The Thwaites Glacier, also known as the “Last Judgment Glacier”, was analyzed from below for the first time thanks to the submarine Ran. The submersible measured, among other things, the strength, temperature, salinity and oxygen content of the ocean currents that pass under Thwaites. And the result is worrying since it can melt faster than researchers imagined due to hot and salty ocean currents that are passing below the site.

The location and shape of the glacier exacerbates this problem. Thwaites is in an area usually blocked by thick sea ice and many icebergs, in addition to being far from research stations.


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According to Anna Wåhlin, professor of oceanography at the University of Gothenburg, Sweden, and lead author of the new study published in Science Advances, the level of tue global warming is affected by the amount of ice on Earth and the biggest uncertainty in forecasts is the future evolution of the West Antarctic ice sheet. "These were the first measurements taken under the Thwaites glacier," she said.

“This was Ran's first adventure in the polar regions and his exploration of the waters under the ice shelf was much more successful than we dared hope. We plan to develop these exciting discoveries with new missions under the ice next year, ”added Karen Heywood, a professor at the University of East Anglia in England.

Ran submarine. Credits: Filip Stedt
Ran submarine. Credits: Filip Stedt

Why “Glacier of the Last Judgment”?

Located in West Antarctica, Thwaites is considered one of the most vulnerable to the effects of warming. It is about 120 km², almost the same size as the United Kingdom, and accounts for 4% of the rise in sea level in the world each year.

The estimate is that the collapse of Thwaites could raise sea levels by more than half a meter. Added to the other glaciers that are grouped with the “Final Judgment Glacier” and thus do not slide into the ocean, the elevation can reach three meters.

“The hot water channels to access and attack Thwaites were not known to us before the survey. Using sonar on the ship, nested with high-resolution oceanic mapping of the submarine Ran, we were able to discover that there are different paths for water to enter and exit the ice shelf cavity, influenced by the geometry of the ocean floor, ”explained Dr. Alastair Graham , from the University of Southern Florida, in the United States.

Thwaites Glacier. Credits: University of Gothenburg
Thwaites Glacier. Credits: University of Gothenburg

“This work highlights how and where hot water affects the Thwaites glacier is influenced by the shape of the seabed and the base of the ice shelf, as well as the properties of the water itself. The successful integration of new seabed survey data and observations of water properties from Ran missions shows the benefits of a multidisciplinary ethos within the Thwaites Glacier International Collaboration, ”added Dr Rob Larter of the British Antarctic Survey in England.

“The good news is that we are now, for the first time, collecting data necessary to model the dynamics of the Thwaites glacier. This data will help us to better calculate the melting of the ice in the future. With the help of new technologies, we can improve the models and reduce the great uncertainty that now prevails around global variations in sea level ”, concludes Wåhlin.

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