New research from the Potsdam Institute for Climate Impact Research and Universidad Complutense de Madrid has lowered the best estimate for the irreversible collapse of the Greenland Ice Sheet down to 1.6 °C, making the ice sheet more vulnerable than previously thought to global warming. The previous best estimate was 3.1 °C. As we currently have 0.8 °C of global warming, by the middle of the century we could easily pass this new threshold unleashing an ultimate sea level rise of several metres.
Already we have seen record summer melting in Greenland in 2010, and near record mass loss in 2011. According to NOAA the melt season in 2011 lasted up to 30 days longer than average and it affected 31 percent of the ice sheet surface, making 2011 one of just three years since 1979 where melt area exceeded 30 percent. Polar regions are warming much faster and to a greater degree than any other latitude on earth.