Global warming is melting the Arctic ice faster than expected, and the world's oceans could rise by about a metre (3 feet) by 2100, swamping homes from Bangladesh to Florida, the head of a study said on Tuesday. Robert Corell, chairman of the eight-nation Arctic Climate Impact Assessment (ACIA), also told a news conference there were some hints of greater willingness by the United States, the world's top polluter, to take firmer action to slow climate change.
Speaking at the start of a four-day scientific conference in Reykjavik, Corell said global warming was melting the Greenland ice sheet and Arctic glaciers from Alaska to Norway quicker than previously thought.
"Greenland will play a much bigger role in sea level rise than anticipated," said Corell, a scientist at the American Meteorological Society.
He said a 2001 UN report forecast world ocean levels would rise by 20-90 cms by 2100. He said some UN forecasts assumed melting Greenland ice would cause just 4 mm of the rise.
"We'll be at the top of the range, about a metre," he said. The ACIA report says that Greenland's melt alone could add 10 cms to global sea levels by 2100. Melting of other Arctic glaciers would also contribute.
About 17 million people in Bangladesh live less than one metre above sea level. Pacific islands like Tuvalu could be swamped and much of Florida south of Miami would be inundated by a one metre rise.
Much of the rise projected by UN surveys in the years to 2100 is because water in the oceans expands as it warms, and so is not directly connected to melting ice.
At the other end of the globe from the Arctic, the thicker Antarctic ice is expected to stay more stable, like a deep freeze
The ACIA report was funded by Arctic nations the United States, Canada, Russia, Iceland, Norway, Sweden, Denmark and Finland and is the biggest survey to date of the Arctic climate, by 250 scientists.
It says Arctic temperatures are rising by twice the global average and are set to rise by a further 4-7 Celsius (7-13 Fahrenheit) by 2100.
The report says the melt will threaten the cultures of indigenous peoples and could drive species like polar bears towards extinction as sea ice recedes.
The Arctic heats more rapidly than the global average because dark water, earth and rock, once exposed, soak up more heat than reflective snow and ice.
The eight Arctic governments are due to meet in Iceland on November 24 to decide what to do. Diplomats say they are deadlocked, with Washington the most strongly opposed to radical action.
"There are mixed signals in the United States," Corell said of Washington's attitude towards tackling global warming. But "I think that there is a shift going on."
He said that some Republican senators, for instance, had asked him for personal briefings about the climate report.
Senator John McCain, a Republican who has co-operated with Democrats on global warming, is optimistic about passing a bill in coming years to cap US greenhouse gas emissions, he said.
President George W. Bush pulled out in 2001 of the UN's Kyoto protocol, a first step towards limiting emissions of gases like carbon dioxide from fossil fuels in cars, factories and power plants. Bush argues that Kyoto was too costly and wrongly excluded developing nations.