We recall last year how projections of new lows in Arctic sea ice extents were boldly made, and eagerly publicised by the catastrophe-obsessed media. It made for good headlines, but they were all wrong. See here June Outlook Report.
This year Germany’s Alfred Wegener Institute AWI here and the KlimaCampus of the University of Hamburg are taking another shot at it, along with a dozen or so other fortune tellers. The AWI press release states:
The projection of the KlimaCampus of the University of Hamburg is 4.7 million sq km, which is more negative than the 5.2 million sq km made by the AWI scientists. Yet both research centres do not exclude a record low of 4.3 million set in 2007 being reached.
Decisive factors like ice thickness and how the rest of the summer develops are unknown and do not allow for accurate projections. Yet the AWI is projecting a sea level that is almost a million sq km over 2007. They know that the ice in the central Arctic is thick, but probably don’t want to say it publicly. Indeed, most of the sea ice fortune tellers are projecting 2010 to finish higher than 2008.
Both teams used different methods for their projections. Prof. Rüdiger Gerdes and his team at the AWI worked out a model together with the scientific companies OASys and FastOpt that uses oceanic drift buoys and satellite data for measuring the movement of ice. The projection will be revised each month during the summer. Dr. Gerdes says:
Currently we calculate with 80% probability that the sea ice extent will be between 4.7 million and 5.7 million sq km in September. The projections will become more precise as summer progresses.
Meanwhile the KlimaCampus-Team of Prof. Lars Kaleschke takes satellite photos of the Arctic sea ice for each day of 2010 and compares them to the same day of each year from 2003 to 2009.
The number and size of the ice-free areas are indicators for subsequent ice developments. These dark spots store more solar energy in early summer and thus enhance ice melt during the polar summer, as the sun does not disappear until September.