May 13 - Vast glaciers in West Antarctica seem to be locked in an irreversible thaw linked to global warming that may push up sea levels for centuries, according to scientists. A new study by researchers at NASA's Jet Propulsion Laboratory and the University of California, Irvine, says the glaciers have ''passed the point of no return'' and there is nothing to stop the entire glacial basin from melting into the sea. Rob Muir reports.
According to scientists at NASA, a large sector of the West Antarctic ice sheet has gone into a state of irreversible retreat They say data collected from satellites and other aircraft show six glaciers, includng the Pine Island and Thwaites glaciers, melting into the Amundsen Sea at a rate that lead author Eric Rignot says makes their eventual disappearance inevitable. SOUNDBITE (English) ERIC RIGNOT, GLACIOLOGIST, JET PROPULSION LABORATORY/US IRVINE, SAYING: "We passed the point of no return in this sector and, at this point, it's just a matter of time before these glaciers completely disappear to sea." NASA has turned the data into graphic animation that illustrate the speed of water flowing from each of the glaciers. Rignot says the regions marked in red indicate areas where the flow is increasing every year. SOUNDBITE (English) ERIC RIGNOT, GLACIOLOGIST, JET PROPULSION LABORATORY/US IRVINE, SAYING: "We are seeing in this sector retreates that we don't see anywhere else on earth. They are retreating at rates of about a kilometre per year. That may not seem much to people who are not familar with these glaciers but most of them don't change on that scale." One area of particular concern is the Smith Glacier, Rignot says that between 1996 and 2011 the grounding line where the ice meets the rock below, retreated 35 kilometres at a rate of 2 kilometres per year. The study says this part of Antarctica would be a major contributor to sea level rise in year to come, with the glaciers holding enough ice to raise sea levels by 1.2 meters. Rignot says that while a reduction of green house gas production could slow the warming of the surrounding oceans and the rate of ice melt, the glacial retreat in this part of the Antarctic, appears unstoppable.