July 25, 2012

Culprit Behind Ice Loss In West Antarctica Revealed

Lee Rannals for - Your Universe Online

Scientists believe they have discovered a hidden rift valley that may be contributing to ice loss in West Antarctica.

University of Aberdeen and British Antarctic Survey (BAS) experts made the discovery below Ferrigno Ice Stream, which is a very remote region that has only been visited once before.

The team has reveled that the ice-filled ancient rift basin is connected to the warming ocean, which impacts ice flow and loss.

The West Antarctic Ice Sheet is considered to be of great scientific interest and societal importance because it is losing ice faster than any other part of Antarctica. The area even has some glaciers that are shrinking by more than three feet per year.

If scientists can understand the process that influence ice loss from West Antarctica, then it could help improve predictions of its future behavior.

Dr. Robert Bingham, lead author of the study published in Nature, discovered the rift valley during three months of fieldwork with BAS in 2010.

"Over the last 20 years we have used satellites to monitor ice losses from Antarctica, and we have witnessed consistent and substantial ice losses from around much of its coastline," Bingham said in a press release. "For some of the glaciers, including Ferrigno Ice Stream, the losses are especially pronounced, and, to understand why, we needed to acquire data about conditions beneath the ice surface."

The team gathered the data using an ice-penetrating radar system, which arrived by way of a skidoo that was driven across the flat ice surface over 1,500 miles.

"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," Bingham said. "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 Grand Canyon."

He said that is important that the valley aligns perfectly with the recording of ice-surface lowering and ice loss that they witnessed with satellite observations over the last 20 years.

"The newly discovered Ferrigno Rift is part of a huge and yet poorly understood rift system that lies beneath the West Antarctic Ice Sheet," Co-author and geophysicist Dr. Fausto Ferraccioli from British Antarctic Survey said in a press release. "What this study shows is that this ancient rift basin, and the others discovered under the ice that connect to the warming ocean can influence contemporary ice flow and may exacerbate ice losses by steering coastal changes further inland."

Professor David Vaughan, from British Antarctic Survey and leader of Ice2sea, said that the thinning ice in West Antarctica is contributing to about 10 percent of the global sea level rise.

"It's important to understand this hot spot of change so we can make more accurate predictions for future sea level rise," Vaughan said in the press release.

The research is part of the British Antarctic Survey Icesheet Program, which examines the role of ice sheets in the Earth System, as well as the processes that control ice-sheet change.

The program monitors current change, and sets it into context with the past, which allows for more accurate projections for increases in global sea level.