“Glaciers are the best climate barometers”, says glaciologist Dr. Heïdi Sevestre, pointing out that glaciers act as natural reservoirs of snow and ice which supply drinking water, power energy generation and support agriculture for more than two billion people worldwide (ElicitPlant, n.d.). Because glaciers are sensitive to temperature shifts, their retreat and thinning offer some of the most direct insights into climate change. They also play a crucial role in regulating Earth’s climate by reflecting sunlight and cooling the planet. But these frozen reserves are shrinking fast. The Intergovernmental Panel on Climate Change (IPCC) reports that glaciers are retreating and snow seasons are getting shorter, reshaping landscapes and threatening water security across continents (IPCC, 2021).
The World Glacier Monitoring Service (WGMS) emphasizes that while field observations remain indispensable, an increasing share of glacier information now comes from spaceborne sensors, which extend coverage to remote and hazardous terrain and provide consistent, repeated observations over long time periods (WGMS, 2025).
Space technologies to support snow and glacier monitoring
Because many glaciers lie in remote mountain ranges or polar regions, monitoring them from the ground is extremely difficult. Satellites make it possible to observe these frozen landscapes consistently and globally. The Global Land Ice Measurements from Space (GLIMS) database, for example, has assembled outlines for more than 200 000 glaciers, creating an essential resource for climate research and water planning (NASA Earthdata, 2025). Copernicus highlights that regular optical imaging enables detailed monitoring of glacier termini, melt dynamics and seasonal snow cover, even at the scale of individual glaciers (Copernicus, 2022), while repeat radar (e.g., Sentinel-1) supports mapping glacier flow/velocity and deformation, including under cloud cover and at night. Altimetry missions such as NASA’s Ice, Cloud, and land Elevation Satellite (ICESat-2) and ESA’s CryoSat-2 measure changes in glacier elevation, while the Gravity Recovery and Climate Experiment (GRACE) and the Follow On (GRACE-FO) missions detect regional changes in mass balance (National Snow and Ice Data Center and (NSIDC) 2025, ESA 2025, NASA JPL 2025). Synthetic aperture radar (SAR) and interferometry allow velocity mapping and deformation analysis under cloud cover and at night, supporting hazard assessment for avalanches and glacial lake outburst floods (Jarke, 2024).
