Contributions of supraglacial lakes to the Greenland Ice Sheet melting

Abstract. The Greenland Ice Sheet is considered a potential tipping element in the Earth system, as it may undergo rapid and irreversible ice loss. The complete loss of the ice sheet would lead to significant sea-level rise, posing an existential risk to humanity. Supraglacial lakes on the ice sheet enhance melting by reducing surface albedo and increasing melt rates during summer. We develop a simple conceptual model to investigate this process. The model consists of three coupled partial differential equations describing the temporal evolution of ice, water, and snow thickness within a simplified physical domain of Greenland, all driven by the annual temperature cycle. Model integrations show that, under realistic conditions, the presence of supraglacial lakes accelerates local ice melting and modifies the long-term ice-sheet topography. Regions with recurrent lake formation exhibit greater elevation differences. Under Shared Socioeconomic Pathway warming scenarios, only the lowest-emission scenarios prevent the onset of a self-sustaining melt–elevation feedback that could ultimately lead to complete ice-sheet loss. These results highlight the critical role of supraglacial lakes in amplifying ice-sheet melt and suggest that their influence should be more explicitly represented in comprehensive climate and ice-sheet models.