Worldwide glacier retreat and associated future runoff changes raise major concerns over the sustainability of global water resources, but global-scale assessments of glacier decline and the resulting hydrological consequences are scarce. Here we compute global glacier runoff changes for 56 large-scale glacierized drainage basins to 2100 and analyse the glacial impact on streamflow.

Changes in the hydrology of high-altitude catchments may have major consequences for downstream water supply. Based on model projections with a higher spatiotemporal resolution and degree of process complexity than any previous intercontinental comparative study, we show that the impacts of climate change cannot be generalized. These impacts range from a high climatic sensitivity, decreasing runoff, and significant seasonal changes in the Central Andes of Chile to increasing future runoff, limited seasonal shifts, but increases in peak flows in the Nepalese Himalaya.