Assessing the Importance of Greenland's Ice Shelves for Future Sea Level Rise Predictions

The future evolution of Greenland’s remaining ice shelves is generally not considered a major contributor to the ice sheet’s overall mass loss. However, their role in buttressing the present-day ice sheet has not yet been quantified through a systematic analysis. Here we perform a series of experiments with the ice-sheet model Úa. Results from a control simulation with present-day ice shelf extents and atmospheric conditions are contrasted to RCP8.5 climate change scenario with 1) intact ice-shelves, and 2) the catastrophic and irreversible loss of all floating ice. Immediately following ice shelf collapse, ice flux across the grounding line doubles, leading to a sustained more than 4-fold increase in solid ice discharge, with implications for how freshwater flux influences local ocean circulation. By the end of the century, these end-member scenarios demonstrate a response of ~2.5 mm additional sea level rise due to ice shelf loss.