Ice sheets are vast continental-scale masses of glacial ice that cover more than 50,000 km². Today, only two ice sheets exist: the Antarctic Ice Sheet and the Greenland Ice Sheet. Ice sheet variations are sensitive indicators of climate change as their mass balance (gains versus losses) directly indicates global warming. Monitoring ice sheets is essential for understanding how they respond to climate change and projecting how their variations influence the global water cycle, surface energy budget, sea level change, and ocean circulation patterns. Geodesy provides time series of ice volume changes inferred from satellite altimetry measurements, and mass changes inferred from satellite gravimetry. These observations are essential for studying the mass budget (input-output balance), projecting sea level change, improving climate and weather models, predicting changes in ocean salinity and circulation, and informing global climate agreements and adaptation strategies. The following geodetic products are key to realising, monitoring and applying this Essential Geodetic Variable: