Channelized melt beneath Antarctic ice shelves previously underestimated

While of critical importance for coastal communities, Antarctica’s future sea-level contribution remains highly uncertain. This uncertainty largely stems from the complex interaction between the ocean and the ice shelves, which is both difficult to observe and model. To better understand and constrain land-ice response to reduced buttressing exerted by ice shelves, efforts are needed to fully comprehend basal melt rates and their impact on ice shelf weakening and retreat. Here we present high-resolution basal melt maps (50 m) of vulnerable ice shelves based on a combination of stereo imagery and satellite altimetry, revealing pronounced channelized melting patterns whose melt rates were previously substantially underestimated (42–50%), which could result in faster channel breakthrough. Accurately simulating small-scale dynamics in ice-sheet models remains challenging but is essential for accurate sea-level rise projections. Channelized subsurface melting is an important process in the dynamics of ice shelves. Here the authors present observational data from Antarctic ice shelves and show that their basal melt is up to 50% higher than previously assumed.