Sunday, December 25, 2011

A Near-Record Year in Arctic Sea Ice

Over the past year, Arctic sea ice has alternated between record and near-record low levels. In early September, the extent of sea ice either hit an all-time low or came close, depending on the model you used to slice the data up. Between June and September, cargo ships crossed the Arctic Ocean as if they had been doing it all along. The year ends with ice extent near the lowest it has ever been at this time of year. It is harder to guess at the thickness of sea ice, but the ice this year probably has also been the thinnest ever.

And all this happened with nothing more than the usual fluctuations in the weather. No one can predict when the Arctic sea ice could melt away completely because it would take only one spring of extreme weather conditions to make that happen.