USGS Documents Melting of Antarctic Ice Shelves

Antarctica’s glaciers are melting more rapidly than previously known because of climate change, according to a new U.S. Geological Survey report prepared in close collaboration with the British Antarctic Survey.

The USGS study documents for the first time that one ice shelf has completely disappeared and another has lost a chunk three times the size of Rhode Island.

The USGS study focuses on Antarctica, which is the Earth’s largest reservoir of glacial ice. In a separate study published in Geophysical Letters, the National Oceanic and Atmospheric Administration reports that ice is melting much more rapidly than expected in the Arctic as well, based on new computer analyses and recent ice measurements.

Using historical and recent satellite imagery, aerial photography, and other data, as well as the newest mapping techniques, the USGS study maps recent glacier retreat along Antarctica’s Larsen and Wordie Ice Shelves. It represents just one map of several upcoming studies of Antarctica's glaciers.

Scientists previously knew that the Wordie Ice Shelf had been retreating, but this study documents for the first time that it has completely disappeared. Moreover, the northern part of the Larsen Ice Shelf no longer exists. An area more than three times the size of Rhode Island (more than 8,500 km2) has broken off from the Larsen Ice Shelf since 1986.

“This continued and often significant glacier retreat is a wakeup call that change is happening in our Earth System and we need to be prepared,” said USGS glaciologist Jane G. Ferrigno, lead author on the study. “Antarctica is of special interest because it holds an estimated 91 percent of the Earth’s glacier volume, and change anywhere in the ice sheet poses significant hazards to society.”

To view the report, “Coastal-Change and Glaciological Map of the Larsen Ice Shelf Area, Antarctica: 1940-2005” and its accompanying map, visit http://pubs.usgs.gov/imap/2600/B.

The other completed reports in the Coastal Change and Glaciological Maps of Antarctica series can be viewed at http://pubs.usgs.gov/imap/2600.

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