Expansion of Antarctic surface melt through the 21st century

Climate models show that Antarctic surface melt will increase through the current century. Surface melting changes ice sheet albedo, the availability of liquid water for endemic and invasive species, and may even accelerate ice shelf collapse and global sea level rise. Here we show, using 1 km downscaled projections of potential Antarctic surface melt, that the total area experiencing surface melt will expand by more than 10% by 2100 under a Shared Socio-economic Pathway 3-7.0 scenario, with increased potential melt totals likely to threaten the viability of ice shelves mostly in the West Antarctic Peninsula and Amundsen Sea Embayment, through an elevated risk of hydrofracture. By calculating the latitudinal rate of melt migration we also find that Shared Socio-economic Pathway 1-2.6 is the only emissions scenario under which the rate of future Antarctic surface melt expansion will stabilize at present levels. Assessing the impact of rising air temperatures on the Antarctic Ice Sheet is hampered by the coarse resolution of climate models. Here, the authors use an observationally constrained statistical method to calculate surface melt at 1 km resolution.