Research published last week by the American Geophysical Union documents a chaotic, low-frequency hum across the Ross Ice Shelf — a platform the size of France that floats off the coast of West Antarctica. The pitches are caused by wind striking snow dunes, and it’s an eerie sort of song. But, the researchers argue, it’s also an early warning sign for one of the nightmare scenarios in climate change science: the disintegration of Antarctica’s largest ice shelf, and consequent slide of glaciers into the ocean. The song slows down when snow begins to melt in the ice shelf’s top layers.