"There's a shift going on but it's a subtle one. It's underneath, it's not entirely visible but I see it," said Robert Corell, the American head of a large study on Arctic climate change.

The United States has not signed the Kyoto protocol on global warming, but Washington vowed on Monday to work with a group of Arctic nations on proposals to address the impact of climate change on the extreme north region.

"The United States supports a number of the draft policy recommendations and is considering other proposals," the US government said in a statement.

"We support those recommendations that are both consistent with the administration's broader climate change policy, and that are appropriate for the unique attributes of the Arctic Council as a regional forum," it said.

If carbon dioxide emissions are not reduced, the Arctic ice cover will completely disappear in summer within the next 100 years and the region's biodiversity will change dramatically, researchers meeting in Reykjavik warned.

Rising temperatures will cause sea levels to rise, forcing some coastal populations to leave their homes, and could lead to the extinction of some species, such as polar bears which need the ice to access their main prey, seals.

Other species will meanwhile migrate north as temperatures rise.

"If you do not want these things to happen, then you're going to have to change the amount of CO2 and other greenhouse gases in the atmosphere. That is a scientific fact, that's not a policy comment," Corell said.

He said another sign of renewed American interest in global warming was the fact that five senators -- including four Republicans -- travelled to the Arctic Svalbard archipelago last summer to study the effects of climate change.

The US Senate is expected to devote a special session to climate change on November 16, Corell said.

According to a new report published on Monday, even with only "moderate" future emissions of carbon dioxide and other greenhouse gases, average temperatures in the Arctic region could rise by four to seven degrees Celsius (seven to 13 degrees Fahrenheit) by the year 2100.

The Arctic Climate Impact Assessment (ACIA) report was compiled by an international team of 300 researchers.

"Climate change is not something that is going to happen in a far-distant future. It's not something that I won't have to worry about or that my children won't have to worry about but something that all of us should be worried about right now," Samantha Smith of the WWF environmental organisation said.

"It's happening now, it's happening at a speed that we could not have imagined even 10 or 20 years ago... Climate change will not stop at 66 degrees north" at the Arctic Circle, she said.

Indigenous Inuit hunters and Sami reindeer herders have begun complaining that they no longer are in a position to predict climatic changes and how much snow to expect in the short term.

According to one of the estimates used, the Arctic ice could melt away completely in warmer months as early as 2070.

Although the melting of the floating Arctic ice field will not cause sea levels to rise (ice takes more room than water in liquid form), the melting of terrestrial glaciers is expected to push sea levels up by between 10 and 90 centimeters (3.9 to 35.4 inches).

On November 24, the foreign ministers of the eight countries of the Arctic Council -- Canada, Sweden, Russia, Iceland, Denmark, Norway, Finland and the United States -- are scheduled to meet in the Icelandic capital on November 24 to discuss the political ramifications of the ACIA report.

The eight countries are responsible for 30 to 40 percent of the world's carbon dioxide emissions.

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