OSLO - Global warming is heating the Arctic almost twice as fast as the rest of the planet in a thaw that threatens millions of livelihoods and could wipe out polar bears by 2100, an eight-nation report said on Monday.

The biggest survey to date of the Arctic climate, by 250 scientists, said the accelerating melt could be a foretaste of wider disruptions from a build-up of human emissions of heat-trapping gases in the earth's atmosphere.

The "Arctic climate is now warming rapidly and much larger changes are projected," according to the Arctic Climate Impact Assessment (ACIA), funded by the United States, Canada, Russia, Denmark, Iceland, Sweden, Norway and Finland.

Arctic temperatures are rising at almost twice the global average and could leap 4-7 Celsius (7-13 Fahrenheit) by 2100, roughly twice the global average projected by U.N. reports. Siberia and Alaska have already warmed by 2-3 C since the 1950s.

Possible benefits like more productive fisheries, easier access to oil and gas deposits or trans-Arctic shipping routes would be outweighed by threats to indigenous peoples and the habitats of animals and plants.

Sea ice around the North Pole, for instance, could almost disappear in summer by the end of the century. The extent of the ice has already shrunk by 15 percent to 20 percent in the past 30 years.

"Polar bears are unlikely to survive as a species if there is an almost complete loss of summer sea-ice cover," the report said. On land, creatures like lemmings, caribou, reindeer and snowy owls are being squeezed north into a narrower range.

FOSSIL FUELS BLAMED

The report mainly blames the melt on gases from fossil fuels burned in cars, factories and power plants. The Arctic warms faster than the global average because dark ground and water, once exposed, traps more heat than reflective snow and ice.

Klaus Toepfer, head of the U.N. Environment Program, said the Arctic changes were an early warning. "What happens there is of concern for everyone because Arctic warming and its consequences have worldwide implications," he said.

And the melting of glaciers is expected to raise world sea levels by about 10 cm (4 inches) by the end of the century.

Many of the 4 million people in the Arctic are already suffering. Buildings from Russia to Canada have collapsed because of subsidence linked to thawing permafrost that also destabilizes oil pipelines, roads and airports.

Indigenous hunters are falling through thinning ice and say that prey from seals to whales is harder to find. Rising levels of ultra-violet radiation may cause cancers.

Changes under way in the Arctic "present serious challenges to human health and food security, and possibly even (to) the survival of some cultures," the report says.

Farming could benefit in some areas, while more productive forests are moving north on to former tundra. "There are not just negative consequences, there will be new opportunities too," said Paal Prestrud, vice-chair of ACIA.

Scientists will meet in Iceland this week to discuss the report. Foreign ministers from Arctic nations are due to meet in Iceland on Nov. 24 but diplomats say they are deeply split with Washington least willing to make drastic action.

President Bush pulled the United States, the world's top polluter, out of the 126-nation Kyoto protocol in 2001, arguing its curbs on greenhouse gas emissions were too costly and unfairly excluded developing nations.

"Kyoto is only a first step," said Norwegian Environment Minister Knut Hareide, a strong backer of Kyoto. "The clear message from this report is that Kyoto is not enough. We must reduce emissions much more in coming decades."

© Copyright 2004 Reuters Ltd

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