Antarctic glacier's slow collapse unstoppable, scientists say

It appears that there is no way to stop the Antarctic glaciers from melting into the sea, according to two studies released Monday. NASA glaciologist Eric Rignot said the glaciers "have passed the point of no return."

If the melting continues, it puts neighboring sections of the ice sheets at risk and could lead the sea level to rise 10 feet or more. It would take many decades, or even centuries, for the impact to be felt, but scientists say it puts future generations at risk.

"This sector will be a major contributor to sea level rise in the decades and centuries to come," Rignot said in the NASA press release. "A conservative estimate is it could take several centuries for all of the ice to flow into the sea."

"This is really happening," NASA's Thomas P. Wagner 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."

Comprised of scientists from NASA and the UC Irvine, the first study incorporated 40 years of evidence, concluding that man-made climate change and increasing global temperatures are the primary factors in the decline of the ice sheets. Led by Rignot, the study will be published in the journal Geophysical Research Letters.

Rignot's team used satellite and air measurements to show that six glaciers in the Amundsen Sea have started retreating at a more accelerated rate in recent decades. Mapping the terrain beneath the ice did not reveal any mountains or other land masses that could slow the melting.

If these six glaciers continue to retreat at the current rates, they could lead to a four-foot rise in sea level within the next 200 years. But overall sea level rise could be even greater, because the melting of these six glaciers will likely destabilize neighboring sections of the ice sheet.

"The collapse of this sector of West Antarctica appears to be unstoppable," he said. "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."

The second study, conducted separately and published in the journal Science, found that the Thwaites glacier will collapse, likely within the next 200 years. Scientists consider Thwaites to be one of the most important Antarctic glaciers. It is being eroded by warm ocean temperatures, and lead author Ian Joughin said there is "no stabilization mechanism" available. Any efforts would be "too little, too late."

The combined findings of the study support the 1978 prediction of John H. Mercer, an Ohio State University glaciologist who said greenhouse gas emission posted "a threat of disaster," according to the Times. Though criticized at the time, his predictions are becoming reality.

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    Danielle Elliot is a freelance science editor and reporter for CBS News. She holds an M.A. in science and health journalism from Columbia University and a B.A. in broadcast journalism from the University of Maryland. Follow her on Twitter - @daniellelliot.

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