Beware of Rapidly Melting Glaciers this Century
Pastor Dale Morgan
Beware of Rapidly Melting Glaciers this Century*
From correspondents in Washington
July 20, 2007 05:06am
Article from: Reuters
DON'T worry too much, for now, about rising seas caused by melting ice
in Greenland and Antarctica. The big threat this century could come from
small thawing glaciers, researchers reported overnight.
Even though these glaciers contain only 1 per cent of the water tied up
in the great ice sheets of Antarctica and Greenland, they could account
for 60 per cent of an anticipated rise in the world's sea level by the
year 2100.
Sea-level rise is seen a key consequence of global warming, and much of
the concern has focused on the big ice sheets that contain the vast
majority of the world's ice.
Researchers writing in the online journal Science Express estimate
melting glaciers, which are located all over the globe including in the
tropics, could add between 10 and 25 centimetres to world sea level this
century.
While this may not sound like much, consider that some 100 million
people live within 1 vertical metre of sea level, said Mark Meier of the
University of Colorado-Boulder, a lead author of the study.
"If we had almost a foot (of sea-level rise) just due to the small
glaciers, add that to the amount due to the ice sheets, which could be
appreciable by 2100, and add to that the ocean warming which will cause
it to expand in volume, then we get a rise that we can't ignore," Mr
Meier said.
Even a tiny amount of sea-level rise can make a vast inland incursion of
water in flat coastal areas, as much or more than 100 times the distance
inland as the height of the rise, he said.
Mr Meier said the huge amounts of ice locked in Greenland and Antarctica
hold the potential for "some really horrendous sea level rise" - as much
as 1 metre - if they ever completely melt.
That is unlikely to happen this century, although Greenland's ice sheet
currently contributes 28 per cent and Antarctica's contributes 12 per
cent to the total ice-melt that fuels sea-level rise, the researchers found.
"Now don't ask me about 1,000 years from now," Mr Meier said.
"But for the next few generations we think that we should not ignore the
little glaciers."
There are hundreds of thousands of small glaciers all over the world,
including in tropical New Guinea, but the important ones in terms of
global sea-level change are in Alaska, Canada, Russia and Scandinavia,
Mr Meier said.
Part of the reason glaciers are contributing more to rising seas is
because of rapid changes in how they flow, co-author Robert Anderson said.
Many glaciers are getting thinner and that makes them slide more quickly
toward the sea.