Global warming could eventually make half the Earth's population centers too hot to handle

  • May 5, 2010
  • Science Highlights

A study looking at global warming in terms of heat stress on humans, which also has application to other mammals, like pets and livestock, says half the world’s population centers could become dangerously hot within the next few centuries if the warming trend continues.

The study, published in the Proceedings of the National Academy of Sciences, says the so-called “wet-bulb temperature,” an index factoring in heat and humidity, could begin exceeding 35 degrees Celsius, 95 degrees Fahrenheit, for extended periods. The 35-degree threshold is the point at which the ambient temperature tends to induce “hyperthermia”—overheating—in humans and other mammals.

Even with modest warming, this could expose large fractions of the population to unprecedented heat stress and with severe warming it would become intolerable, potentially dwarfing other impacts from global warming, the study concludes. The results stem from climate simulations done by Purdue Professor Matthew Huber on supercomputers operated by ITaP.

“It changes the nature of the game,” Huber, an earth and atmospheric sciences professor, says of the study he did with colleague Steve Sherwood at the University of New South Wales in Australia. “We’re playing a different game than people have assumed. Most people think we’re playing a game of roulette with unfortunate but not catastrophic impacts if we are unlucky. Our study indicates that the risks involved are more akin to Russian roulette and we don’t know how many chambers have rounds in them.”


Writer: Greg Kline, Information Technology at Purdue (ITaP), 765-494-8167,

Originally posted: May 5, 2010