Sea ice is melting faster than projected, study says

Arctic sea ice is melting three times faster than many scientists had projected, U.S. researchers reported just days ahead of the next major international report on climate change.

Scientists at the National Center for Atmospheric Research and the University of Colorado in Boulder on Monday said they had concluded, using actual measurements, that Arctic sea ice had declined at an average rate of about 7.8% per decade between 1953 and 2006.

By contrast, 18 computer models used by the Intergovernmental Panel on Climate Change, a U.N.-sponsored climate research group, estimated an average rate of decline of 2.5% per decade over the same period, the researchers said.

International delegates are meeting in Bangkok, Thailand, this week to hammer out the final wording of the third IPCC report.

The new study’s observations and the IPCC’s projections are for September, when Arctic sea ice is typically at its low point for the year.

The researchers said their observations indicated that the retreat of summertime Arctic sea ice was about 30 years ahead of the pace projected by climate models. “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 National Center for Atmospheric Research scientist Marika Holland, a study coauthor.