'Fast-track' sensitivity of freshwater fluxes to climate scenarios (D4.1)

MAKE SURE YOU ARE ACCESSING VERSION 2 OF THE 15 October 2024. As global temperatures rise, Antarctica's grounded ice sheet and floating ice shelves are losing mass at an accelerating rate, releasing meltwater into the Southern Ocean. This increasing freshwater discharge poses significant implications for global climate dynamics. We now have clear evidence that freshwater discharges from Antarctica (ice-shelf melting, iceberg calving, subglacial discharge and surface runoff) are impacting the oceanography of the surrounding oceans, underscoring the urgentneed to integrate these effects into climate models. In previous CMIP rounds, models either assumed that the ice sheets were in mass balance or that discharge from the ice sheets was constant in time.Consequently, climate projections lack a detailed representation of spatiotemporal trends in ice-sheet freshwater fluxes and their impact on the global climate system, introducing unquantified uncertainties in future climate and sea-level projections. In this deliverable, we present a dataset that offers projections of freshwater fluxes from the Antarctic ice sheet and uncertainty estimates spanning from the present day to the year 2300 that can be implemented as a forcing for climate models thatdo not include interactive ice sheets. These projections are derived from an ensemble of historically calibrated standalone ice sheet model projections generated with the Kori-ULB ice flow model (https://github.com/FrankPat/Kori-ULB), under different climate scenarios up to 2300. We assess the sensitivity and spread in freshwater fluxes projections in response to climate forcing and a comprehensive range of uncertain glaciological processes.