After the third-straight year with record or near-record melting of Arctic sea ice, perhaps it's not a surprise that the annual re-freezing of the Arctic is continuing the consistently alarming trend.
December 2009 and January 2010 saw unusually warm conditions across the Arctic (even as North America got blasted with particularly cold air). The result? Arctic sea ice extent is now lower than it was at this point during the record-breaking 2006-2007 cycle that resulted in the record-lowest sea ice extent ever recorded in the summer of 2007. While both the summers of both 2008 and 2009 saw extreme melting far in excess of average, neither quite reached the extent of 2007.
The stage is being set for another significant melt in 2010, though there is still about a month of freezing to go. Arctic sea ice typically reaches its maximum extent for the year sometime around the end of February and the beginning of March.
Satellite records date to 1979, but ice cores and other data indicate that the rate of melting is unprecedented and can only be explained by the heat-trapping accumulation of greenhouse gases in the atmosphere. As ice melts, the darker water that is revealed absorbs more heat than the reflective ice, reinforcing the melting trend.
Greenpeace has predicted that most summer ice could be gone in five years, and the summer could be completely ice-free by 2050. While that may be an extreme view, the trend is heading in that direction eventually, and the extent of melting in the past three years was to an extent not expected for decades, under mainstream scientific predictions of just a few years ago.
As the ice melts, polar bear, Pacific walrus, ribbon seals and other species struggle for survival, and the potential for human use grows -- for oil and gas drilling, and for shipping through once ice-locked channels. More concerning for humans is this: As it becomes clear that the worst-case melting scenarios are taking place, does that mean that the worst-case predictions for other aspects of global warming are inevitable? Wildfires, droughts, crop failure, sea-level rise, massive rates of species extinctions ... each could appear more quickly, and have more severe impacts than the public expects.
Chart: National Snow and Ice Data Center
Meanwhile, back at home, Americans are growing less and less concerned. A new Yale University-George Mason University survey of 1,001 U.S. residents (some eager college student earned his work study money at the phone bank with that extra call, apparently) found that just 50% of Americans are at all worried about global warming, a decrease of 13 points from fall 2008. Just 57% believe global warming is happening now, a 14-point decline. And fewer than half -- just 47% -- believe global warming is caused mostly by human activities. Fewer people believe global warming will affect U.S. residents, other humans or even other species.
Enter your city or zip code to get your local temperature and air quality and find local green food and recycling resources near you.