www.nytimes.com/2014/05/13/science/earth/collapse-of-parts-of-west-antarctica-ice-sheet-has-begun-scientists-say.html?partner=rss&emc=rss&_r=1
"The basic problem is that much of the West Antarctic ice sheet sits below sea level in a kind of bowl-shaped depression the earth. As Dr. Mercer outlined in 1978, once the part of the ice sheet sitting on the rim of the bowl melts and the ice retreats into deeper water, it becomes unstable and highly vulnerable to further melting.
Richard B. Alley, a climate scientist at Pennsylvania State University who was not involved in the new research but has studied the polar ice sheets for decades, said he found the new papers compelling. Though he has long feared the possibility of ice-sheet collapse, when he learned of the new findings, it shook me a little bit, Dr. Alley said.
He added that while a large rise of the sea may now be inevitable from West Antarctica, continued release of greenhouse gases will almost certainly make the situation worse. The heat-trapping gases could destabilize other parts of Antarctica as well as the Greenland ice sheet, causing enough sea-level rise that many of the worlds coastal cities would eventually have to be abandoned."