A massive cavity that’s two-thirds as large as Manhattan is expanding below an Antarctic glacier, according to a “disturbing” discovery revealed through a recent NASA-led study.
Researchers, who have long suspected a cavity between the Thwaites Glacier in West Antarctica and the underlying bedrock, used ice-penetrating radar and new satellites capable of high-resolution data to study the glacier more closely. They found a cavity 1,000-feet tall that was “big enough to have contained 14 billion tons of ice—and most of that ice melted over the last three years.”
“[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.”
JPL said that the findings “highlight the need for detailed observations of Antarctic glaciers’ undersides in calculating how fast global sea levels will rise in response to climate change.”
The Thwaites Glacier, which is about the size of Florida, has been responsible for about 4% of the rise in sea levels so far, still holds enough ice to raise the world ocean a little over 2 feet upon melting. It could also lead to melting in neighboring glaciers that could add another 8 feet to sea levels if they completely melted, JPL said.
Other recent studies have shown that sea levels are already rising as fast as they have in 2,800 years, and that oceans could rise twice as much this century as scientists had previously anticipated. Most of the melting so far has come from Arctic ice, which produces the equivalent of 14,000 tons per second of water into the oceans.