Why discoveries made by ice-penetrating lasers in the Totten Glacier worry scientists

Flying above the East Antarctic Ice Sheet, researchers say the Totten Glacier has been unstable before, and it may be again soon. 

The University of Texas at Austin
Totten Glacier, East Antarctica's largest outlet of ice, is unstable and has contributed significantly to rising sea levels in the past, according to new research.

The Totten Glacier is the largest glacier in the East Antarctic Ice Sheet, and it is often considered the predictor of the continent’s fate.

However, the glacier is becoming increasingly unstable, say a team of researchers from Texas, Australia, New Zealand, and London in a paper published Thursday in the journal Nature. 

Called the “plug in [an] Antarctic bathtub,” the Totten Glacier holds back more ice than any other glacier in East Antarctica – which is far larger than the West Antarctic Ice Sheet. The Totten Glacier outlet acts as a stopper for the Totten Glacier catchment, which is a “collection basin for ice and snow that flows through the glacier.” Thus, if this region collapses, sea levels could rise by more than 11 feet.

“Totten Glacier’s catchment is covered by nearly two-and-a-half miles of ice, filling a California-sized sub-ice basin that reaches depths of over one mile below sea level,” Donald Blankenship, senior research scientist at the University of Texas at Austin’s Institute for Geophysics and co-author of the paper, said in a press release. “This study shows that this system could have a large impact on sea level in a short period of time.” 

Using ice-penetrating radar, the researchers were able to determine the ice-sheet thickness and historical variation in the sub-ice geology via aircraft. 

“Satellite-based observations indicate that the margin of Totten Glacier may be experiencing greater ice loss than anywhere else in East Antarctica,” the researchers explain in their study. “This, coupled with the presence of low-lying subglacial basins upstream, means the Totten Glacier catchment area could be at risk of substantial ice loss under ocean-warming conditions.”

“This is not the first part of East Antarctica that’s likely to show a multi-meter response to climate change,” Alan Aitken, lead author of the study and a researcher with the University of Western Australia, told The Washington Post. “But it might be the biggest in the end, because it’s continually unstable as you go towards the interior of the continent.”

And the authors say the danger of this rise is backed up with historical evidence. The West Antarctic Ice Sheet has wavered between stability and instability before, so if the conditions warrant, such a shift could occur again.

“By examining the characteristic patters of erosion left by past ice sheet advance and retreat, revealed through mapping the topographic surface and the thickness of sedimentary rocks beneath, this paper demonstrates direct evidence of past changes in the ice sheet in the Totten region,” says Professor Aitken in the release. 

This discovery comes shortly after a team of University of Washington researchers published a study in the journal Geophysical Research Letters last month suggesting a warming Antarctica shouldn’t count on more snowfall.

Because warmer air can hold more moisture, scientists have long predicted that rising temperatures will accompany more snowfall in Antarctica. And while this snow increase will not mitigate dramatic sea level rise over the coming decades, scientists have seen this snowfall side effect as a “potential break” against climate change’s impact, potentially reducing sea level rise by up to one inch in 2100. 

Similar to the study published Thursday on Totten, the UW researchers wanted to determine if this hypothesis was backed up by historical data. 

“It’s not a huge component, but if you live close to sea level, centimeters certainly matter,” lead author T.J. Fudge, a UW postdoctoral researcher in Earth and space sciences, says in a press release. But after studying the West Antarctic Ice Sheet Divide ice core, Dr. Fudge and his colleagues concluded there was no relevant historical data to back up this presumption. “We show that warmer temperatures and snowfall sometimes go together, but often they don’t.”

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