Sea ice at the North Pole

Last fall the the US National Snow and Ice Data Center in Boulder, Colorado reported that sea ice around the North Pole reached a low of 4.24 million square kilometers (source). Today Andy Revkin reports in DotEarth that

Fourteen research teams studying the impacts of warming on the Arctic Ocean have issued independent projections of how the sea ice will behave this summer, and 11 of them foresee an ice retreat at least as extraordinary as last year's or even more dramatic. The other three groups that issued a numerical estimate see the ice extent heading back toward, but not equaling, the average minimum for summers since satellites began tracking the comings and goings of Arctic sea ice in 1979. Five other groups chose not to issue a numerical estimate.

This is an example of legitimate scientific debate about the consequences of global climate change. Some experts think the extent of the decline (illustrated in the animation from NASA below) has been misstated. A single season won't be enough to settle the dispute, but it will provide data to the investigators involved that help them better to understand the forces that affect the extent of sea ice around the North Pole.