Rapidly disappearing: A boat skims through melting ice on the western coast of Greenland. Flying low over the vast, white expanse of Greenland's Ilulissat glacier, the effects of global warming in the Arctic are painfully visible.
Credit: AFP/STEEN ULRIK JOHANNESSEN
WASHINGTON DC: Some 80% of Arctic ice may disappear in 30 years, not 90 as scientists had previously estimated, according to a new study on the impact of global warming.
"The amount of the Arctic Ocean covered by ice at the end of summer by then could be only about one million square kilometres," said U.S. researchers who authored the study published in the journal Geophysical Research Letters.
Ecosystem upheavel
"That's compared to today's ice extent of 4.6 million square kilometres" they added, warning the development "raises the question of ecosystem upheaval."
The scientists made their projections based on models that took accounted for changes in Arctic ice, which saw "dramatic declines" at the end of summer in 2007 and 2008, when the ice surface dropped to 4.3 and 4.6 million square kilometres, respectively.
The models pointed to a "nearly ice-free" Arctic in just 32 years, with some of the models making the same prediction for 11 years from now.
"In recent years, the combination of unusual warm temperatures from natural causes and the global warming signal have worked together to provide an earlier summer sea-ice loss than was predicted," said study author James Overland of the National Oceanic and Atmospheric Administration (NOAA).
"Boon for shipping"
Overland and co-author Muyin Wang of the University of Washington in Seattle, said earlier models had predicted the event would not take place before the end of the 21st century.
Maps illustrating Overland and Wang's models showed a nearly ice-free Arctic Ocean, although some ice would remain along northern Canada and Greenland, where powerful winds make for very thick layers of ice.
The researchers noted one benefit of less ice in the Arctic: "a boon for shipping and for extracting minerals and oil from the seabed."
