Giant Antarctic rift fuelling ice loss

Researchers from the UK have discovered a mile deep rift in Antarctica that is speeding melting in the region. The Ferrigno rift, as it is known, lies close to the Pine Island glacier and is one of the most remote parts of the continent, only visited a handful of times.

The team from the British Antarctic survey visited the region two years ago with ground penetrating radar to study the area. "What we found is that lying beneath the ice there is a large valley, parts of which are approximately a mile deeper than the surrounding landscape," said Dr Bingham from Aberdeen University.

"If you stripped away all of the ice here today, you'd see a feature every bit as dramatic as the huge rift valleys you see in Africa and in size as significant as the [US] Grand Canyon. This is at odds with the flat ice surface that we were driving across - without these measurements we would never have known it was there."

The crucial effect the rift plays is to channel the relatively warm sea water into the region under the ice, lubricating the ice and making it flow more quickly into the sea. "We know that the ice loss from the West Antarctic Ice Sheet is governed by delivery of warm water, and that the warm water is coming along channels that were previously scoured by glaciers," said Prof David Vaughan, speaking to the BBC. "So the geology and the present rate of ice loss are intricately linked, and they feed back - if you have fast-flowing ice, that delivers ice to the edge where it can be impacted by warm water, and warm water makes the ice flow faster".

Currently the West Antarctic is contributing around ten percent to overall sea level rise, but it is difficult to predict how the region will behave as global warming continues to occur. The Pine Island Glacier for example, seems set to calve a 900 square kilometer iceberg imminently.

The larger East Antarctic ice sheet is not showing the same signs of break up, but the threat of sea level rise from Greenland, mountain glaciers and the West Antarctic is considerable, with predictions of 3 or 4 feet increases by the end of the century, which would cause havoc for many coastal cities.