Newswise — Glaciers in western Antarctica seem to be thinning more rapidly than in the 1990s, and the resulting flow of ice into the Amundsen Sea is contributing to a faster rise in the world's sea level, according to the scientists from the University of Kansas, NASA, and Chile's Center for Scientific Studies.
The report of ice-thickness measurements and other calculations that led to these conclusions appears in the Sept. 23 issue of Science magazine.
A team of KU researchers developed the radar used in the measurement of ice thickness. Surveys were conducted from airplanes flown over western Antarctica in November and December 2002.
Prasad Gogineni, distinguished professor of electrical engineering and computer science; Pannir Kanagaratnam, research assistant professor at the Information and Telecommunication Technology Center; and 16 colleagues note in the article that the glaciers that rim the Amundsen Sea are discharging 60 percent more ice into the sea than they accumulate from snowfall.
About 253 cubic kilometers of ice are moving from the glaciers into the Amundsen Sea each year, the researchers say " a volume equal to about 241,000 Empire State buildings.
"Previous estimates were closer to 150 cubic kilometers a year," Gogineni said.
The larger figure could raise ocean levels worldwide more than .2 millimeters a year. It had been thought that the whole of Antarctica was contributing that much to sea-level rises.
The thinning of glaciers around the Antarctic sea permits ice farther away to move closer and eventually add to sea-level increases, Kanagaratnam says.
Gogineni credited Kanagaratnam, Torry Akins, research associate at ITTC, and KU graduate students for helping in the development of airborne radar that can measure ice-sheet thickness.
This technology helped make the measurement of ice thickness more accurate and, in turn, aided in the detection of the imbalance between snowfall and ice discharge, Gogineni said.
Is the increased glacial thinning the result of global warming?"We can't attribute the thinning of glaciers around the Amundsen Sea to global warming at this stage," Gogineni said. "Ice sheets may still be responding to past climate changes."
Gogineni said he agrees, however, with the conclusion of the U.S. Climate Change Science Program that there are significant human impacts on climate and that warming is taking place.
The Center for Scientific Studies, The Andes Foundation and the Millenium Science Initiative -- all in Chile -- and NASA's Cryospheric Processes Program funded the research. The project was led by NASA's Robert Thomas and Eric Rignot.
Harish Ramamoorthy, a KU graduate research assistant, also contributed to the discovery.
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