Historical and Future Surface Mass Balance Contributions to Antarctic and Greenland Ice Sheet Freshwater Fluxes

Freshwater fluxes from the Antarctic and Greenland ice sheets play a critical role in sea-level rise, ocean circulation, and the global climate system. These fluxes arise from both dynamical processes—such as ice discharge, iceberg calving, and basal melting of ice shelves—and from surface mass balance processes. In Greenland, surface meltwater runoff is already a major contributor to freshwater input, and it is projected to become increasingly important in Antarctica as climate warming progresses. 

While regional climate models (RCMs) are key to studying climate at regional and local scales, relatively few are equipped with advanced snow and firn models capable of producing accurate surface mass balance results. Here, we present a comprehensive, state-of-the-art collection of regional climate model simulations (RACMO2, MAR, and HIRHAM5) for both Greenland and Antarctica, forced by historical and SSP-scenario CMIP6 Earth System Models and extending to the year 2100. We briefly assess the modelled surface mass balance, accumulation, melt, and runoff, and highlight aspects of atmosphere–snow/ice interactions that remain an active area of model development. This dataset can be used to prescribe freshwater fluxes from surface mass balance to oceanic or climate modelling experiments, or as a comparison against in situ observational datasets.