According to the latest data collected by the NASA Ice, Cloud, and land Elevation Satellite (ICESat) spacecraft, it would appear that warm ocean currents attacking the underbelly of sea-based ice sheets are the primary driver of ice loss in the Antarctic. The currents are made warmer by climate change.
The Southern Continent is basically under attack from both underneath and above. Warm water and air currents sweep above and below it, rendering its ices unstable, and more prone to thawing and breaking loose from the continent.
What the ICESat data demonstrate conclusively is that warm oceanic currents are the dominant driver of ice loss throughout Antarctica. The investigation was carried out by an international collaboration of researchers, and was published in the April 25 online issue of the top scientific journal Nature.
The ultimate goal of such studies is to enable climatologists to develop reliable projections of future sea level rise. Antarctica and Greenland hold vast amounts of land-based ice, which has the potential to drive sea levels up by tens of feet within a very short time.
Experts have been trying to model the effects of global warming on these critical ice sheets for a long time, but uncertainties still plague their simulations. The new investigation adds other pieces to the puzzle, by allowing scientists to fine-tune their models further.
“We can lose an awful lot of ice to the sea without ever having summers warm enough to make the snow on top of the glaciers melt. The oceans can do all the work from below,” Hamish Pritchard says.
The expert, who holds an appointment with the British Antarctic Survey (BAS), in Cambridge, the United Kingdom, was also the lead author of the Nature paper. The research shows that 20 of 54 ice sheets in the study are being melted by warm ocean currents acting from below.
“This study demonstrates the power of space-based, laser altimetry for understanding Earth processes,” NASA
Headquarters cryosphere program scientist Tom Wagner explains.
“Coupled with NASA's portfolio of other ice sheet research using data from our GRACE mission, satellite radars and aircraft, we get a comprehensive view of ice sheet change that improves estimates of sea level rise,” he concludes.