Ice Loss Causes the Earth to Move: Antarctica Changing at a Rapid Rate

It turns out that Antarctica is having an impact on the way the continents are shaped. Scientists have discovered that Earth's mantle under Antarctica is at a lower viscosity and moving at such a rapid rate, it's changing the shape of the land at a rate that can be recorded by GPS.

Previous studies have actually hinted at this movement. Research has shown that the Earth is "rebounding" due to the overlying ice sheet shrinking in response to climate change. This land movement is an instantaneous, elastic response followed by a very slow uplift over thousands of years. Yet now, researchers have found that this movement is far quicker than previously thought.

New GPS data has revealed that the land in the region is actually rising at a rate of 15 mm per year. That's far greater than can be accounted for by the elastic response alone. Instead, it turns out that the mantle below Earth's crust in the Antarctic Peninsula is flowing much faster than expected. This particular flow is probably due to subtle changes in temperature or chemical composition, which means that the flow may respond more quickly to the lightening load hundreds of miles above it as the ice melts.

"You would expect this rebound to happen over thousands of years and instead we have been able to measure it in just over a decade," said Grace Nield, one of the researchers, in a news release. "You can almost see it happening which is just incredible. Because the mantle is 'runnier' below the Northern Antarctic Peninsula it responds much more quickly to what's happening on the surface. So as the glaciers thin and the load in that localized area reduces, the mantle pushes up the crust."

Currently, the researchers have only studied the vertical deformation. However, there are now plans in place to look at the horizontal motion of the ice unloading in order to get a 3D picture of how the Earth is deforming.

"Seeing this sort of deformation of the Earth at such a rate is unprecedented in Antarctica," said Peter Clarke, one of the researchers, in a news release. "What is particularly interesting here is that we can actually see the impact that glacier thinning is having on the rocks 250 miles down."

The findings are published in the journal Earth and Planetary Science Letters.