[Vision2020] Geophysical Research Letters, 4/3/09: Ice-Free Arctic Summers Likely Sooner Than Expected

[Ted Moffett]

 Ice-Free Arctic Summers Likely Sooner Than Expected

April 2, 2009

http://www.noaanews.noaa.gov/stories2009/20090402_seaice.html
Summers in the Arctic may be ice-free in as few as 30 years, not at the end
of the century as previously expected. The updated forecast is the result of
a new analysis of computer models coupled with the most recent summer ice
measurements.

“The Arctic is changing faster than anticipated,” said James Overland, an
oceanographer at NOAA’s Pacific Marine Environmental
Laboratory<http://www.pmel.noaa.gov/>and co-author of the study, which
will appear April 3 in
*Geophysical Research Letters*. “It’s a combination of natural variability,
along with warmer air and sea conditions caused by increased greenhouse
gases.”

Overland and his co-author, Muyin Wang, a University of Washington research
scientist with the Joint Institute for the Study of the Atmosphere and Ocean
in Seattle, analyzed projections from six computer models, including three
with sophisticated sea ice physics capabilities. That data was then combined
with observations of summer sea ice loss in 2007 and 2008.

The area covered by summer sea ice is expected to decline from its current
4.6 million square kilometers (about 1.8 million square miles) to about 1
million square kilometers (about 390,000 square miles) – a loss
approximately two-fifths the size of the continental U.S. Much of the sea
ice would remain in the area north of Canada and Greenland and decrease
between Alaska and Russia in the Pacific Arctic.

“The Arctic is often called the ‘Earth’s refrigerator’ because the sea ice
helps cool the planet by reflecting the sun’s radiation back into space,”
said Wang. “With less ice, the sun’s warmth is instead absorbed by the open
water, contributing to warmer temperatures in the water and the air.”

NOAA understands and predicts changes in the Earth’s environment, from the
depths of the ocean to the surface of the sun, and conserves and manages our
coastal and marine resources.

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Vision2020 Post: Ted Moffett
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