Ice Sheet Shrinking Fast
21 October, 2006
WASHINGTON - The vast sheet
of ice that covers Greenland is shrinking fast, but still not as fast
as previous research indicated, NASA scientists said on Thursday.
Greenland's low coastal regions lost 155 gigatons (41 cubic miles) of
ice each year between 2003 and 2005 from excess melting and icebergs,
the scientists said in a statement.
The high-elevation interior gained 54 gigatons (14 cubic miles) annually
from excess snowfall, they said.
This is a change from the
1990s, when ice gains approximately equaled losses, said Scott Luthcke
of NASA's Planetary Geodynamics Laboratory outside Washington.
"That situation has
now changed significantly, with an annual net loss of ice equal to nearly
six years of average water flow from the Colorado River," Luthcke
Luthcke and his team reported
their findings in Science Express, the advance edition of the journal
The ice mass loss in this
study is less than half that reported in other recent research, NASA
said in a statement, but it still shows that Greenland is losing 20
percent more mass than it gets in new snowfall each year.
The Greenland ice sheet is
considered an early indicator of the consequences of global warming,
so even a slower ice melt there raises concerns.
"This is a very large
change in a very short time," said Jay Zwally, a co-author of the
study. "In the 1990s, the ice sheet was growing inland and shrinking
significantly at the edges, which is what climate models predicted as
a result of global warming.
"Now the processes of
mass loss are clearly beginning to dominate the inland growth, and we
are only in the early stages of the climate warming predicted for this
century," Zwally said.
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