The Arctic Ocean could be nearly ice-free in 30 years—60 years sooner than was previously predicted, according to a paper published last week by the American Geophysical Union. The new projections, which appear in the April 3, 2009, Geophysical Research Letters, are based on data from six global-climate models most suited for assessing sea ice, according to University of Washington climate scientist Muyin Wang and James Overland, an oceanographer with the National Oceanic and Atmospheric Administration (NOAA) Pacific Marine Environmental Laboratory in Seattle.
Models also were chosen that are able to reflect the difference between summer and winter ice packs, which demonstrates a model’s ability to take into account changing amounts of solar radiation from summer to winter, states Wang.
The amount of the Arctic Ocean covered by ice at the end of summer in 30 years could be only about 620,000 square miles—in contrast to today’s 2.8 million square miles. These open waters could benefit the shipping industry and allow for mineral and oil extraction from the seabed, but would cause serious ecosystem upheaval.
“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 when scientists considered the effects from human-caused carbon dioxide alone,” says Overland.