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Some Antarctic Glaciers Shrinking

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AP
The first comprehensive survey of glaciers on the Antarctic Peninsula has shown that the rivers of ice are shrinking, mostly because of warming of the local climate.

It is unclear, however, whether the increased temperature causing the shrinkage is a natural regional effect or a result of global warming, said the scientists who conducted the study, published this week in the journal Science.

Researchers from the British Antarctic Survey and the U.S. Geological Survey analyzed more than 2,000 aerial photographs dating from 1940 and more than 100 satellite images from the 1960s onwards.

They calculated that 87 percent of the 244 glaciers going out to sea from the peninsula have retreated during the last 50 years and that the pace of shrinkage has accelerated in the last decade. Until now, scientists were uncertain whether the glaciers were growing or melting.

"Fifty years ago, most of the glaciers we look at were slowly growing in length but since then this pattern has reversed. In the last five years the majority were actually shrinking rapidly," said the study's leader, Alison Cook of the British Antarctic Survey.

"However, 32 glaciers go against the trend and are showing minor advance. Had we not studied such a large number of glaciers we may have missed the overall pattern."

The Antarctic peninsula is a small segment of the Antarctic continent, located at the South Pole, and the behavior of the ice on the peninsula is not necessarily a reflection of what's going on elsewhere in Antarctica, said another investigator, David Vaughan of the British Antarctic Survey.