The floating portion of Totten Glacier in East Antarctica may be melting from warm sea water swirling beneath it, making it more vulnerable than previously thought to future melting. That’s according to a new study by scientists at the Imperial College London and institutions in Australia, the US, and New Zealand, and published yesterday in Nature. The study’s team found that a part of the Totten Glacier that floats on warm sea water is losing some ice, even while total ice cover in Antarctica continues to expand.
The team studied the history of the glacier’s advances and retreats and speculates that it could contribute 2.9 meters (9.5 feet) to global sea level rise. If the Totten Glacier retreats 300 kilometers (186 miles) inland in the next couple of hundred years, it may release vast quantities of previously frozen water.
The East Antarctic Ice Sheet (EAIS) is relatively stable compared to West Antarctica, which sits on an enormous fault zone. However, the region of the Totten Glacier studied sits on ocean water heated from geothermal activity, which explains the possibility that it could progressively melt.
Antarctica’s ice cover has actually grown in size about 33 percent since satellite tracking began in 1979, making it much more difficult for researchers to gain access to the continent. And then there’s the issue of plate tectonics. West Antarctica sits on an active 3,300-mile-long heat-emitting fault that includes a string of volcanoes, rifts, and hot springs. This fault line is constantly in motion, and this friction generates heat. Most of this geologic activity is buried beneath thousands of feet of snow and ice.
The co-author of the Totten Glacier study, Professor Martin Siegert, says that it could take several hundred years for the Totten Glacier to retreat the necessary 186 miles inland to precipitate melting. The research team studied sedimentary rocks below the glacier and aerial topographic surveys to recreate the history of the Totten Glacier, which they say has experienced large-scale retreats and advances, as indicated by inland bed erosion.
If the Totten Glacier has historically advanced and retreated at various times, and long before man-made carbon dioxide emissions increased globally, it’s logical to suggest that this is a natural phenomenon driven by geologic activity. As mantle heat warms the waters beneath the glacier, it causes the underside melt (see video).