By combining 25 years of ESA satellite data, scientists have discovered that warming ocean waters have caused the ice to thin so rapidly that 24% of the glacier ice in West Antarctica is now affected. A paper published in Geophysical Research Letters describes how the UK Centre for Polar Observation and Modelling used over 800 million measurements of Antarctic ice sheet height recorded by radar altimeter instruments on ESA’s ERS-1, ERS-2, Envisat and CryoSat satellite missions between 1992 and 2017. The study also used simulations of snowfall over the same period produced by the RACMO regional climate model. The team found that fluctuations in snowfall tend to drive small changes in height over large areas for a few years at a time, whereas the most pronounced changes in ice thickness coincide with signals of glacier imbalance that have persisted for decades.