COPENHAGEN, Aug 21 (AFP) Aug 21, 2006
Greenland's glaciers have been shrinking for the past century, according to a Danish study published on Monday, suggesting that the ice melt is not a recent phenomenon caused by global warming.
Danish researchers from Aarhus University studied glaciers on Disko island, in western Greenland in the Atlantic, from the end of the 19th century until the present day.
"This study, which covers 247 of 350 glaciers on Disko, is the most comprehensive ever conducted on the movements of Greenland's glaciers," glaciologist Jacob Clement Yde, who carried out the study with Niels Tvis Knudsen, told AFP.
Using maps from the 19th century and current satellite observations, the scientists were able to conclude that "70 percent of the glaciers have been shrinking regularly since the end of the 1880s at a rate of around eight meters per year," Yde said.
"We studied 95 percent of the area covered by glaciers in Disko and everything indicates that our results are also valid for the glaciers along the coasts of the rest of Greenland," he said.
The biggest reduction was observed between 1964 and 1985.
"A three-to-four degree increase of the temperature on Greenland from 1920 to 1930, and the increase recorded since 1995 has sped up the ice melt," he said.
The effect of the rising temperatures in the 1920s and 1930s was "visible dozens of years later, and that of the 1990s will be (visible) in 10 or 20 years," Yde said, adding that he expected Greenland's glaciers to melt even faster in the future.
The shrinking of the glaciers since the 19th century is "the result of the atmosphere's natural warming, following volcanic eruptions for example and greenhouse gases, created by human activities, which have aggravated the situation further," he said.
The study also showed new results on galloping glaciers, the name given to glaciers that surge very quickly for a few years, up to 50 meters a day, before advancing more slowly at a rate of 20 meters per year," he said.
"We have identified, thanks to new analyses of aerials photographs and satellite images, almost four times more galloping glaciers, or 75 compared to just 20 in previous estimates," he said.
The two authors of the study were to present their results on Monday at a conference in Cambridge, England on the impact of global warming on glaciers.
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