Data on Antarctica’s ice sheets was collected by three satellites: the Gravity Field and Steady State Ocean Circulation Explorer (GOCE) and the twin probes Gravity Recovery and Climate Experiment (GRACE), which work in tandem to map fluctuations in Earth’s gravitational field. As GRACE’s probes orbit the planet, they slow down over regions of lighter mass (which exert less gravitational pull) and speed up over regions of higher mass (which exert greater gravitational pull).
By measuring the two probes distance in relation to each other and their varying speeds, scientists are able to build a map of the Earth’s shifting gravitational field.
Using these satellites, scientists have noticed a shift in the Antarctic region that has coincided with its steady loss of ice. Over a period of three years, most of this loss has been attributed to three glaciers: Pine Island, Thwaites and the Getz Ice Shelf. Between 2009 and 2012, these three glaciers lost 204 billion tons of ice per year.
This report, published in the journal Geophysical Research Letters, dovetails with recent data collected by the CryoSat and ICESat satellites that shows yearly thinning and melting from both Greenland and Antarctic ice sheets at an “unprecedented rate.”
“Since 2009, the volume loss in Greenland has increased by a factor of about two, and the West Antarctic ice sheet by a factor of three,” said Angelika Humbert, who worked on the European Space Agency’s CryoSat mission.
Warmer ocean waters have already placed West Antarctica’s glaciers in a state of “irreversible retreat,” according to NASA. Researchers estimate that if greenhouse gas emissions continue to rise, heightened atmospheric temperatures will warm both air and sea and lead to greater Antarctic melt, potentially raising global ocean levels by up to 14.6 inches.