Glacier surging and surge-related hazards in a changing climate

Glacier surges are ice flow instabilities characterized by periods of acceleration, during which mass is rapidly transferred from high to low elevations and the glacier front often advances. In this Review, we outline global trends in glacier surging and the influence of climate on the distribution and behaviour of surge-type glaciers and surge-related hazards. Glaciers exhibit diverse surging behaviours and typically recur at intervals that range from 5 years to over 100 years, with all surges largely driven by a reduction in basal friction. Most of the ~3,100 surge-type glaciers identified globally are clustered in the Arctic and Subarctic (48.3%) and High Mountain Asia (50.5%), where climate conditions are conducive to the development of surge instabilities, and there is emerging evidence that climate warming is changing surge behaviour. At least 81 surge-type glaciers globally have caused hazards such as ice-dammed glacial lake outburst floods, which can lead to infrastructure damage and loss of life. Future research should acquire spatiotemporally high-resolution remote-sensing data and direct observations of basal processes during all stages of surges, develop numerical models to better capture surge mechanisms and diversity, and project the impact of future climate warming on surge-type glacier behaviour and distribution.