World's largest ice sheet crumbling faster than previously thought, satellite imagery shows - CNN

But even in East Antarctica, a region whose ice shelves were long considered less vulnerable, "we're seeing more losses than gains," Greene said.

One East Antarctic calving event that took the world by surprise was the collapse and disintegration of the massive Conger-Glenzer ice shelf in March, possibly a sign of greater weakening to come, Greene said.

Eric Wolff, a Royal Society research professor at the University of Cambridge, pointed to the study's analysis of how the East Antarctic ice sheet behaved during warm periods of the past and models for what may happen in the future.

"The good news is that if we keep to the 2 degrees of global warming that the Paris agreement promises, the sea level rise due to the East Antarctic ice sheet should be modest," Wolff wrote in a commentary on the JPL study.

Failure to curb greenhouse gas emissions, however, would risk contributing "many meters of sea level rise over the next few centuries," he said.