Scientists can listen to the splash of calving icebergs to track the crumbling of ice into the sea.

Ice that breaks off from ice shelves and glaciers contributes to sea-level rise. This calving is likely to become more common as the planet warms, but is hard to track because many glaciers are in remote locations.

In the summer of 2016, Oskar Glowacki and Grant Deane at the Scripps Institution of Oceanography in La Jolla, California, placed two underwater microphones in front of the Hansbreen glacier in Svalbard, Norway. They recorded the sound as icebergs broke off from the glacier and collapsed into the water, and observed the calving with time-lapse photography.

An iceberg calving into the sea makes an audible splash. Download MP3

Using this information, the scientists calculated the energy of those splashes and, from that, extrapolated the amount of ice that broke off in each calving event. Underwater microphones at other locations could help researchers to track how much ice is being lost, and how quickly, at glaciers around the world.