Infrastructure protectionLoss of West Antarctic glacier unstoppable, contributing significantly to sea level rise
A rapidly melting section of the West Antarctic Ice Sheet appears to be in irreversible decline, with nothing to stop the entire glacial basin from disappearing into the sea, according to researchers at UC Irvine and NASA. The new study presents multiple lines of evidence — incorporating forty years of observations — that six massive glaciers in the Amundsen Sea sector “have passed the point of no return.” The volume of melted ice would be enough to raise global sea level by four feet.
A rapidly melting section of the West Antarctic Ice Sheet appears to be in irreversible decline, with nothing to stop the entire glacial basin from disappearing into the sea, according to researchers at UC Irvine and NASA.
The new study presents multiple lines of evidence — incorporating forty years of observations — that six massive glaciers in the Amundsen Sea sector “have passed the point of no return,” according to glaciologist Eric Rignot, a UC Irvine Earth system science professor who is also with NASA’s Jet Propulsion Laboratory. The new study has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.
A UCIrvine release reports that these glaciers already contribute significantly to sea level rise, releasing as much ice into the ocean each year as the entire Greenland Ice Sheet does. They contain enough ice to boost the global sea level by four feet (1.2 meters) and are melting faster than most scientists had expected. Rignot said the findings will require that current predictions of sea level rise be revised upward.
“This sector will be a major contributor to sea level rise in the decades and centuries to come,” Rignot said. “A conservative estimate is that it could take several centuries for all of the ice to flow into the sea.”
Three major lines of evidence point to the glaciers’ eventual demise: changes in their flow speeds, how much of each glacier floats on seawater, and the slope and depth below sea level of the terrain they are flowing over. In a paper published last month, the research group showed that the speed at which the glaciers are moving has accelerated steadily for four decades, increasing the amount of ice draining from them by 77 percent from 1973 to 2013. This new study focuses on the other two lines of evidence.
The West Antarctic glaciers flow out from land over the ocean, with their front edges afloat.
The point at which they lose contact with land is called the grounding line. Virtually all glacial melting occurs on the undersides of their floating sections — beyond the grounding line.
