City-Sized 1,000-Foot Deep Cavity Found in Glacier, Warns NASA, Signaling 'Rapid Decay' of Antarctic Ice

NASA scientists were startled when a recent exploratory mission revealed a huge and rapidly-growing cavity on the underside of one of Antaractica’s glaciers—signaling that the ice mass has been melting much faster than experts realized.

The cavity is two-thirds the size of Manhattan—large enough to have contained about 14 billion tons of ice before it melted, according to a report that was published in Science Advances on Thursday.

Much of that ice disappeared at an “explosive rate,” scientists reported—likely melting only in the last three years.

“The size of a cavity under a glacier plays an important role in melting,” lead author Pietro Milillo said in a statement. “As more heat and water get under the glacier, it melts faster.”

The agency’s Jet Propulsion Laboratory used ice-penetrating radar to explore the area beneath the Thwaites Glacier in West Antarctica, often called “one of the world’s most dangerous glaciers” because its melting could significantly contribute to sea level rise. 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.