Arctic Sea Ice Reaches Record Low

"Today, the Northern Hemisphere sea ice area broke the record for the lowest recorded ice area in recorded history." So begins a statement on a scientist's Web site, posted yesterday and first reported in The New York Times.

Research by William T. Chapman, of the Polar Research Group at University of Illinois, shows that the the amount of floating ice in the Northern Hemisphere has reached the smallest extent ever recorded, and a full month ahead of the typical low point of the year. Other scientists, quoted in the Times story, differed only in assessments about whether the extent of sea ice had reached a record minimum, or was on the cusp of doing so. The record broken was not old -- having been set just two summers ago.

For more information on this research, including additional images, see The Cryosphere Today. While both global warming trends and year-specific weather conditions contributed, the melting of the ice is another worrying sign about the pace of warming in the Arctic. As sea ice disappears, ocean waters occupy more of the surface area of the Arctic.

Because the dark waters absorb more heat from sunlight than white ice, the region will radiate more heat, which leads to the melting of more ice and still more heat. It's what scientists call a positive feedback loop, and the concern is that a tipping point might be reached when the melting of ice during the long sunny Arctic summer can't be offset by the regeneration by the long dark Arctic winter.

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