Giant hole in Antarctica Thwaites Glacier

Pablo Tucker
February 1, 2019

NASA has made a "disturbing discovery" while surveying the Thwaites Glacier in Antarctica: a massive 1,000-foot (300-meter) tall cavern that's roughly two-thirds the size of Manhattan.

The huge hole - measuring nearly 1,000 feet (300 meters) tall - was found growing at an "explosive rate" at the bottom of a glacier in West Antarctica, said NASA's Jet Propulsion Laboratory in a statement Wednesday. Scientists had long predicted the glacier was not tightly attached to the bedrock underneath it and expected to find some gaps.

Yet the vast size and fast-moving growth rate of the hole in Thwaites was called both "disturbing" and "surprising" by researchers.

For starters, the void is large enough to have once held 15 billion tons (13.6 billion metric tons) of ice, but much of that ice has melted during the past three years, according to NASA.

By observing the undersides of Antarctic glaciers, researchers hope to calculate how fast global sea levels will rise in response to climate change.

Thwaites Glacier plays an instrumental role in the story of rising sea levels and climate change, so there's never been more of a drive to study and understand it. Instead, scientists use satellite or airborne instrument data to observe features that change as a glacier melts, such as its flow speed and surface height.

"Thanks to a new generation of satellites, we can finally see the detail".

Thwaites Glacier is about the size of Florida and now responsible for roughly 4 percent of global sea rise.

While Thwaites is certainly a hard place to reach, a five-year expedition by the International Thwaites Glacier Collaboration to study the glacier will begin this summer.

"We are discovering different mechanisms of retreat", first author of the new paper, JPL radar scientist Pietro Milillo explains. The research has shown that Thwaites Glacier is peeling off from the bedrock beneath it, meaning more of the glacier's base is exposed to warming waters. The glacier has retreated at a steady rate of about 0.4 to 0.5 miles (0.6 to 0.8 km) annually since 1992, the researchers found.

Thwaites Glacier, curiously, isn't melting in a uniform way.

Despite this stable rate of grounding-line retreat, the melting rate on this side of the glacier is extremely high.

Scientists were also able to chart the rate of retreat and ice loss, finding a "complex pattern", where some sectors retreated faster with more melting than others. Co-authors were from the University of California, Irvine; the German Aerospace Center in Munich, Germany; and the University Grenoble Alpes in Grenoble, France.

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