The 2011 Arctic sea ice extent maximum that annually marks the beginning of the melting season appears to be the lowest ever, according to scientists at the University of Colorado Boulder’s National Snow and Ice Data Center.
The CU-Boulder research team believes the lowest annual maximum ice extent of 5,650,000 square miles occurred on March 7. The maximum ice extent was 463,000 square miles below the 1979-2000 average. This could cover an area slightly larger than the states of Texas and California combined.
Almost all climate scientists believe shrinking Arctic sea ice is tied to warming temperatures caused by an increase in anthropogenic greenhouse gas emissions. Some of these scientists worry that the Arctic will be completely ice free within the next few decades.
“I’m not surprised by the new data because we’ve seen a downward trend in winter sea ice extent for some time now,” said CU-Boulder Research Scientist Walt Meier of the National Snow and Ice Data Center, who participated this study. He also mentioned that the seven lowest maximum Arctic sea ice extents measured by satellites all have occurred in the last seven years.
Meier also explains that the Arctic sea ice functions like an air conditioner for the global climate system. It naturally cools the air and water masses, playing a key role in ocean circulation and reflecting solar radiation back into space. During the summer months in the Arctic, sunlight is absorbed by increasing amounts of open water, causing surface temperatures to rise and more ice to melt.
“I think one of the reasons the Arctic sea ice maximum extent is declining is that the autumn ice growth is delayed by warmer temperatures and the ice extent is not able to ‘catch up’ through the winter,” said Meier. “In addition, the clock runs out on the annual ice growth season as temperatures start to rise along with the sun during the spring months.”
Early this month CU-Boulder’s National Snow and Ice Data Center will issue a formal announcement on the 2011 maximum sea ice extent with a full analysis of the winter ice growth season, including graphics comparing 2011 to the long-term record.
For updates and announcements, check out the Arctic Sea Ice News & Analysis page.
Copyright © 2011 by Marine Science Today, a publication of OceanLines LLC