Totten Glacier is East Antarctica's largest and most rapidly thinning outlet of ice to the ocean, but there was no evidence that it could compromise coastal ice — until now.
By flying a handful of research flights over East Antarctica, taking a variety of measurements, like the ice's thickness, scientists from Researchers at the University of Texas at Austin's Institute for Geophysics (UTIG) have discovered two seafloor gateways that are hastily melting Totten Glacier. The threat to rising global sea levels was even worse than they had previously thought.
The research was published today in Nature Geoscience.
"We now know there are avenues for the warmest waters in East Antarctica to access the most sensitive areas of Totten Glacier," said UTIG Ph.D. candidate and lead author Jamin Greenbaum, in a press release.
This is concerning because the ice that flows through the Totten Glacier alone is enough to raise global sea levels by a minimum of 11 feet — equivalent to the contribution of the West Antarctic Ice Sheet if it were to completely disappear.
If the process continues at its current speed, its effects will soon be irreversible.
The deeper of the two gateways the UTIG team found was a three-mile-wide seafloor valley, extending from the ocean to beneath Totten Glacier. This discovery took the scientists by surprise, as previous satellite analyses had indicated that the ice above this valley was resting on solid ground.
In some areas of the ocean around Antarctica, warm water can be found below cooler water if it is saltier and therefore heavier than the shallower water. As a result, seafloor valleys that connect this deep, warm water to the coast can especially erode glaciers.
This phenomenon is already well-documented in West Antarctica, but these findings reveal that East Antarctica is just as vulnerable.
"Now we know the ocean is melting ice in an area of the glacier that we thought was totally cut off before," Greenbaum said. "Knowing this will improve predictions of ice melt and the timing of future glacier retreat."