The bedrock below the West Antarctic Ice Sheet (WAIS) is rising more rapidly than expected, according to an international team of researchers. The unexpected discovery has several implications for the future of the Antarctic continent.
The fast rate of the rising earth beneath the icy continent, which is twice the size of Australia, could mean increased stability for the ice sheet in the face of catastrophic collapse due to ice loss. Scientifically known as tectonic uplift, the rise also implies that up to 10 percent more ice has melted off the (WAIS) than previously assumed.
Because of its lack of civilization, the Antarctic is defined entirely by its geography. The marine portion of the WAIS is known as the Amundsen Sea Embayment (ASE), and the ASE is so massive that it by itself it accounts for 25 percent of all water estimated from melting ice on Earth. In one year, the ASE loses enough water to cover an area the size of Denmark (43.000 square km) with just over 9 feet (2.8 meters) of water.
The ASE also holds enough ice to raise the global sea level by almost 4 feet (1.2 meters)
“The large amount of water stored in Antarctica has implications for the whole planet, but especially for northern Europe, because of a combination of gravitational effects, surprisingly, the ice lost in Antarctica mostly raises the sea level here, in northern Europe. In contrast, the ice lost in Greenland has no effect here, but it raises the sea level in the southern hemisphere and further destabilizes the WAIS,” says postdoctoral researcher Valentina R. Barletta at DTU Space, the National Space Institute at the Technical University of Denmark, the leading author of the new study in a press statement.
Researchers from the Ohio State University 6 GPS stations on rock outcrops around the ASE, from the POLNET-ANET array, to measure the land’s rise. The uplift rate measured out to 41 millimeters (1.6 inches) a year. For comparison, uplift rates in Alaska and Iceland are 20-30 milllimeters a year and are widely seen as rapid.
“The rate of uplift we found is unusual and very surprising. It’s a game changer,” says Terry Wilson, another lead author of the new study.
The rapid uplift around the ASE suggests that Antaractica’s mantle—the area underneath it’s outer layer of crust— is hotter and more fluid than expected. That would mean that it reacts extremely quickly to the weight of ice being removed.
“The physical geography of Antarctica is very complex. We found some potentially positive feedbacks in this area, but other areas could be different and have negative feedbacks instead,” Wilson says.
While rapid uplift shows the effects of global warming, the scientists say, it could also offer a hinderance of sorts. Dealing with a scenario of moderate climate change, modeling shows that enough uplift could even theoretically prevent a WAIS collapse. However, under a model of severe global warming no amount of uplift could save the ice sheet.
Previously published by: Popular Mechanics USA