A "catastrophic" melting of the Arctic Ocean ice cap in August -- which led to a record low ice extent -- was not expected by any of the science teams that annually attempt to forecast Arctic ice, reports The Atlantic. It's still possible that the melting will end earlier than usual and make this summer more typical of recent years' meltoff, but that seems unlikely.
What's befuddling about 2012, relative to [the previous record year] 2007, is that the Arctic has not seen the kind of ice-melting weather that 2007 did. "I'm at a loss at this loss," wrote sea ice blogger (yes they exist!) Neven Acropolis. "The 2007 record that stunned everyone, gets shattered without 2007 weather conditions."
Unknown unknowns aside, one frightening possibility exists. For years, scientists have been warning that Arctic sea ice is thinning. Thinner ice melts more quickly. But when we traditionally measure sea ice, scientists aren't looking at the mass of the ice, just the surface extent.
Unfortunately, as the University of Washington's Polar Science Center explains, we can't monitor sea ice volume easily.
If indeed this summer's meltoff is the result of thin ice, predictions for the first ice-free summer in the Arctic may be moved up drastically.
Read more at The Atlantic: The Mystery at the Heart of This Year's Record-Setting Arctic Ice Melt