Glacier surging and surge-related hazards in a changing climate

Glacier surges are ice flow instabilities characterised by periods of acceleration, during which mass is rapidly transferred from higher to lower elevations and the glacier front often advances. Surges are typically recurrent and can substantially influence regional patterns of glacier mass loss and cause hazards impacting people and infrastructure. In this Review, we provide a global synthesis of glacier surging and the influence of climate and impacts of climate change on the distribution and behaviour of surge-type glaciers and surge-related hazards. Globally, more than 3,100 glaciers have been classified as surge-type, within which a broad range of surging behaviour has been documented. The fundamental control on surging is the evolution of basal friction leading to sustained enhanced basal sliding. Most surge-type glaciers are clustered in the Arctic/Subarctic (48.3% of all surge-type glaciers) and High Mountain Asia (50.5%), where climate conditions are conducive to the development of surge instabilities, and where there is emerging evidence that climate warming is changing surge behaviour. At least 81 surge-type glaciers globally have caused hazards, primarily in High Mountain Asia. Future research should prioritise acquiring additional spatiotemporally high-resolution remote sensing data and direct observations of basal processes during all stages of surges, improving numerical models to better capture the underlying mechanisms and diversity of surges, and projecting the behaviour and distribution of surge-type glaciers under future climate warming.