Glaciers are shrinking at an alarming pace, and satellites have long been crucial for tracking these changes at a global scale. Yet, despite decades of progress, this essential capability is now at risk as emphasized by a recent Eos article. Several key long-running missions that provide open and high-resolution data are nearing the end of their lifespans. Without follow-up plans, decades of carefully built glacier records could be disrupted.

For more than two decades, satellites have been the backbone of glacier monitoring, enabling precise assessments in remote regions where fieldwork is nearly impossible. But this backbone is weakening. The imminent retirement of key sensors, uncertainties around future laser and radar missions, and unclear plans for follow-on gravity satellites all threaten to open serious gaps—right when consistent records are most needed.

A clear call for action

Together with our international colleagues, we have outlined five urgent priorities to ensure continuity in glacier monitoring:

• Unlock and utilize historical aerial and declassified satellite archives for longer-term baselines.
• Ensure continuity and open access to new satellite missions, supported by interim airborne campaigns to bridge potential gaps.
• Advance next-generation technologies such as full-swath lidar systems and gravity constellations.
• Promote open scientific access to commercial and defense imagery to fill spatial and temporal observational gaps.
• Expand and modernize in-situ observation networks, particularly in under-monitored regions such as Central Asia, the Andes, and the polar periphery.

Recent findings from space Since 2000, Earth has lost approximately 5 % of its global glacier mass—a significant and measurable decline revealed through satellite-based observations. This has recently been emphasized by a publication of the community-led initiative – the Glacier Mass Balance Intercomparison Exercise – which integrates multiple observation types, including in-situ measurements and a variety of satellite techniques (digital elevation model differencing, altimetry, gravimetry). By combining these approaches, more accurate estimates of global glacier mass change are possible.

Related publications

Zemp, M., L. Jakob, F. Brun, T. Sutterley, and B. Menounos (2025), Glacier monitoring from space is crucial, and at risk, Eos, 106, https://doi.org/10.1029/2025EO250290.

The GlaMBIE Team. Community estimate of global glacier mass changes from 2000 to 2023. Nature 639, 382–388 (2025). https://doi.org/10.1038/s41586-024-08545-z

Jacqueline Bannwart, Michael Zemp, World Glacier Monitoring Service (WGMS)