TECH
13/05/2014 07:14 BST | Updated 13/05/2014 08:59 BST

Antarctic Melting Is Now 'Unstoppable' Says Nasa

Nasa has some bad news: nothing can stop catastrophic melting of the Antarctic glaciers now.

Nothing.

Sorry about that.

According to a new study based on 40 years of satellite and radar observations, the West Antarctic Ice Sheet now appears to be in an "irreversible" state of decline.

There is now "nothing to stop the glaciers in this area from melting into the sea".

Glaciologist and lead author Eric Rignot, of UC Irvine and NASA's Jet Propulsion Laboratory said the area "will be a major contributor to sea level rise in the decades and centuries to come", adding that it could take two centuries or more for the process to come to its horrible, gurgling end.

The glaciers have thinned so much they are now effectively 'floating' above places where they used to sit solidly on land.

"The grounding line is buried under a thousand or more meters of ice, so it is incredibly challenging for a human observer on the ice sheet surface to figure out exactly where the transition is," Rignot said. “This analysis is best done using satellite techniques."

It is thought that these glaciers alone could raise sea levels by 1.2 metres, or 4 feet.

Nasa explains.

"The team used radar observations captured between 1992 and 2011 by the European Earth Remote Sensing (ERS-1 and -2) satellites to map the grounding lines' retreat inland. The satellites use a technique called radar interferometry, which enables scientists to measure very precisely -- within less than a quarter of an inch -- how much Earth's surface is moving. Glaciers move horizontally as they flow downstream, but their floating portions also rise and fall vertically with changes in the tides. Rignot and his team mapped how far inland these vertical motions extend to locate the grounding lines."

The study has now been accepted into the Geophysical Research Letters journal.