Volcanoes stunt nearby glaciers

Glacierised volcanoes pose significant hazards to societies. Monitoring these volcanoes is therefore essential, though challenging, as traditional geophysical and geochemical methods for tracking volcanic activity can be hindered by glacier cover or remoteness. In this study, we analyse to what extent 307 active volcanoes worldwide impact the mass balance of glaciers within a 40 km radius, a total of 40667 glaciers, by comparing their relative median elevations. We show that glaciers near volcanoes are progressively confined to higher elevations closer to volcanoes, indicating that volcanic processes have a negative impact on nearby glacier mass balance. The influence of noneruptive and eruptive volcanic activity on glacier mass balance is primarily confined to glaciers within 5 km of volcanoes, a similar footprint to detected anomalies in thermal and deformation studies. Our results present a global assessment of volcanic effects on glacier mass balance, and could serve as a baseline for future monitoring efforts of how volcanic activity affects glaciers. © The Author(s) 2025.