Arctic Ice melting much quicker than computer models projections

Arctic sea ice is melting at a significantly faster rate than projected by even the most advanced computer models, a new research by scientists at the National Center for Atmospheric Research and the University of Colorado's National Snow and Ice Data Center (NSIDC) has revealed.

Washington, May 1 : Arctic sea ice is melting at a significantly faster rate than projected by even the most advanced computer models, a new research by scientists at the National Center for Atmospheric Research and the University of Colorado's National Snow and Ice Data Center (NSIDC) has revealed.

"While the ice is disappearing faster than the computer models indicate, both observations and the models point in the same direction: the Arctic is losing ice at an increasingly rapid pace and the impact of greenhouse gases is growing," said NCAR scientist Marika Holland, one of the study's co-authors.

For their study, the authors compared model simulations of past climate with observations by satellites and other instruments.

Earlier models suggested that on an average, loss in September ice cover was 2.5 percent per decade from 1953 to 2006, while the fastest rate of September retreat in any individual model was 5.4 percent per decade. Traditionally, September marked the yearly minimum of sea ice in the Arctic.

But, newly available data sets, blending early aircraft and ship reports with more recent satellite measurements, which are considered more reliable than the earlier records, showed that the September ice actually declined at a rate of about 7.8 percent per decade during the 1953-2006 period.

"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," said Julienne Stroeve of the NSIDC, and leader of the study team.

The study further indicated that, because of the disparity between the computer models and actual observations, the shrinking of summertime ice was about 30 years ahead of the climate model projections.

According to the study, the actual rate of sea ice loss in March, which averaged about 1.8 percent per decade in the 1953 -2006 period, was three times larger than the mean from the computer models.

Researchers said the Arctic could get seasonally free of sea ice earlier than the IPCC- projected timeframe of any time between 2050 and 2100.

They said computer models might also fail to capture the full impact of increased carbon dioxide and other greenhouse gases in the atmosphere.

"Whereas the models indicate that about half of the ice loss from 1979 to 2006 was due to increased greenhouse gases, and the other half due to natural variations in the climate system, the new study indicates that greenhouse gases may be playing a significantly greater role," the researchers wrote in their study, "Arctic Sea Ice Decline: Faster Than Forecast?" - appearing online in the Geophysical Research Letters.

ANI