Thwaites Glacier in Antarctica developed a cavity almost as large as Manhattan


The Thwaites Glacier, the largest outflow channel of the vulnerable West Antarctic Ice Sheet, now has a big subterranean hole.

The hole, which is nearly 1,000 feet tall, was seen during the space agency's study of the disintegrating Thwaites Glacier in West Antarctica, NASA said Wednesday.

The melting of the Thwaites Glacier, which is the approximately the size of Florida, is already behind about four percent of global sea rise, according to the Jet Propulsion Laboratory. Scientists expected to find some relatively small gaps between the glacier and bedrock, but were unsettled by the 1,000-foot deep cavity the mission revealed.

Thwaites glacier in western Antarctica.

"We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it", said Eric Rignot, one of the co-authors of the study. "Thanks to a new generation of satellites, we can finally see the detail", he said.

Scientists used a combination of ice-penetrating radar flown on NASA planes and European satellite data to capture what's going on.

These very high-resolution data can be processed by a technique called radar interferometry to reveal how the ground surface below has moved between images.

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"[The size of] a cavity under a glacier plays an important role in melting", the study's lead author, Pietro Milillo of NASA's Jet Propulsion Laboratory, said in a news release about the study.

"As more heat and water get under the glacier, it melts faster".

It also backstops other glaciers capable to raising sea levels another 2.4m. The International Thwaites Glacier Collaboration is a joint project between the U.S. National Science Foundation and the British National Environmental Research Council with the aim of getting a better understanding of the glacier and how it will respond to climate change in the future.

A large hole under an Antarctic glacier is a sign of rapid decay that could lead to dramatic sea level rise, a study says.

From 1992 to 2011, the centre of the Thwaites grounding line retreated by almost 14 kilometres. For instance, the 100-mile-long (160 kilometers) glacier front has different rates of retreat in its grounding line (where the sea ice meets the ocean's bedrock) depending on where you look.

These results highlighted that ice-ocean interactions were more complex than previously understood. Hopefully, the upcoming global collaboration will help researchers piece together the different systems at work under and around the glacier, the researchers said.