Antarctic ice shelves at risk of collapse by mid-century

Abstract Projections show that Antarctic surface melt will increase through the current century, potentially accelerating ice shelf collapse and global sea level rise 1–3. However, a high-resolution map of projected melt is currently lacking, which limits the accuracy of predictions of hydrofracturing 2 and loss of buttressing to grounded ice 4. Here, we present 100-meter projections of Antarctic surface melt potential under Shared Socio-economic Pathways (SSPs) 1-2.6, 2-4.5, 3-7.0, and 5-8.5. These projections are generated from a spatially-distributed statistical model 5 trained on 30 years of observational data, and uses high-resolution topographic data 6 to downscale forcing temperature fields. Local temperature corrections arising from this downscaling (but typically absent from general circulation models) are up to 6°C, comparable to global temperature change under the highest greenhouse gas emissions scenarios by 2100 7. Using these more accurate temperature fields our high-resolution downscaled melt calculations show that Larsen-C, Shackleton, Thwaites, Getz, and Totten ice shelves will all be at high risk of collapse from mid-century due to increased surface melt, even if emissions follow the mid-range SSP3-7.0 pathway. Future trajectories of latitudinal melt migration show that SSP1-2.6 is the only emissions pathway under which future Antarctic surface melt is stabilized at present levels.