Climate change could make half of the world uninhabitable for humans as a rise in temperature makes it too hot to survive, scientists have warned.
By Louise Gray, Environment CorrespondentPublished: 7:30AM BST 12 May 2010
Researchers from the University of New South Wales in Australia and Purdue University in the US said global warming will not stop after 2100, the point where most previous projections have ended.
In fact temperatures may rise by up to 12C (21.6F) within just three centuries making many countries into deserts.
The study, published in the prestigious journal Proceedings of the National Academy of Sciences, said humans will not be able to adapt or survive in such conditions.
Professor Tony McMichael, one of the authors, said if the world continues to pump out greenhouse gases at the current rate it will cause catastrophic warming.
"Under realistic scenarios out to 2300, we may be faced with temperature increases of 12 degrees or even more," he said. "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."
Professor Steven Sherwood, a fellow author, said there was no chance of the Earth reaching such temperatures this century.
But he said there was a good chance temperatures could rise by at least 7C (12.6F) by 2300, that would also make much of the world inhabitable.
"There's something like a 50/50 chance of that over the long term," he said.
Prof Sherwood said climate change research had been "short-sighted" not to probe the long-term consequences of the impact of greenhouse gases blamed for global warming.
"It needs to be looked at," he said. "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."
::The world should shift to a low carbon economy not to stop climate change but to preserve 'human dignity', according to a report from a self-styled "eclectic" group of academics.
The UN process has failed, they argue, and a global approach concentrating on CO2 cuts will never work.
They urge instead the use of carbon tax revenue to develop technologies that can supply clean energy to everyone and provide 'human dignity'.
Their so-called Hartwell Paper is criticised by others who say the UN process has curbed carbon emissions.
The paper is named after Hartwell House, the Buckinghamshire mansion, hotel and spa where the group of 14 academics from Europe, North America and Japan gathered in February to develop their ideas.