2009 Arctic Sea Ice Minimum Shows Slight Recovery but Remains Low Overall
07.10.2009 - Water & Oceans, Ice & Snow, Other, Arctic
The 2009 minimum sea ice extent was the third lowest on record since the beginning of satellite measurements in 1979, which meant a slight recovery in 2009 compared to the minimum extents of 2007 and 2008. However National Snow and Ice Data Center (NSIDC) Director Dr. Mark Serreze cautioned that "there's no reason to think that we're headed back to conditions seen back in the 1970s." The past five years have seen the five lowest sea ice extents on record.
The average sea ice extent for September 2009 was 5.36 million km2, about 1.06 million km2 greater than the measurements of 2007 and 690.000 km2 in 2008. However when compared to the 1979-2000 average, the 2009 sea ice extent was lower by a whopping 1.68 million km2 - and the trend in sea ice extent is still declining at a rate of 11.2% per decade relative to the average 1979-2000 sea ice extent.
Despite the increase in surface area, the current sea ice cover is comprised mostly of vulnerable young, thin ice, with first-year and second-year ice making up 49% and 32% respectively of the total sea ice extent, and more solid multiyear ice only comprising19%. Hopes are that the younger ice will become thicker over the winter, making the sea ice more stable over the next few years so it can survive melting in future summers. But it would have to buck the overall trend of the last 30 years to do so.
Sea surface temperatures were also slightly lower than in 2007 and 2008, yet remained higher than normal, according to Dr. Mike Steele of the University of Washington in Seattle. This was mostly due to cooler conditions caused by cloudier skies and changing atmospheric patterns in September and August, which allowed the sea ice to spread.
