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Ice shelf falling apart
26/03/2008 07:20 - (SA)
Washington - A section of Antarctica's massive Wilkins Ice Shelf has begun disintegrating under the effects of global warming, satellite images by the University of Colorado's National Snow and Ice Data Centre showed.
The collapse of a substantial section of the ice shelf was triggered on February 28 when an iceberg measuring 41 by 2.4km broke off its southwestern front.
That movement led to disintegration of the shelf's interior, of which 414 square kilometres has already disappeared.
As a result, a large part of the 12 950 square kilometre Wilkins Ice Shelf - Antarctica's largest - is now supported by a 5.6km strip of ice between two islands, NSIDC lead scientist Ted Scambos said in a statement.
"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," he said.
Over the past half century, the western Antarctic Peninsula has experienced the biggest temperature increase on Earth, 0.5 degrees Celsius per decade.
"We believe the Wilkins has been in place for at least a few hundred years, but warm air and exposure to ocean waves are causing a breakup," said Scambos, who first spotted the disintegration in March.
With the Antarctic summer drawing to a close, scientist do not expect the ice shelf to further disintegrate in the next several months.
"This unusual show is over for this season," said Scambos. "But come January, we'll be watching to see if the Wilkins continues to fall apart."
Ice shelf breakup in the Antarctic - more than 13 000 square kilometres have been lost over the past 50 years - could significantly increase ocean levels around the world.
According to some calculations based on present sea level rise of three millimetres per year, ocean levels could rise by 1.4m by the end of the century.
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