Melting Antarctic Ice Causing Sea Levels to Rise
By Armando Duke
Houston, TX - Satellite surveys show that ice is melting in
Antarctica faster than snowfall can replenish it, which is
causing sea levels to rise.
Two separate studies showed varying results. But both studies
drew the same conclusion that the ice in Antarctica is melting
rapidly. The only difference between the two studies was the
degree that sea levels were rising.
The authors work in both studies added weight to the evidence
that global warming was affecting sea levels.
Earlier estimates were that global warming was causing an
increase in rainfall that would generate more snow in Greenland
and the Antarctic, replacing the ice that was grumbling into
the sea.
"Snowfall will matter less and less," said Robert Bindschadler,
an expert on polar ice at the National Aeronautics and Space
Administration. Bindschadler was not involved in either study.
Satellite images show that most of the ice is being lost in
western Antarctica, where warming air and seawater have recently
broken up huge floating shelves of ice.
A survey led by H. Jay Zwally, a NASA scientist, used satellites
and aircraft to measure changes in the height of ice sheets
in Antarctica and Greenland over the decade ended in 2002.
A second study by scientists at the University of Colorado
looked at changes from 2002 to 2005 using a pair of NASA
satellites that detect subtle changes in Earth's gravitational
field that can be used to estimate the weight of water in an
ice sheet.
Zwally's study found a loss of volume in Antarctica and a
small overall gain in Greenland, where inland snows have
outpaced ice flowing into the sea. Zwally published his
findings in the Journal of Glaciology.
Scientists at the University of Colorado found that changes
in the ice were a good indicator of the changing climatic
conditions there. Their study was published in the Journal
of Science.
The National Oceanic and Atmospheric Administration said the
Colorado team's estimate of 35 cubic miles of ice being lost
annually in Antarctica fit well with current ideas about
what was causing the rise in sea level.
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