The last week of August, 2008 saw its sea ice melt season become the second lowest in modern recorded history -- surpassing the 2005 minimum sea ice figures.
Image illustrates September minimum sea ice concentrations for 2008
Image Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio
According to the National Snow and Ice Data Center, atmospheric conditions have dampened sea ice movement and as a result the 2009 Arctic sea ice melt season did not surpass the record values of 2007. As of September 12, 2009 it appears that Arctic sea ice has reached its minimum values for the year, 5.10 million square kilometers. These values are some 970,000 square kilometers above the 2007 figures but still below the historical 1979-2000 benchmark.
If the deteriorating Arctic polar ice mass continues on its present course, a process known as a positive sea ice-albedo feedback will amplify. The process develops when incoming solar radiation emitted from the sun decreases the surface albedo and in turn strengthens the presence of melt ponds on the top portion of the sea ice – precursor to the creation of open water and the development of the lateral-melt characteristic (melting from underneath the sea ice). This cascading effect propels rising surface temperatures and among other things reduces snow cover and sea ice concentrations throughout various regions of the Arctic. To that end, successive winters will produce thinner sea ice and therefore melt easier the following summer – compromising the thickness and extent of sea ice.
The 2009 Arctic sea ice extent is proving to hold the sea ice-albedo feedback assumption correct. Thinner first-year sea ice (compared to thicker multi-year sea ice) now accounts for over 70 percent of the total sea ice coverage compared to approximately 40-50 percent between the 1980s and 1990s.
