Evolution of the 2007-2008 Arctic sea ice cover and prospects for a new record in 2008

The record Arctic sea ice minimum in 2007 has heightened debate on whether the Arctic Ocean has reached a tipping point, leading to a rapid transition towards a seasonal ice cover. Here, we review the 2007-2008 winter and spring ice and atmosphere conditions and assess how likely another record minimum is in summer 2008. At the end of June, 67% of the Arctic Ocean was covered by younger-than-average ice and only 5% was covered by older than-average-ice. Using a simple estimate based on ice survival rates, a new record low is reached in 2008 in 24 of 25 cases. With a more complex linear regression model, we suggest the September sea ice extent will be 4.40 million square kilometers, with a 40% chance that 2008 will set a new record low Arctic ice minimum.