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Climate change: Arctic ice melting faster, sea level to rise more, report says

May 4, 2011 | 12:31 pm

Icebergmelt

Sea levels will rise more dramatically than was predicted nearly four years ago by the Intergovernmental Panel on Climate Change, a new study of arctic conditions concludes.

The Arctic ice study by the International Arctic Monitoring and Assessment Program, titled Snow, Water, Ice and Permafrost in the Arctic (SWIPA), says that the feedback loops scientists have been warning about already are accelerating glacial melting in the Arctic, which accounted for 40% of sea-level rise chronicled annually from 2003 through 2008.

The executive summary of the report says:

The greatest increase in surface air temperature has happened in
autumn, in regions where sea ice has disappeared by the end of summer. This
suggests that the sea is absorbing more of the sun’s energy during the summer
because of the loss of ice cover. The extra energy is being released as heat
in autumn, further warming the Arctic lower atmosphere. Over land, the
number of days with snow cover has changed mostly in spring. Early snow
melt is accelerated by earlier and stronger warming of land surfaces that
are no longer snow-covered.

These processes are termed "feedbacks." Snow feedbacks are well known. The sea-ice feedback
has been anticipated by climate scientists, but clear evidence for it
has only been observed in the Arctic in the past five years.

Sea levels are expected to rise by 35 to 63 inches by 2100, far more than the 2007 projection of 7 to 23 inches made by the IPCC, the report says. Temperatures from 2005 through 2010 have been the highest since records began in 1880, the study shows.

The melting will not only affect sea levels; it has the potential to alter sea currents that regulate climate, the report warns:

All the main sources of freshwater entering the Arctic Ocean are increasing -- river discharge, rain/snow, and melting glaciers, ice caps, and
the Greenland Ice Sheet. Recent calculations estimate that an extra
7700 km3 of freshwater -– equivalent to one meter of water over the entire land
surface of Australia -– has been added to the Arctic Ocean in recent years.
There is a risk that this could alter large-scale ocean currents that affect
climate on a continental scale.

The report will be presented to the foreign ministers of Arctic nations next week, and is likely to stir more controversy over stalled efforts to curb planet-warming greenhouse gases.

"It is deeply concerning that these latest scientific findings blow previous estimates out of the water," Lou Leonard, managing director of the World Wildlife Fund's Climate Change Program, said in a statement Wednesday. "I'm not sure what is more alarming, the glacial pace of Congress to reduce carbon pollution or the astounding rate of melting Arctic ice."

RELATED:

Bubbles of warming, beneath the ice

The melting Arctic: a bigger-than-estimated impact on climate

Arctic sea ice reaches historic summer low

-- Geoff Mohan

Photo: An iceberg melts off Greenland in 2005. Credit: John McConnico / Associated Press

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