The Totten Glacier—East Antarctica’s largest outlet of ice—is melting fast and has the potential to raise global sea levels by at least 11 feet (3.5m)
EAST ANTARCTICA—Seafloor troughs may raise global sea levels by melting the base of the Totten Glacier, says a new study conducted by researchers at the University of Texas, NASA and other research organizations.
The Totten Glacier is East Antarctica’s largest outlet of ice to the ocean; approximately 65km long and 30km wide. The glacier, which has the potential to raise global sea levels by at least 11 feet (3.5 m) if completely diminished, has been rapidly thinning for many years. Antarctica’s shrinking mass has long been a matter of interest and study for scientists, however it was believed that the East Antarctica Ice Sheet was relatively stable as it is surrounded by cold water—unlike the West Antarctica Ice Sheet, which looses ice at a rate of more than 150 cubic km per year. In an attempt to understand why the Totten Glacier was continuing to thin, the team of scientists surveyed the area.
Using aircraft equipped with radar alongside other geophysical techniques, the team of scientists measured the thickness of the glacier’s ice, the shape and elevation of the ice, and even the strength of Earth’s gravity and magnetic fields. This enabled the team to map the landscape beneath the glacier and determine the shape of the seafloor; revealing a five km-wide valley running underneath the glacier that is capable of letting warm ocean water reach the ice base.
Thin ice at the margins of ice sheets can float on the ocean, however ice inland is grounded and in contact with the bedrock. The valley allows warm ocean water to flow underneath the region of floating ice: exposing the grounded edge of the glacier to warmer water and leading to melting. Warm water can be found below cooler water in the Antarctic because it is saltier, and therefore heavier.
“It’s only one glacier, but it’s changing now and it is significant for sea levels globally,” announced study co-author Martin Siegert, from Imperial College London.
“The 3.5 m rise may take several centuries to complete, but now the process has started it is likely irreversible. This is another example of how human-induced climate change could be triggering major changes with knock-on impacts that will be felt globally” Siegert added.
“Now we know the ocean is melting ice in an area of the glacier that we thought was totally cut off before,” commented lead author Jamin Greenbaum, from the University of Texa. “Knowing this will improve predictions of ice melt and the timing of future glacier retreat.”
— Antonio Sousa, Correspondent (Antarctica)
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