and the Environmentalist Staff
The ice shelf began its visible collapse on February 28th, when a huge iceberg (41 x 2.5 kilometers - 25.5 by 1.5 miles) broke away, triggering a wider collapse of 405 square kilometers (160 square miles) of the shelf.
Satellite imagery from the National Snow and Ice Data Center at the University of Colorado at Boulder reveals that a 13,680 square kilometer (5,282 square mile) ice shelf has begun to collapse because of rapid climate change in a fast-warming region of Antarctica.
The Wilkins Ice Shelf is a broad plate of permanent floating ice on the southwest Antarctic Peninsula, about 1,000 miles south of South America. In the past 50 years, the western Antarctic Peninsula has experienced the biggest temperature increase on Earth, rising by 0.5 degree Celsius (0.9 degree Fahrenheit) per decade. NSIDC Lead Scientist Ted Scambos, who first spotted the disintegration in March, said, "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 break-up."
The edge of the shelf crumbled into the sky-blue pattern of exposed deep glacial ice that has become characteristic of climate-induced ice shelf break-ups such as the Larsen B in 2002. A narrow beam of intact ice, just 6 kilometers wide (3.7 miles) was protecting the remaining shelf from further breakup as of March 23.
Scientists have tracked this with great interest, both for the indications of warming, the loss of habitat and the concern that other ice shelves, similarly impacted, do have the potential to significantly raise sea level. NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and data from ICESat alerted scientists to the ice shelf's collapse in mid-March.
"The Wilkins disintegration won't raise sea level because it already floats in the ocean, and few glaciers flow into it." Scambos said. "However, the collapse underscores that the Wilkins region has experienced an intense melt season. Regional sea ice has all but vanished, leaving the ice shelf exposed to the action of waves."
BAS glaciologist David Vaughan said of the ice shelf, which is supported by a single strip of ice strung between two islands, "Wilkins is the largest ice shelf on West Antarctica yet to be threatened. This [rest of the] shelf is hanging by a thread."
A copy of the NSIDC report is here. The British Antarctic Survey's press release is here. More on another ice shelf collapse (Larson) available here.
Photo Credit (1): National Snow and Ice Data Center; Photo Credit(2): National Snow and Ice Data Center/NASA
Animation Credit (3): National Snow and Ice Data Center; Photo Credit(4): National Snow and Ice Data Center/courtesy Cheng-Chien Liu, National Cheng Kung University (NCKU), Taiwan and Taiwan's National Space Organization (NSPO); processed at Earth Dynamic System Research Center at NCKU, Taiwan.
LABELS: AUSTIN AMERICAN STATESMEN, CHICAGO SUN-TIMES, CLIMATE CHANGE, ENVIRONMENT, GLOBAL WARMING, NASA, NSIDC, REUTERS, USA TODAY