May 3, 2007

CLIMATE CHANGE

Arctic Sea Ice Is Melting Fast

Researchers find that Arctic ice is disappearing much faster than predicted in UN models

Bette Hileman

Arctic sea ice is melting at a much faster rate than projected by the most advanced computer models, says a government-funded study published online May 1 in Geophysical Research Letters (DOI: 10.1029/2007GL029703, 2007).

Steve Deyo/University Corp. for Atmospheric Research

SEPTEMBER ICE Arctic sea ice is melting faster than projected by computer models. The dotted line represents the average rate of melting indicated by computer models, with the blue area indicating the spread among the different models. The red line shows the actual rate of Arctic ice loss.

In February, the United Nations Intergovernmental Panel on Climate Change concluded on the basis of computer models that September sea ice in the Arctic had declined an average of 2.5% per decade between 1953 and 2006. (September marks the yearly minimum of Arctic sea ice.) In the new study, scientists from the National Center for Atmospheric Research (NCAR) and the National Snow & Ice Data Center, in Boulder, Colo., compared decades of measurements by ships, airplanes, and satellites and found that the area of September sea ice actually declined 7.8% per decade over that period. As a consequence, they predict that if greenhouse gas emissions are not reduced, the Arctic will be ice-free in September as soon as 2020.

"Although the ice is disappearing faster than the computer models indicate, both the 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," says NCAR scientist Marika M. Holland, one of the study???s coauthors.

Chemical & Engineering News

ISSN 0009-2347

Copyright © 2011 American Chemical Society