Gravity itself is the newest casualty in the war on global warming. So much ice has melted in Antarctica that the gravitational field in the region was altered, new data from the European Space Agency shows.
The ESA's GOCE (Gravity Field and Steady-State Ocean Circulation Explorer) satellite, which has spent four years orbiting the Earth and measuring the gravitational fields, is able to record Earth's gravity in better detail than any other satellite to date. The satellite showed a significant dip in the gravity over West Antarctica. ESA scientists announced on Friday, Sept. 26, that they could see a change in West Antarctica's gravitational field over the past four years, likely caused by melting ice.
Scientists from Germany, the Netherlands and the U.S. studied the imaging of the gravitational fields in Antarctica from 2009 to 2012. The scientists found that the imaging showed a decrease in gravity over that time period that correlated to a decrease in ice over that time. The GOCE satellite was not designed to show changes over a period of time, and the satellite was not testing specifically for the effects of global warming on the gravity, so this is an unexpected find from the satellite.
The ESA posted a video of the gravity change occurring, so that people can better visualize the effects of the melting ice on the gravitational fields. The researchers were able to combine the data from the GOCE mission with data from GRACE (Gravity Recovery and Climate Experiment), a collaboration between NASA and Germany. The GRACE mission shows change in gravity over time, but in much lower resolution. By combining the information collected by both missions, the researchers were able to create a fairly accurate picture of gravitational change over the past three years.
This study adds to the mounting evidence that global warming and the collapse of the ice sheets in Antarctica are having huge, fundamental effects on the Earth. This May, scientists announced that the collapse of the glaciers in West Antarctica is likely irreversible at this point, meaning the oceans will almost certainly rise by several meters in the next few years.
More research needs to be done to assess the gravitational fields in the rest of Antarctica.
"We are now working in an interdisciplinary team to extend the analysis of GOCE's data to all of Antarctica. This will help us gain further comparison with results from CryoSat for an even more reliable picture of actual changes in ice mass," said Johannes Bouman, one of the researchers from the German Geodetic Research Institute.
