Greenland's ice-marginal lakes represent an important and dynamic component of meltwater storage

Abstract. Ice-marginal lakes are important components of glacierised landscapes, storing meltwater, influencing glacier dynamics, and regulating freshwater transfer to the ocean. Greenland (Kalaallit Nunaat) hosts a large concentration of ice-marginal lakes along the edge of the Greenland Ice Sheet, and its peripheral glaciers and ice caps. Here, we present a Greenland-wide remote sensing assessment of ice-marginal lakes between 2016 and 2025 to provide a comprehensive overview, and evaluate their role with ongoing glacier change. We identify 4038 lakes covering 4734.9 km², equivalent to 1 % of Greenland's ice-free land area. Lake number, area, and surface temperature show negligible change over the decade, indicating broadly stable conditions. However, in total these ice-marginal lakes store an estimated 462.5 Gt of meltwater, of which 67.0 Gt (14 %) has the potential to be rapidly released through glacial lake outburst floods (GLOFs). Our results demonstrate that ice-marginal lakes are a major and spatially heterogeneous component of Greenland’s meltwater system, functioning both as long-term water storages and as sources of episodic, high-magnitude outflow events. Their role remains under-represented in assessments of Greenland hydrology and freshwater fluxes, with implications for constraining Greenland’s contribution to global sea-level estimates.