President Donald Trump unleashed yet another in a string of colorfully misguided tweets deriding global warming on Jan. 28, saying in part: “…windchill temperatures are reaching minus 60 degrees, the coldest ever recorded…What the hell is going on with Global Warming? Please come back fast, we need you!”

Just two days later, JPL-NASA announced troubling global warming news in Antarctica: a huge cavity two-thirds the size of Manhattan and almost 1,000 feet tall is growing inside the Thwaites Glacier in West Antarctica.

The glacier was named after Fredrik T. Thwaites (1883-1961), a glacial geologist, geomorphologist and a professor emeritus at the University of Wisconsin–Madison. Thwaites Glacier drains into West Antarctica’s Amundsen Sea. 

“We have suspected for years that Thwaites was not tightly attached to the bedrock beneath it,” said Eric Rignot of UC Irvine, and NASA’s Jet Propulsion Laboratory in Pasadena. Yet the size of the newfound hole surprised researchers and suggests that 14 billion tons of ice has melted away — most of it in the last three years. 

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

The Thwaites Glacier is nearly the size of Florida and researchers estimate that its meltdown is responsible for approximately 4 percent of global sea level rise. The glacier holds enough ice to raise the world ocean a little over 2 feet and if it affects neighboring glaciers, sea levels could rise an additional 8 feet if all the ice were lost.

The cavity was revealed by ice-penetrating radar in NASA’s Operation IceBridge, an airborne campaign that began in 2010 and studies connections between the Earth’s polar regions and the global climate. The researchers also used data from a constellation of Italian and German spaceborne synthetic aperture radars. These very high-resolution data are processed by a technique called radar interferometry to reveal how the ground surface below has moved between images.

The US National Science Foundation and British National Environmental Research Council are mounting a five-year field project to answer the most critical questions about Thwaites.