Greenland Icecap
Thickens Slightly Despite Warming
October 21, 2005 — By Reuters
OSLO — Greenland's ice-cap has
thickened slightly in recent years despite wide predictions of a thaw
triggered by global warming, a team of scientists said on Thursday.
The 3,000-metre (9,842-feet) thick ice-cap is a key concern in debates
about climate change because a total melt would raise world sea levels
by about 7 metres. And a runaway thaw might slow the Gulf Stream that
keeps the North Atlantic region warm.
But satellite measurements showed that more snowfall was falling and
thickening the ice-cap, especially at high altitudes, according to the
report in the journal Science.
Glaciers at sea level have been retreating fast because of a warming
climate, making many other scientists believe the entire ice-cap was
thinning.
"The overall ice thickness changes are ... approximately plus 5 cms (1.9
inches) a year or 54 cms (21.26 inches) over 11 years," according to the
experts at Norwegian, Russian and U.S. institutes led by Ola Johannessen
at the Mohn Sverdrup centre for Global Ocean Studies and Operational
Oceanography in Norway.
However, they said that the thickening seemed consistent with theories
of global warming, blamed by most experts on a build-up of heat-trapping
gases from burning fossil fuels in power plants, factories and cars.
Warmer air, even if it is still below freezing, can carry more moisture.
That extra moisture falls as snow below 0 Celsius (32.00F).
And the scientists said that the thickening of the ice-cap might be
offset by a melting of glaciers around the fringes of Greenland.
Satellite data was not good enough to measure the melt nearer sea level.
ICE SHEETS
Most models of global warming indicate that the Greenland ice might melt
within thousands of years if warming continues.
Oceans would rise by about 70 metres if the far bigger ice-cap on
Antarctica melted along with Greenland. Antarctica's vast size acts as a
deep freeze likely to slow any melt of the southern continent.
The panel that advises the United Nations has predicted that global sea
levels might rise by almost a metre by 2100 because of a warming
climate.
Such a rise would swamp low-lying Pacific islands and warming could
trigger more hurricanes, droughts, spread deserts and drive thousands of
species to extinction.
Still, a separate study in Science on Thursday said sea levels were
probably rising slightly because of a melt of ice sheets.
"Ice sheets now appear to be contributing modestly to sea level rise
because warming has increased mass loss from coastal areas more than
warming has increased mass gain from enhanced snowfall in cold central
regions," it said.
"Greenland presently makes the largest contribution to sea level rise,"
according to the report by scientists led by Richard Alley of
Pennsylvania State University in the United States.
Source: Reuters |