The West Antarctic ice sheet has long been considered at risk due to global warming, and today two studies report, based on new evidence, an unstoppable retreat has begun. The ice sheet holds enough water to raise sea level by several feet.
The glacier's slow degradation would have a destabilizing effect on the rest of the ice sheet, which holds enough ice to raise global sea level by 10 to 13 feet, according to researchers.
The "grounding line" between the ice sheet and ocean is retreating inward based on airborne and satellite data, said Eric Rignot, lead author of a study published in Geophysical Research Letters, at a press conference held by NASA.
"Today we present observational evidence that the [ice sheet] has gone into irreversible retreat," Rignot said. "It has reached the point of no return."
The sea-level rise projections from the Intergovernmental Panel on Climate Change will likely need to be revised upward, based on these findings, said Sridhar Anandakrishnan, professor of geosciences at Pennsylvania State University, University Park. Anandakrishnan spoke at the NASA press conference, but was not involved in the study.
"The authors have shown that part of Antarctica is undergoing enormous change," Anandakrishnan said. "That ice has nowhere to go but in the ocean. This results in a rise in sea level around the globe."