Arctic sea ice reaches minimum extent for 2009, third lowest ever recorded

The Arctic sea ice cover appears to have reached its minimum extent for the year, the third-lowest recorded since satellites began measuring sea ice extent in 1979, according to the University of Colorado at Boulder's National Snow and Ice Data Center.

While this year's September minimum extent was greater than each of the past two record-setting and near-record-setting low years, it is still significantly below the long-term average and well outside the range of natural climate variability, said NSIDC Research Scientist Walt Meier. Most scientists believe the shrinking Arctic sea ice is tied to warming temperatures caused by an increase in human-produced greenhouse gases being pumped into Earth's atmosphere.

Atmospheric circulation patterns helped the Arctic sea ice spread out in August to prevent another record-setting minimum, said Meier. But most of the 2009 September Arctic sea ice is thin first- or second-year ice, rather than thicker, multi-year ice that used to dominate the region, said Meier.

The minimum 2009 sea-ice extent is still about 620,000 square miles below the average minimum extent measured between 1979 and 2000 -- an area nearly equal to the size of Alaska, said Meier. "We are still seeing a downward trend that appears to be heading toward ice-free Arctic summers," Meier said.

CU-Boulder's NSIDC will provide more detailed information in early October with a full analysis of the 2009 Arctic ice conditions, including aspects of the melt season and conditions heading into the winter ice-growth season. The report will include graphics comparing 2009 to the long-term Arctic sea-ice record.

Source: University of Colorado at Boulder (news : web)

   

• dachpyarvile - Sep 17, 2009
  • Rank: 3 / 5 (2)
  Yes, we were supposed to have had an ice-free Arctic last year, according to the NSIDC, but that did not happen, now did it?
  
  As to the lack of multi-year ice that once dominated the region, well, it has not yet been multi-years has it? So, it would be expected that there would be one-year and two-year ice since the trend for the last three years has been a cooling trend and last year's precipitation and ice-building was substantial enough to put back much of the mass of ice lost from the previous decade.
  
  But, previous to that there was a warming trend with the loss of much ice. So, again, it is to be expected that there would be more one-year and two-year ice in comparison since it has been one and two years since the change over the last couple years.
  
  I say, let's take a wait and see approach and see what happens over the next few years.
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