London – Antarctica’s Thwaites Glacier, also known as the “doomsday glacier”, is larger than previously thought, triggering concerns of faster melting and accelerating ice flow, researchers say. They were able to take measurements beneath it, with the help of an uncrewed submarine called “Ran” that made its way under the glacier front. Lead author Anna Wahlin, Professor at the University of Gothenburg in Sweden, said using the Ran results, the team’s observations, published in the journal Science Advances, mapped the ocean currents that flow below Thwaites’s floating part. Melting around these pinning points may lead to instability and retreat of the ice shelf. Alastair Graham, from the University of Southern Florida, said: “The channels for warm water to access and attack Thwaites weren’t known to us before the research. Using sonars on the ship, nested with very high-resolution ocean mapping from Ran, we were able to find that there are distinct paths that water takes in and out of the ice shelf cavity, influenced by the geometry of the ocean floor.” Although the amount of ice that melts as a result of the hot water is not much compared to other global freshwater sources, the heat transport has a large effect locally and shows the glacier is not stable over time.