Warming in the Antarctic was "much more widespread than was thought," while Arctic sea ice wass diminishing and the melting of Greenland's ice cover was accelerating, said the International Polar Year survey.

The frozen and often inaccessible polar regions have long been regarded as some of the most sensitive barometers of environmental change because of their influence on the world's oceans and atmosphere.

Preliminary findings from the on-site survey revealed new evidence that the ocean around the Antarctic has warmed more rapidly than the global average, the World Meteorological Organisation and the International Council for Science said in a joint statement.

Shifts in temperature patterns deep underwater meawhile suggested that the continent's land ice sheet was melting faster.

"These changes are signs that global warming is affecting the Antarctic in ways not previously suspected," the statement added.

"These assessments continue to be refined, but it now appears that both the Greenland and the Antarctic ice sheets are losing mass and thus raising sea level, and that the rate of ice loss from Greenland is growing."

During the survey in 2007 and 2008, special expeditions in the Arctic also found an "unprecedented rate" of floating drift ice, providing "compelling evidence of changes" in the region.

But the focus was on the erosion of land-based ice sheets of Greenland and the Antarctic, which hold the bulk of the world's freshwater reserves.

When the survey began two years ago, they were viewed as largely stable areas despite some worrying signs of fringe melting.

"The message of IPY is loud and clear: what happens in the polar regions affects the rest of the world and concerns us all," the joint statement concluded.

The survey also noted that the melting has the potential to feed more global warming in turn as trapped greenhouse gases could be unleashed from melting permafrost.

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