For the past few years climate scientists have been warning that Earth is nearing a tipping point, a juncture after which damage is irreversible and there’s no turning back. Two scientific teams have found that this is now happening in a section of the Western Antarctic ice sheet in a melt that can raise sea level by 10 feet or more, making many coastal cities uninhabitable within just a few hundred years.
"The collapse of this sector of West Antarctica appears to be unstoppable," said Eric Rignot, lead author of a study conducted by the University of California at Irvine and NASA's Jet Propulsion Laboratory in Pasadena, California. "The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers. At this point, the end of this sector appears to be inevitable."
Pulling together 40 years of data, the researchers saw that the glaciers draining into the Amundsen Sea “have passed the point of no return,” Rignot said in a statement from the NASA Jet Propulsion Laboratory. The study will be published in the journal Geophysical Research Letters.
Basically, six glaciers in that region “hang in a precarious balance,” NASA said in a separate statement. Some parts sit on the land, while other parts float just offshore. As ocean temperatures rise, the glaciers melt from below and thin out. This makes them a bit lighter, and they come up from the land as more seawater flows in below it. It turns into a self-perpetuating loop, one that will not stop until all the ice is gone, the experts said.
Rignot explained the process, and the problem, in detail in the video below as NASA called a hasty press conference to discuss the findings.
And this, though a bit overlapping, contains a few other salient details.
Although the melt may be fairly slow for the rest of this century, it will inevitably accelerate after that, The New York Times reported.
“This is really happening,” said Thomas P. Wagner, a NASA polar ice expert who contributed to the research, told The New York Times. “There’s nothing to stop it now. But you are still limited by the physics of how fast the ice can flow.”
NASA pulled it all together here, again there is some overlap but there are a few other details worth noting. More information is available at NASA's page The 'Unstable' West Antarctic Ice Sheet: A Primer.