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Thwaites Glacier in Antarctica

Researchers have discovered a cavity the size of the Eiffel Tower growing under the Thwaites Glacier. Image: NASA/OIB/Jeremy Harbeck


The Inertia

According to new research from NASA, something frightening is happing to an enormous glacier in West Antarctica. A large cavity has appeared at the bottom of it, which has scientists worried. Large is an understatement—NASA reported that it’s two-thirds the area of Manhattan and almost 1,000 feet tall.

Thwaites Glacier is no ordinary glacier. At about the size of Florida, it holds enough ice to raise the level of the sea around the world nearly three feet. It also serves as a backstop to glaciers behind it, which, if they were to slide into the sea, would raise the seas by about eight feet.

Over the last decade or so, however, Thwaites has lost a lot of weight, just like many others in the neighborhood. In July of 2017, for example, an iceberg weighing around a trillion tons was created when a massive chunk of the Larsen Ice Shelf.

The cavity at the bottom of Thwaites Glacier isn’t a small one, and it will only get bigger. “[The size of] a cavity under a glacier plays an important role in melting,” study leader Pietro Milillo of NASA’s Jet Propulsion Lab (JPL) said in a statement. “As more heat and water get under the glacier, it melts faster.” The cavity is big enough to hold some 14 billion tons of ice.

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Thwaites Glacier cavity

Changes in surface height at Thwaites Glacier’s grounding line, 2011 to 2017, with sinking areas in red and rising areas in blue. The growing cavity (red mass, center) caused the greatest sinking. The mottled area (bottom left) is the site of extensive calving. Contours show bedrock topography. Credit: NASA/JPL-Caltech

The crack was discovered when a team of NASA researchers from Operation IceBridge used satellites and planes to look deep into the ice. IceBridge started back in 2010, and “studies connections between the polar regions and the global climate.”

What they found was that, along with the cavity, “Thwaites Glacier is peeling off from the bedrock beneath it, meaning more of the glacier’s base is exposed to warming waters.”

According to Eric Rignot, a Professor of Earth system science at the University of California, Irvine, and the principal scientist for the Radar Science and Engineering Section at NASA’s Jet Propulsion Laboratory, scientists have long suspected that Thwaites might be on shaky ground. “We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it,” he said in a release. “Thanks to a new generation of satellites, we can finally see the detail…Understanding the details of how the ocean melts away this glacier is essential to project its impact on sea level rise in the coming decades.”

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