From: Paul Doherty (pauld@exploratorium.edu)
Date: Thu Sep 23 2004 - 14:40:19 PDT
Message-Id: <l0311076bbd78f33946b0@[192.168.112.30]> Date: Thu, 23 Sep 2004 14:40:19 -0700 From: Paul Doherty <pauld@exploratorium.edu> Subject: SCIENTISTS REPORT INCREASED THINNING OF WEST ANTARCTIC GLACIERS
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>Subject: SCIENTISTS REPORT INCREASED THINNING OF WEST ANTARCTIC GLACIERS
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>
>Gretchen Cook-Anderson
>Headquarters, Washington September 23, 2004
>(Phone: 202/358-0836)
>
>Keith Koehler
>Wallops Flight Facility, Va.
>(Phone: 757/824-1579)
>
>RELEASE: 04-312
>
>SCIENTISTS REPORT INCREASED THINNING OF WEST ANTARCTIC
>GLACIERS
>
> Glaciers in West Antarctica are shrinking at a rate
>substantially higher than observed in the 1990s. They are
>losing 60 percent more ice into the Amundsen Sea than they
>accumulate from inland snowfall.
>
>The study was conducted by a science team from NASA, U.S.
>universities and from the Centro de Estudios CientÌficos in
>Chile. It is based on satellite data and comprehensive
>measurements made in 2002 by a science team aboard a Chilean
>P-3 aircraft equipped with NASA sensors. Science Express
>published the findings today.
>
>The ice loss from the measured glaciers corresponds to an
>annual sea-level rise of .008 inches (.2 millimeters) or more
>than 10 percent of the total global increase of about .07
>inches (1.8 millimeters) per year.
>
>For a balanced glacial system, the amount of glacier ice
>melting or flowing into the sea roughly equals the ice formed
>from snow accumulations further inland. The scientists report
>the Amundsen Sea glaciers are not in balance.
>
>Bob Thomas, a science team member with EG&G Services at the
>NASA Goddard Space Flight Center's Wallops Flight Facility,
>Wallops Island, Va., commented that as the glaciers flow to
>the ocean, they become afloat to form ice shelves. "The ice
>shelves act like a cork and slow down the flow of the
>glacier," Thomas said.
>
>"Ice shelves in the Amundsen Sea appear to be thinning,
>offering less resistance to their tributary glaciers. Our
>measurements show an increase in glacier thinning rates that
>affects not only the mouth of the glacier, but also 60 miles
>(100 kilometers) to 190 miles (300 kilometers) inland,"
>Thomas said.
>
>The scientists noted the earth underneath the ice is further
>below sea level than had been assumed, so the ice is thicker
>than once thought. This increases the amount of ice each
>glacier can discharge into the ocean as its speed increases.
>It makes it easier for the thinning glacier to float free
>from its bed, and thus further 'loosen the cork'," Thomas
>said.
>
>Thomas pointed out the observed increases in velocities and
>thinning rates apply to only a short time period, so it is
>too early to tell if the accelerated thinning is part of a
>natural cycle or is a sign of a longer-term change.
>"Continued observation is important," he said.
>
>"The rates of glacier change remain relatively small at
>present," said Eric Rignot, a study participant from NASA's
>Jet Propulsion Laboratory, Pasadena, Calif. "But the
>potential exists for these glaciers to increase global sea
>level by more than one meter. The time scale over which this
>will take place depends on how much faster the glaciers can
>flow, which we do not know at present," he said.
>
>Thomas said in the last 10 years the ability to accurately
>measure glaciers worldwide has greatly improved. Measurements
>from aircraft and satellites like NASA's Ice, Cloud and Land
>Elevation Satellite (ICESat), launched in 2003, have greatly
>improved accuracy.
>
>To access the study on Science Express, the Web site of the
>journal Science, visit.
>
>http://www.sciencexpress.org
>
>For more information about NASA and agency programs on the
>Internet, visit:
>
>http://www.nasa.gov
>
>
>
>-end-
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