FirnMelt: Greenland’s Melting Firn and Ice Sheet Response

Firn currently covers almost 90 % of the surface of the Greenland Ice Sheet. Most of Greenland’s firn plateau experienced only occasional melt in the past but ever rising temperatures increase melting and it is uncertain how a future melting firn plateau will impact ice sheet mass balance, hydrology and ice dynamics. Assessing these impacts requires coupling firn models to ice sheet hydrology and ice dynamics models.

The FirnMelt ERC Synergy project will assess the Greenland Ice Sheet’s reaction to increased melting across its vast firn plateau. The project starts in April 2026 and will last for six years. The project is led by four PIs and will involve about 20 scientific and technical staff. Here we detail planned methods, models and timeline of the five overarching project tasks, namely (i) large-scale in situ and remote sensing measurements of all types of firn and meltwater discharge, (ii) parameterizing melting firn based on these measurements, (iii) develop firn models able to simulate melting firn and firn meltwater discharge in three dimensions, (iv) embedding these models into a ice-sheet model suite where they are coupled to ice sheet hydrology and ice dynamics, and (v) calculating how Greenland’s melting firn plateau will impact the entire ice sheet and its sea level contribution, until the year 2300.