Terry Wilson: The fundamental control of sea level is how much ice is locked up in the polar ice sheets. So if they are indeed losing their mass, that is going into the oceans and causing sea level to rise which is of great societal relevance right now, particularly given the evidence for global warming.
That’s Earth scientist Terry Wilson. Dr. Wilson is part of a research project called POLENET. The project uses GPS and seismic sensors to record the movement of ice and bedrock in Antarctica, the continent of the south pole. Wilson explained why it’s important to monitor the solid bedrock, beneath Antarctic ice – and not just the on-going melting of the ice itself.
Terry Wilson: It’s kind of simple conceptually. If you pile a load of ice on the surface of the earth, even though most people think of it as solid, in fact it bends under the weight of the ice. if you take the ice off the top, it bends back up, which is what we call ‘rebound.’
How much the bedrock rebounds, said Wilson, can help determine how much ice there was before. Wilson said this technique can help determine how much ice has been lost.
Terry Wilson: It’s very significant to work this out now, so we can get a better handle on predicting future behavior of the ice sheet.
The GPS sensors record these movements from space satellites, and seismic sensors record them directly from ground, at the South Pole. The two POLENET monitoring systems work together to measure this movement of the Earth, which is actually very slight – mere millimeters.
Terry Wilson: It’s only through correcting for what the solid earth is doing that our satellite sensors can actually accurately estimate the ice mass change.
Our thanks to:
Ohio State University
Beth Lebwohl researches, writes and helps produce science content in audio and video formats for EarthSky. She is one of the authors on EarthSky.org, a script-writer for our podcasts, and helps host our English science podcasts in 90-second, 8-minute and 22-minute formats. Beth came to EarthSky in 2006 from the American Museum of Natural History's Department of Astrophysics, where she was surrounded by some of the greatest telescope-building, equation-wielding, code-writing physicists of our time. And they made her think . . . this science thing . . . it's pretty cool.