Arctic sea ice melting three times faster than believed

Published in India
America Wednesday, May 02, 2007
From correspondents in Washington, United States, 11:31 AM IST

The vast stretch of sea ice in the Arctic, which helps regulate the world's climate, is shrinking three times faster than previously predicted, according to a new study.

Researchers at the National Snow and Ice Data Centre (NSIDC) said that actual observations, using data from satellites and earlier aircraft and ship voyages, showed ice has melted at a much faster pace over the last 50 years than predicted by current computer models, according to a study published Tuesday.

Those computer models were leaned on when the Intergovernmental Panel on Climate Change (IPCC) earlier this year predicted that Arctic sea ice will disappear completely over the summer months some time between 2050 and 2100, raising the temperature of the world's oceans with potentially devastating effects on marine life.

The NSIDC research suggests that the IPCC's timeline is about 30 years too conservative.

The study comes as scientists and government representatives are meeting in Bangkok this week to discuss the third installment of the IPCC report, which focuses on how to combat global warming.

The NSIDC findings, published Tuesday in a journal of the American Geophysical Union, found that Arctic sea ice cover in September - which has the least amount of ice cover of any month - declined by about 7.8 percent per decade between 1953 and 2006.

That compares to only 2.5 percent predicted on average by computer simulations that looked at the same period. No previous model has given a melting rate of more than 5.4 percent, according to the study.

'This suggests that current model projections may in fact provide a conservative estimate of future Arctic change, and that the summer Arctic sea ice may disappear considerably earlier than IPCC projections,' according to Julienne Stroeve, who led the NSIDC study.

The discrepancy could be because the effect of manmade greenhouse gases on ice melting has until now been underrated, according to Stroeve.
Melting ice in the Arctic is a crucial element of global warming. The vast ice mass helps cool the planet by reflecting the sun's ray back into space throughout the year. Open water absorbs the sunrays instead, raising the temperature of the world's oceans