Climate Fact: Shrinking Arctic Sea Ice
The Arctic sea ice reaches its maximum extent in March and its minimum extent in September. The 2008 September minimum was the second-lowest recorded (the 2007 minimum was the lowest) since satellite observations started in 1979. This 2008 minimum was 34 percent below the 1979-2000 average, and the total average extent of the Arctic sea ice is declining at a rate of 11.7 percent per decade. The amount of “old” sea ice (ice that survives the previous year’s melt and is considered to be less vulnerable to future melting) has been shrinking particularly rapidly, and a record for the percentage of the Arctic composed of first year ice was set in March of 2008 at 73 percent. 2008 featured a different wind pattern than 2007, which worked to “spread out” the ice pack and bring slightly cooler air temperatures and cloudier skies to the Arctic. Persistently warm ocean waters, however, allowed melting to continue quickly even after the day length began to shrink, and as a result, August of 2008 featured the greatest amount of ice loss of any August on record.
Seasons: Winter, Spring, Summer, Fall
Source: “Arctic sea ice down to second-lowest extent; likely record-low volume.” National Snow and Ice Data Center. Updated 2 October 2008. Accessed 6 December 2008 <http://nsidc.org/news/press/20081002_seaice_pressrelease.html#fig5>