needn't be air conditioners, as long as people have a way to cool down.
"Any sort of cooling technologies, our evidence suggests, would have not only big effects in the future, but would have big effects right now."