[CTRL] UNEXPECTED GLACIER MELT MAY DROWN VAST AREAS

[William Shannon]

12/07/00: UNEXPECTED GLACIER MELT MAY DROWN VAST AREAS
Word has just leaked out that the ice sheet that covers Greenland is melting.
This means we could face a rise in sea levels that will flood huge areas in
the world’s most populated regions, according to a report by the United
Nations Intergovernmental Panel on Climate Change (IPCC). Dozens of countries
may be wiped off the map. The Greenland ice sheet contains enough ice and
snow to raise sea levels by over 20 feet if it melts, and looks like that’s
going to happen. The report’s authors are not allowed to discuss their
findings until their report is published next May, but Jonathan Gregory of
Britain’s Hadley Center for Climate Prediction and Research, who co-authored
the chapter on sea levels, said that once the disintegration of the Greenland
ice sheet begins, it will be "irreversible this side of a new ice age." Other
experts quoted in the report predict that the ice sheet could entirely
disappear within 700 years.
If sea levels rise 30 feet by the year 3000, it will cause the inundation of
a total area of the earth larger than the United States, with a population of
more than a billion people and most of the world’s most fertile farmland.
Four years ago, the IPCC predicted that sea levels could rise by 1 ½ feet in
this century and by a maximum of 3 to 10 feet over the next 500 years. Now
they think that a rise of 20 to 40 feet is more likely, which is enough to
drown immense areas of land and many major cities. The new study says that
increase in ocean levels will is inevitable and will occur even if the
governments of the world succeed in stopping global warming within the next
few decades.
At the other end of the globe, recent satellite imagery shows that a large
piece of glacier has broken off the coast of East Antarctica, changing the
shape of the coastline almost overnight. Rob Massom, polar research scientist
at the Antarctic Cooperative Research Center at the University of Tasmania in
Australia, discovered the break purely by chance. "I was looking at sea ice
distribution and noticed something unusual in the satellite images," he said.
"The coastline looked very different than it had in previous images."
Large-scale breakouts like this are rare, according to Massom. Usually
calving events produce only small icebergs. "The breakup of the Ninnis
Glacier Tongue has important implications," said Massom. "To better
understand the Antarctic Ice Sheet’s potential response to global climate
change and its effect on global sea level, it is important to detect and
monitor the calving of large icebergs."
Changes in Antarctic sea ice distribution can have a significant impact on
the survival of marine wildlife, such as penguins and seals, that depend on
sea ice as a platform for breeding, foraging and social interaction. Sources:
New Scientist, November 25, 2000 and NASA Science News