“It is too early to reassure that all will stabilize, and similarly there is no way to predict a catastrophic collapse,” [says] Eric Rignot [of NASA's Jet Propulsion Laboratory]. “But things are definitely far more serious than anyone would have thought five years ago.”-- from In Greenland, Ice and Instability.
P.S. 13 Jan: Antarctic ice loss speeding up:
[Eric Rignot, an ice sheet expert at the University of California at Irvine] agrees that the trend might not continue: the triggers and feedbacks of glacial flows are poorly understood, he notes. But he still thinks the IPCC has been overly cautious in not reporting the possibilities of ice loss, which he says could occur in the next century. “Each time I look at some new data, I am astonished.”