If melting ice shuts down the Atlantic circulation, the effects will be catastrophic.
Accelerating Greenland glaciers are dumping more and more fresh water into the North Atlantic.
The oceans are soaking up a lot of the excess carbon dioxide. Surface waters may soon become saturated and greenhouse gases will build up faster still.
Any reduction in carbon fixing as forests and ocean ecosystem fail would only compound the effect
Page 42-46. 15 April 2006 New Scientist