Oceans May Rise up to 140 cms by 2100 Due to Warming

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http://www.planetark.com/dailynewsstory.cfm/newsid/39504/story.htm



Oceans May Rise up to 140 cms by 2100 Due to Warming
NORWAY: December 15, 2006


OSLO - The world's oceans may rise up to 140 cms (4 ft 7 in) by 2100 due to global warming, a faster than expected increase that could threaten low-lying coasts from Florida to Bangladesh, a researcher said on Thursday.


"The possibility of a faster sea level rise needs to be considered when planning adaptation measures such as coastal defences," Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research wrote in the journal Science.
His study, based on air temperatures and past sea level changes rather than computer models, suggested seas could rise by 50-140 cms by 2100, well above the 9-88 cms projected by the scientific panel that advises the United Nations.

A rise of one metre might swamp low-lying Pacific islands such as Tuvalu, flood large areas of Bangladesh or Florida and threaten cities from New York to Buenos Aires.

"The computer models underestimate the sea level rise that has already occurred," Rahmstorf told Reuters of a rise of about 20 cms since 1900. "There are aspects of the physics we don't understand very well."

Sea level changes hinge on poorly understood factors such as the pace of the melt of glaciers and of ice sheets in Greenland and Antarctica. Water also expands as it gets warmer but the rate of penetration of heat to the depths is uncertain.

"My main conclusion is not that my forecast is better but that the uncertainty is much larger because of the different results you get with reasonable methods," he said.

Almost all climate scientists reckon the world is warming because of emissions of greenhouse gases from human use of fossil fuels in factories, power plants and cars. Rising temperatures could bring more droughts, floods and heatwaves.