Arctic Sea Ice Record Low

Arctic Sea Ice Record Low



2007 September -   Scientists from the 
University of Colorado at Boulder's National Snow and Ice Data Center said 
today that the extent of Arctic sea ice appears to have reached its 
minimum for 2007 on September 16, shattering all previous lows since 
satellite recordkeeping began nearly 30 years ago. 
The sea ice extent is the total area of all Arctic regions where ice 
covers at least 15 percent of the ocean surface. Arctic sea ice generally 
reaches its minimum extent in September and its maximum extent in March. 
The Arctic sea ice extent on September 16 stood at 1.59 million square 
miles, or 4.13 million square kilometers, as calculated using a five-day 
running average, according to the team. 
Compared to the long-term minimum average from 1979 to 2000, the new 
minimum extent was lower by about one million square miles - an area about 
the size of Alaska and Texas combined, they reported. 
The minimum also breaks the previous minimum set on September 20 and 21, 
2005 by about 460,000 square miles, an area roughly the size of Texas and 
California combined, they found. 
Scientists blame the declining Arctic sea ice on rising concentrations of 
greenhouse gases that have elevated temperatures from 2 degrees F to 7 
degrees F across the Arctic and strong natural variability in Arctic sea 
ice. 
The research group said determining the annual minimum sea ice is 
difficult until the melt season has decisively ended. But the team has 
recorded five days of little change, and even slight gains in Arctic sea 
ice extent this September, so reaching a lower minimum for 2007 seems 
unlikely, they reported. 
"The amount of ice loss this year absolutely stunned us because it didn't 
just beat all previous records, it completely shattered them," said 
CU-Boulder senior scientist Mark Serreze of the National Snow and Ice Data 
Center. 
The researchers used satellite data from NASA, the National Oceanic and 
Atmospheric Administration and the U.S. Department of Defense, as well as 
data from Canadian satellites and weather observatories for the study. 

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