Greenland's Helheim glacier: a melting mystery
Scientists say the Greenland ice sheet is losing about 7 billion cubic feet of ice a year. Now, they are just finally beginning to uncover some reasons why its been shrinking.
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"We've had a confirmation that the waters are really coming up to the glacier," Stranneo says, her voice nearly drowned by engine noise aboard the Arctic Sunrise, a Greenpeace ship that offered her a chance to test her hypothesis. "This is the first time that we've seen it in these southeast glacial fjords."Skip to next paragraph
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In July, the world's oceans were the warmest in almost 130 years of record-keeping. Meteorologists say a combination of factors are at work, including a natural El Nino system, man-made global warming and a dash of random weather.
Coinciding with the shrinking of sea ice on the North Pole and the thawing of the Arctic permafrost, the discovery of Greenland's runaway glaciers earlier this decade raised a sense of urgency among scientists studying the impact of climate change on the frozen north.
It has also been used by advocacy groups like Greenpeace to stress the importance of reaching a deal in Copenhagen to limit global greenhouse emissions.
The UN's top climate official, Yvo de Boer, said Friday that negotiations on fighting climate change are moving so slowly that it will be impossible to reach a comprehensive deal by December. He said the Copenhagen meeting should aim instead to agree on "key cornerstones" of emissions cuts and how to finance them.
The 2007 report by the Intergovernmental Panel on Climate Change projects a sea level rise of 7 to 24 inches (20 to 60 centimeters) this century. Adding the potential impact of ice sheets in Greenland and Antarctica, many scientists have estimated the rise will be double.
"It doesn't sound like a lot, but it's an important difference by the way you sort of deal with that issue," says Hamilton, taking a break from his GPS measurements on a plateau overlooking Helheim's styrofoam-like bed of jagged ice. "How you engineer for a sea level rise of 30 centimeters is quite different as to how you would ... deal with a sea level rise of 1 meter."
His latest measurements indicate that Helheim is flowing at 6.5 miles per year, slightly down from its peak in 2005 but still 50 percent faster than its normal pace.
Other researchers say some — but not all — of Greenland's glaciers have shown similar slowdowns in recent years, suggesting that a sudden, dramatic increase in flow speeds may not be such a cataclysmic and irregular phenomenon after all.
Still, the flows remain fast enough to yield a net loss of mass from the ice sheet. And if the world continues to warm, sudden spurts of glacial acceleration may become more frequent, draining the inland ice until it, eventually, collapses.
No one can say with certainty whether that will take 100 years, or 1,000.
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