A large floating ice mass is seen in the
gateway of the Antarctic Peninsula March 9, 2008. On the Antarctic
Peninsula, which stretches out from Antarctica toward the South Atlantic
Ocean, some of the huge ice shelves that line its coasts have now
disintegrated and are floating in chunks in the ocean. (Xinhua/Reuters
Photo) Photo
Gallery>>>
WASHINGTON, March 25 (Xinhua) -- Imagery taken by
U.S. satellites shows a portion of Antarctica's massive Wilkins Ice Shelf has
begun to collapse because of rapid climate change in a fast-warming region of
the continent, scientists at the U.S. National Snow and Ice Data Center
announced on Tuesday.
While the area of collapse involves 160 square miles
at present, a large part of the 5,000-square-mile Wilkins Ice Shelf is now
supported only by a narrow strip of ice between two islands, said Ted Scambos,
lead scientist at NSIDC.
"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 added.
In the past 50 years, the western Antarctic Peninsula
has experienced the biggest temperature increase on Earth, rising by 0.9 degree
F (0.5 Celsius degree) 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 activity
in March.
The Wilkins Ice Shelf is a broad sheet of permanent
floating ice on the southwest Antarctic Peninsula roughly 1,000 miles south of
South America.
Satellite images indicate the Wilkins began its
collapse on Feb.28. Data revealed that a large iceberg, measuring 25.5 by 1.5
miles (2.4 kilometers), fell away from the ice shelf's southwestern front,
triggering a runaway disintegration of 220 square miles of the shelf interior.
With Antarctica's summer melt season drawing to a
close, scientists do not expect the Wilkins to further disintegrate in the next
several months. "This unusual show is over for this season," Scambos said. "But
come January, we'll be watching to see if the Wilkins continues to fall apart."
The Wilkins is one of a string of ice shelves that have collapsed in the West Antarctic Peninsula in the past 30 years. The Larsen B became the most well-known of these, disappearing in just over 30 days in 2002. The Prince Gustav Channel, Larsen Inlet, Larsen A, Wordie, Muller and Jones ice shelf collapses also underscore the unprecedented warming in this region of Antarctica, said Scambos.
