The ice in the Arctic Ocean had retreated to its lowest point on September 16. Winter has set in and the ice should start reforming on the sea.
The problem is that the ice is melting faster in the summer than it is forming in the winter. Less ice cover means more heat in the atmosphere and the surface layers of the ocean, which means more melting.
This year, the sea ice covered only 1.32 million square miles, half the 1979-2000 average. 2012 broke the previous record minimum set in 2007 of 1.61 million square miles.
A storm in early August produced an impressive melting sequence as shown in the video below.
This second video shows the Arctic sea ice retreat from the beginning of August to mid-September.