They call it the “Doomsday Glacier” due to its size and ecological relevance: It's estimated that if the 258,000 km³ of ice it has above the waterline were to melt, sea level could rise by 25.5 inches. Its real name, however, is the Thwaites Glacier, and now we know there's main threat looming over it.
Warm water. A recent study has made an alarming discovery, finding that warm, high-pressure seawater has filtered through to the base of Antarctica’s Thwaites Glacier.
What makes it alarming is that it could mean that the rate at which the glacier is melting is actually greater than scientists thought. “The worry is that we are underestimating the speed that the glacier is changing, which would be devastating for coastal communities around the world,” Christine Dow, the co-author of the study, said in a press release.
An enormous glacier. This is also an alarming find due to the size of this glacier. Its basin measures 74,000 square miles (192,000 square kilometers), or about the size of Senegal. It's located on the northern coast of West Antarctica, and its volume is 483,000 km³.
Part of this volume is submerged, but almost half is above the surface. This means that if this glacier’s snow and ice were to melt and flow into the ocean, the sea level would increase by 25 inches, according to estimates by the International Thwaites Glacier Collaboration.
Vigorous melting. The water infiltrations detected in the glacier are bad news due to the “vigorous melting”–in the words of the team responsible for the work–that they're causing.
These infiltrations are caused by the effect of the tides on the glacier ice. These tides push large amounts of warm water underneath the ice, which causes the glacier ice to melt and release freshwater. It mixes with the water from the glacier, which is less salty. In this way, a network of underwater channels is created in the ice, one that grows progressively with each tide.
Looking beneath the mantle. We've known about the importance of this glacier for years. If news about it took too long to arrive, it is because studying it is quite complicated—partly due to its size. In this case, the team responsible for the discovery used data from the InSAR (Interferometric Synthetic Aperture Radar).
The InSAR is one of the sensors on board Finland’s ICEYE satellites, which pass frequently over the poles. Because of this sampling frequency, the team was able to monitor the glacier with high-resolution data between March and June of last year. The details of the process and its results were published in the journal Proceedings of the National Academy of Sciences.
25.5 inches, and counting. The problem could be even more serious if we take into account two things. On one hand, the disappearance of the Thwaites Glacier could cause more than the arrival of its huge volume of ice and snow to the ocean. The glacier also acts as a sort of “plug” to the surrounding masses of Antarctic ice; if the glacier melts, these masses will probably reach the sea, too.
The second problem is that the phenomenon that has been observed there could also be taking place in other polar glaciers in the world besides Antarctica, such as Greenland. These are the two regions where the ice rests on land, which, in case of melting, would translate into a hypothetical net positive contribution to the sea level.
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