Nature Geoscience 6, 274–278 (2013); published online 10 March 2013; corrected after print 29 April 2013.

In the version of this Letter originally published, in the first sentence of the final paragraph, the 1992–2010 percentage increase in freshwater flux from the GrIS into the North Atlantic Ocean (as reported in ref. 25) was incorrectly stated to be 136%. The correct figure is 38%. This has been corrected in the PDF and HTML versions.