The West Antarctic Ice Sheet. (Photo: AP Photo/NASA)
According to new research from NASA and the University of California, the West Antarctic Ice Sheet has reached the point of no return and has begun an unstoppable process of melting. The sheet constitutes about 10 per cent of the continent's land ice volume — that's about 2.2 million cubic kiliometres of ice.
The research focused on a group of six glaciers that make up the part of the West Antarctic Ice Sheet on the Amunden Sea. Scientists used data collected over the past 40 years to measure the changes in the glaciers. The study showed that the glaciers were melting quickly, being eroded from below by warming ocean water. The glaciers are now precariously unstable. What's especially frightening is that researchers didn't find anything that might slow down the glaciers' retreat — there are no mountains, hills, or any other natural blockages. If the glaciers were to continue melting and crash into the ocean, it's feared that they could raise sea levels by 1.2 metres (or in an absolute worst-case scenario, as much as 4.7 metres)— a potentially disastrous occurrence for many coastal cities around the world.
"The system is in sort of a chain reaction that is unstoppable," said glaciologist Eric Rignot, chief author of the NASA study in the journal Geophysical Research Letters. "Every process in this reaction is feeding the next one."
You can get a good sense of how this is happening in this video released by NASA:
Just how soon could this happen? A second study by researchers at the University of Washington, which was released in conjunction with the NASA paper and published in the journal Science, suggests it could take as few as 200 years (which isn't nearly as long as it sounds), or as many as 1,000.
Researchers noted that the 800-year discrepancy depends greatly on us. Reducing emissions and other drastic action on climate change could help to slow down the melting — but they say it's too late to stop it.
"The system really is going down," said Rignot. "How fast it is going to go is critical."