Scientists concerned about climate change are closely monitoring the thickness of polar sea ice. For many years, ice cover has been deemed a significant gauge of global warming’s impact on the Earth. The loss of sea ice in the Arctic and Antarctica could speed up the rate of global warming, leading to the rise of sea levels among other serious consequences, and a new research study based upon data from the European Space Agency’s CryoSat mission shows an unprecedented loss of ice volume.
The European Space Agency (ESA) launched the CryoSat satellite back in April of 2010 to specifically measure the thickness of polar sea ice as well as observe changes in the ice sheets that cover Greenland and Antarctica. Since then, CryoSat has been able to collect 200 million data points across Antarctica and 14.3 million from Greenland. A team from Germany’s Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research analyzed the data to discover how the ice sheets have changed over the last three years.
CryoSat is unique in many ways. Its main instrument is the Synthetic Aperture Interferometric Radar Altimeter or SIRAL. This instrument is the first of its kind to be designed in order to detect tiny variations at the margins of both ice sheets and floating ice. It can also measure sea level with an extraordinary level of accuracy. SIRAL sends out short radar pulses that bounce off the surface of the ice and then determine the height of that ice by measuring the time it takes the signals to return. CryoSat has also been able to orbit the Earth closer to the poles than earlier missions.
The latest data from CryoSat on ice of both Greenland and Antarctica were published in a European Geosciences Union Journal called The Cryosphere along with maps that display the current highs and lows of the ice sheets. These maps cover more square kilometers than previous altimetry models and are extremely accurate. But the new results have scientists worried. The maps show a loss in ice volume at an astonishing rate of 500 cubic kilometers (approximately 120 cubic miles) a year.
The results are troubling because it is the highest loss rate observed since altimetry satellite records began about twenty years ago. Melting sea ice has a major impact on rising sea levels and the ice sheet’s contribution to this increase has doubled since 2009. Greenland’s ice volume loss has increased by a factor of two whereas Antarctica’s loss has increased by a factor of three. On the other hand, the East Antarctic Ice Sheet has been gaining in volume but not enough to compensate for losses on other parts of the continent.
Overall, the project highlights the role that CryoSat has been able to play in taking the observation of ice height to new levels. CryoSat’s SIRAL enabled scientists to monitor the surface of ice better than any other previous system and in regions with more pronounced elevation changes and steep slopes. With CryoSat and other missions like it, there is hope that scientists can better understand the changing nature of sea ice and how it impacts the planet.
“Ice Sheet Highs, Lows and Loss.” European Space Agency. N.p., 20 Aug. 2014. Web. 01 Oct. 2014. <http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat/Ice_sheet_highs_lows_and_loss>.
Helm, V., Humbert, A., and Miller, H.: Elevation and elevation change of Greenland and Antarctica derived from CryoSat-2, The Cryosphere, 8, 1539-1559, doi:10.5194/tc-8-1539-2014, 2014.
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