May 11, 2010
Earth Could Be Too Hot For Humans By 2300
Research released Tuesday revealed that climate change could make most of the world too hot for human habitation within just three centuries.
Scientists from Australia's University of New South Wales, along with colleagues from Purdue University in the United States, discovered that rising temperatures in some places could mean humans would be unable to adapt or survive.
"It would begin to occur with global-mean warming of about seven degrees Celsius (13 Fahrenheit), calling the habitability of some regions into question," the researchers said in their paper.
"With 11-12 degrees Celsius warming, such regions would spread to encompass the majority of the human population as currently distributed."
Research professor Steven Sherwood said there was no chance the Earth would heat up seven degrees this century, but there was a serious risk that the continued burning of fossil fuels would create the problem by 2300.
"There's something like a 50/50 chance of that over the long term," he told AFP.
The study looked at the "heat stress" produced by combining the impact of rising temperatures and increased humidity.
Sherwood said climate change research has been "short-sighted" not to probe into the long-term consequences of the impact of greenhouse gases, which cause global warming.
"It needs to be looked at," he told AFP. "There's not much we can do about climate change over the next two decades but there's still a lot we can do about the longer term changes."
Australian National University academics said in a paper published in the Proceedings of the National Academy of Sciences that climate change would not stop in 2100.
"And under realistic scenarios out to 2300, we may be faced with temperature increases of 12 degrees (Celsius) or even more," Professor Tony McMichael told AFP.
"If this happens, our current worries about sea level rise, occasional heatwaves and bushfires, biodiversity loss and agricultural difficulties will pale into insignificance beside a major threat -- as much as half the currently inhabited globe may simply become too hot for people to live there."
Study co-author Matthew Huber of Purdue University said that while the Intergovernmental Panel on Climate Change showed the Earth could rise 7 degrees by 2010, eventual warming over several centuries of 25 degrees is feasible.
The researchers found that humans and most mammals experience potentially lethal levels of heat stress when temperatures rise to above 95 degrees sustained for six hours or more.
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