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 had 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, potentially causing enough sea-level rise that many of the world’s coastal cities would eventually have to be abandoned.

“If we have indeed lit the fuse on West Antarctica, it’s very hard to imagine putting the fuse out,” Dr. Alley said. “But there’s a bunch more fuses, and there’s a bunch more matches, and we have a decision now: Do we light those?”

via Scientists Warn of Rising Oceans From Polar Melt – NYTimes.com.