- WASHINGTON (Reuters) - A melting Antarctic glacier could lead to the collapse
of the West Antarctic Ice Sheet (WAIS), causing global sea levels to rise
up to 20 feet , researchers said Thursday.
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- Radar images from satellite observations
between 1992 and 1996 of Pine Island glacier in West Antarctica showed
the glacier is shrinking.
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- "It is important because it could
lead to a collapse of the West Antarctic Ice Sheet," said Eric Rignot,
a radar scientist at the Jet Propulsion Laboratory in California, who led
the study. "We are seeing a glacier melt in the heart of Antarctica."
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- Antarctica, the fifth-largest continent,
is almost completely covered with ice. About 90 percent of the world's
glacial ice is in Antarctica.
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- But scientists say this data from remote
and stormy West Antarctica could be the first real evidence that some of
these massive glaciers might actually be rapidly retreating.
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- "The continuing retreat of Pine
Island glacier could be a symptom of the WAIS disintegration," said
Craig Lingle, a glaciologist at the University of Alaska in Fairbanks,
who is familiar with the study.
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- If the WAIS did collapse it would push
sea levels up throughout the world, with regions near sea level experiencing
more flooding and faster erosion, Lingle said.
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- Pine Island glacier is important because
it is really a fast-moving ice stream, taking accumulated snow from the
interior of the WAIS and spitting it into the ocean in the form of ice,
he added.
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- But if the bottom of a glacier melts
at a faster rate than snow collects on the surface, more ice belched into
the ocean causes sea levels to rise, he explained in a telephone interview.
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- "There is no other example of anything
in West Antarctica that is retreating that fast," Lingle said. "This
is the farthest south this phenomena has been observed."
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- In the study, published in the journal
Science, Rignot speculated warmer ocean waters were causing Pine Island's
rapid bottom melting.
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- "This is one of the most sensitive
ice sheets to climatic change. For many, many years we have neglected the
importance of bottom melting," Rignot said in a telephone interview.
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- Richard Alley, a glaciologist at Penn
State University, said if the glacier retreated too far it would allow
too much ice to escape from the WAIS, causing a collapse.
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- "It would make a hole in the side
of the ice sheet and the remaining ice would drain through that hole,"
he added. "This is the disaster scenario."
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- "If world sea levels went up six
meters there would be problems for all coastal areas," Lingle said.
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- Alley agreed the consequences of a WAIS
ice collapse would be severe. But this study only showed the collapse was
possible, not that it would occur, he pointed out in a telephone interview.
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- "We are not saying it will probably
happen but it is possible and if it does it will affect a lot of people,"
he said.
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