An undated handout photo made available by the NASA on 30 January 2019 shows an aerial view on Thwaites Glacier in the Antarctic.

Researchers found a disturbing growth of gaps between ice and bedrock at Thwaites’ bottom big enough to have contained 14 billion tons of ice, and most of that ice melted over the last three years. The cavity was revealed by ice-penetrating radar in NASA’s Operation IceBridge.