Global glacier-free topography reveals a large potential for future lakes in presently ice-covered terrain

Abstract

Abstract Glacier retreat transforms landscapes in polar and mountainous regions. Yet, the topography of the emerging terrain remains poorly known. Here, we present a physically consistent, global map of the ice-covered topography beneath all glaciers on Earth distinct from the ice sheets, derived from the three-dimensional higher-order Instructed Glacier Model, and constrained by extensive observational datasets. The map allows us to identify  > 50,000 possible future lakes in the presently ice-covered landscape, with a maximum total volume of 3,138 km 3 —enough to store 7 mm sea-level equivalent (SLE). Additionally, we estimate the total global glacier volume at 149.41 ± 29.28 × 10 3 km 3 (308 ± 60 mm SLE). Large overdeepenings near glacier fronts in High Mountain Asia suggest an increased risk for glacier lake outburst floods under glacier retreat. The subglacial topography and ice thickness data offer new opportunities for diverse cryospheric and Earth system studies, including refined projections of glacier changes and landscape evolution of deglaciated terrain.