The passage of time has not been kind to the Arctic's fortunes: Where scientists once predicted the Arctic would be ice-free by the end of the century, they revised their estimates in recent months to 2030 and now - stunningly - to 2013. Presenting the findings of his modeling studies at the American Geophysical Union meeting in San Francisco, Wieslaw Maslowski, a professor at the Naval Postgraduate School, explained that earlier projections had low-balled the real values by not accounting for some of the processes driving the ice loss.
Even worse, he conceded that his own estimates may be on the optimistic side, explaining that the models he had run - using data from 1979 to 2004 - did not take into account the ice cover minima reached in 2005 and 2007. "Our projection of 2013 for the removal of ice in summer is not accounting for the last two minima, in 2005 and 2007. So given that fact, you can argue that may be our projection of 2013 is already too conservative." said Maslowski.Maslow believes earlier estimates missed out on some key melting processes; those issues could be partially resolved if future models incorporated more realistic representations of warm water movement into the Arctic from the Pacific and Atlantic Oceans. Peter Wadhams of Cambridge University remarked that past models did not sufficiently take into account the ice-albedo feedback effect, which occurs when water is heated by solar radiation, leading to more warming and melting.
Mark Serreze, a scientist with the US National Snow and Ice Data Center (NSIDC), still believes 2030 is a reasonable estimate, deeming Wieslaw's projections as "a little aggressive . . . simply because the luck of the draw means natural variability can kick in to give you a few years in which the ice loss is a little less than you've had in previous years." Either way, the melting of the Arctic ice cap within our lifetimes now seems inevitable.
Via ::BBC News: Arctic summers ice-free 'by 2013' (news website)