Satellite imagery can now help scientists determine the amount of ice lost from Antarctica by presenting exact measurements of the gravity of the Earth. European Space Agency’s latest the Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) mission revealed that melting of ice sheets has caused deviation in the planet’s gravitational norm.
It has been long known that Antarctica’s ice sheets are melting due to increased temperatures, but the effects these melts have on our planet are far from being fully identified. To make it more complicated, the harsh and very difficult to access environment, has prevented scientists from studying the consequences from ice melts, but it has also pushed these teams to explore new and more advanced techniques.
The European Space Agency is one organization that has provided scientists with various high-tech equipment and gadgets, which allow precise and vast satellite observations over areas, where humans may never be able to reach. In the light of recent warnings about the influence of climate change and the harsh targets that governments have set, the saying “if you can’t measure it, you can’t manage it” is becoming the main driving force of the space agency.
One of the first instruments sent to space by ESA, which provided detailed estimates on Antarctica’s ice melts, was the altimeter on board of the satellite CryoSat. Thanks to the complete dataset that the instrument provided, scientists were able to estimate the precise rate of melting of the West Antarctic Ice Sheet. They warned that since 2009, the speed of melting has risen by a factor of three, while for each year between 2011 and 2014, it was estimated that the volume of the whole of Antarctica reduced by 125 cubic kilometres.
The latest mission of ESA, the GOCE satellite, has revealed something else that scientists did not know until now. It seems, melting of ice not only causes rise in sea level, but also changes the gravity of our planet. It is generally accepted that gravity has a value of 9.78 m/s², but this is only an average. A team of scientists from the German Geodetic Research Institute, Delft University of Technology in the Netherlands, the Jet Propulsion Lab in USA and the Technical University of Munich in Germany, were able to show that loss of ice, can cause shifts in gravitational force (see video here).
The findings are still preliminary, yet show an incredible breakthrough, which was not known before. Precise measurements of gravity, and respectfully changes in the values, can serve as an indicator of the speed of ice melts, and therefore show if measures to tackle climate change do indeed have an effect.
Image (c) ESA