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Published on March 27, 2008

Antarctica's massive Wilkins Ice Shelf has started disintegrating under the effect of global warming, satellite images by University of Colorado's National Snow and Ice Data Centre showed.

The collapse of a substantial section of the shelf was triggered on February 28 when an iceberg measuring 41 by 2.4 kilometres broke off its southwestern front. That movement led to disintegration of the shelf's interior, of which 414 square kilometres have already disappeared, scientists said.

The Wilkins Ice Shelf is a broad plate of permanent floating ice 1,609km south of South America, on the southwest Antarctic Peninsula.

Now, as a result of recent losses, a large part of the 12,950-square-kilometre shelf is supported by a narrow 5.6km strip of ice between two islands, scientists said.

"If there is a little bit more retreat, this last 'ice buttress' could collapse and we'd likely lose about half the total ice shelf area in the next few years," NSIDC lead scientist Ted Scambos said.

"Wilkins is the largest ice shelf on West Antarctica yet to be threatened. This shelf is hanging by a thread," David Vaughan of the British Antarctic Survey said.

Jim Elliott, who was onboard a British Antarctic Survey aircraft sent to video the damage, said the scene looked like a bomb site.

"I've never seen anything like this before - it was awesome," he said. "We flew along the main crack and observed the sheer scale of movement from the breakage. Big hefty chunks of ice, the size of small houses, look as though they've been thrown around like rubble - it's like an explosion."

"Climate warming in the Antarctic Peninsula has pushed the limit of viability for ice shelves further south, setting some of them that used to be stable on a course of retreat and eventual loss," Vaughan said.

Vaughan said the Wilkins breakout would not affect sea levels because it was already floating when it broke off.

With the Antarctic summer drawing to a close, scientists do not expect the ice shelf to further disintegrate in the next several months.

AFP, Washington

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Shattering shelves

>> Larsen A Ice Shelf, spanning 75 by 35 kilometres, disintegrated in 1995.

>> Larsen B, which had a surface area of 3,850 square kilometres collapsed in 2002.

>> Calculations show sea levels could rise 1.4 metres by the end of the century.