Arctic sea ice extent reached a historical minimum in October 2007, prompting claims that it could be ice-free in summer in 10 or 20 years.  In 2008 and 2009, summer extent has recovered somewhat.

Two points must be borne in mind:

• What matters is sea ice volume.  The ice has thinned, so the decline continues.
• The main cause of the melt has been patterns of wind and ocean currents, transporting more heat into the Arctic.  Of course, such changes may themselves have resulted from global warming, but it is too early to say.
  

Whatever the explanation, sea ice melt will reduce albedo, resulting in more warming.  Total melt would threaten the Greenland ice sheet, and if that goes sea levels would rise by metres (but this will take centuries).  So even if it has nothing to with increased GHGs, it is another reason for avoiding doing anything that tends to warm the planet.