Scientists digging into the ancient history of Antarctica’s ice sheets have uncovered evidence of an “extreme” melting event that drove rapid and significant sea level rise. Taking place more than 100,000 years ago, the scientists see this ice melt as a cautionary tale for climate change, largely because it was likely set off by a temperature increase of less than 2° C (3.6° F), the upper limit of the goal laid out by the Paris Climate Agreement.
Some scientists believe that at some time during the Last Interglacial, global mean sea levels were around six to nine meters (20 to 30 ft) higher than they are today, with some scientists suspecting they could have been as much as 11 m (36 ft) higher. A number of factors are thought to have contributed to this, including melting glaciers, thawing of the Greenland Ice Sheet and expanding oceans as a result of warmer waters. The team says this new study indicates West Antarctica had a big role to play, singlehandedly causing a rise in sea levels of more than three meters (9.8 ft).
We now have some of the first major evidence that West Antarctica melted and drove a large part of this sea level rise,” says Professor Turney.
What concerns the scientists with regard to the future is how vulnerable the West Antarctic Ice Sheet appears to be to warmer waters. This is because it rests on the seabed rather than the ground, like the East Antarctic Ice Sheet, and ocean water fills cavities underneath it that melts the ice from below.
“The West Antarctic Ice Sheet is sitting in water, and today this water is getting warmer and warmer,” says Turney.
“Our study highlights that the Antarctic Ice Sheet may lie close to a tipping point, which once passed may commit us to rapid sea level rise for millennia to come,” says study co-author Professor Christopher Fogwill, from the UK’s University of Keele. “This underlines the urgent need to reduce and control greenhouse gas emissions that are driving warming today.”
https://newatlas.com/environment/melting-antarctic-ice-sheet-sea-level-rise/