Scientists find bigger than expected polar ice melt

Yahoo News 25 Feb 09;

GENEVA (AFP) – Icecaps around the North and South Poles are melting faster and in a more widespread manner than expected, raising the sea level and fuelling climate change, a scientific survey revealed Wednesday.

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.

Study: Antarctic glaciers slipping swiftly seaward
Eliane Engeler, Associated Press Yahoo News 25 Feb 09;

GENEVA – Antarctic glaciers are melting faster than previously thought, which could lead to an unprecedented rise in sea levels, scientists said Wednesday.

A report by thousands of scientists for the 2007-2008 International Polar Year concluded that the western part of the continent is warming up, not just the Antarctic Peninsula.

Previously most of the warming was thought to occur on the narrow stretch pointing toward South America, said Colin Summerhayes, executive director of the Britain-based Scientific Committee on Antarctic Research and a member of International Polar Year's steering committee.

Satellite data and automated weather stations indicate that "the warming we see in the peninsula also extends all the way down to what is called west Antarctica," he told The Associated Press. "That's unusual and unexpected."

During the International Polar Year, thousands of scientists from more than 60 countries engaged in intense Arctic and Antarctic research over the past two southern summer seasons — on the ice, at sea, and via icebreaker, submarine and surveillance satellite.

The biggest western Antarctic glacier, the Pine Island Glacier, is moving 40 percent faster than it was in the 1970s, discharging water and ice more rapidly into the ocean, Summerhayes said.

The Smith Glacier, also in western Antarctica, is moving 83 percent faster than it did in 1992, he said.

All the glaciers in the area together lose a total of around 114 billion tons per year because the discharge is much greater than the new snowfall, Summerhayes said.

"That's equivalent to the current mass loss from the whole of the Greenland ice sheet," he said, adding that the glaciers' discharge was making a significant contribution to the rise in sea levels. "We didn't realize it was moving that fast."

Antarctica's average annual temperature has increased by about 1 degree Fahrenheit since 1957, but is still 50 degrees Fahrenheit below zero, according to a recent study by Eric Steig of the University of Washington.

Summerhayes said the glaciers were slipping into the sea faster because the floating ice shelf that would stop them — usually 656 to 984 feet thick — is melting.

Sea levels will rise faster than predicted by the Intergovernmental Panel on Climate Change, Summerhayes said.

An IPCC panel in 2007 predicted warmer temperatures could raise sea levels by 30 to 50 inches this century, which could flood low-lying areas and force millions to flee.

"If the west Antarctica sheet collapses, then we're looking at a sea level rise of between 1 meter and 1.5 meters (approximately 3 to 5 feet)," Summerhayes said.

The IPY researchers found that the southern ocean around Antarctica has warmed about 0.36 degrees Fahrenheit in the past decade, double the average warming of the rest of the Earth's oceans over the past 30 years, he said.

The warming of western Antarctica is a real concern Summerhayes said. "There's some people who fear that this is the first signs of an incipient collapse of the west Antarctic ice sheet."