The extent of Arctic Sea Ice, a closely-monitored indicator of a changing climate, showed an unusual late-season growth spurt in March before reaching its maximum of 5.89 million square miles at the end of the month, about average for this time of year, the National Snow and Ice Data Center reports.
The agency reported that the late-season growth was driven "mainly by cold weather and winds from the north over the Bering and Barents seas," although temperatures over the central Arctic Ocean "remained normal and the winter ice cover remained young and thin compared to earlier years."
The graph above captures the timing of 2010 ice extent in relation to 2007 and the average since 1979, while the map at right captures its spatial extent. (Click on the images for larger views.)
The timing of maximum sea ice extent is subject to wide variability, ranging anywhere from mid-February to the end of March, although the average ice extent for March 2010 is part of a long-term trend of decline since 1978 that amounts to 2.6 percent per decade.
The more critical measure is the maximum extent of sea ice melting at the end of the Arctic summer, when exposed ocean water is able to directly absorb solar warmth, a climate-altering circumstance that reached record-low levels in 2007.The Boulder, CO-based Snow and Ice Data Center reported:
"The late date of the maximum extent, although of special interest this year, is unlikely to have an impact on summer ice extent. The ice that formed late in the season is thin, and will melt quickly when temperatures rise."
While the extent of older, thicker multi-year Arctic ice is much less than it was in the 1980s and 1990s, scientists report, the amount of ice surviving the last two summer melt season has increased since the record lows of 2007.
IMAGES: National Snow and Ice Data Center
Tags: Carbon Emissions, Climate Change, Geophysics, Global Warming, Meteorology
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