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Antarctic glaciers decayed by rain

MORE rain on the Antarctic Peninsula is speeding a melt of glaciers such as the Sheldon, which has retreated 2 kilometers in 20 years and is nudging up world sea levels, a leading expert said.

"Rain is very corrosive to glaciers and at least in part the reason this glacier is retreating," David Vaughan, a British Antarctic Survey glaciologist, said on an inflatable speedboat in a bay that had been blanketed by ice for thousands of years.

"The glacier has retreated since 1989 and left this open water. That's the same pattern for 87 percent of 400 glaciers along the Antarctic Peninsula," he told Reuters.

The ice cracks and growls as the 70-meter-high ice cliffs at the front of the Sheldon glacier slide downhill, some of the ice a bluish white.

The front edge of the Sheldon -- a small glacier by Antarctic standards -- has receded 2 kilometers since 1989, apparently because of global warming blamed on greenhouse gases emitted by burning fossil fuels, Vaughan said.

Temperatures were above freezing with clear skies for the past two days. Rain spattered the glacier on Wednesday and has fallen several times this month.

Vaughan said rain was becoming more frequent in summertime on the peninsula, the northernmost part of Antarctica that sticks up toward South America. The peninsula is warming faster than anywhere else in the southern hemisphere.

The thaw of Sheldon, near the British Rothera research station and other peninsula glaciers, is part of a wider melt adding to world sea levels.

"It doesn't add up to much on its own but by the time we've added Patagonia, Alaska, all those other areas where glaciers are receding, we have 1 millimeter at least (a year) of sea level rise around the globe," Vaughan said.

Adding in other factors including that water expands as it warms up, ocean levels are rising 3 milimeters a year. And the rate is accelerating, after a gain of 17 centimeters during the 20th century.

Vaughan, a leading member of the UN Climate Panel, said there were worrying signs that vast glaciers to the south were also starting to spill more water into the sea.

"The concern is ... that the much bigger glaciers (further south) are going to start doing the same thing," he said.


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