The ice-cavity feedback in an Earth system model

The melting of the Antarctic ice shelves becomes critical in a warming climate. However, the ocean component of climate models do not consider the effect of the Antarctic ice-shelf cavities. Here, we implement ice-shelf cavity features into the new AWI Earth system model (AWI-ESM2) based on unstructured meshes allowing for varying resolution in a multi-scale approach. We create a global mesh explicitly resolving the Antarctic ice-shelf cavities and evaluate the effect of the cavities under global warming scenarios. The new mesh provides a more realistic freshwater input into the Antarctic coast and the Southern Ocean. In an extreme warming climate scenario, the melting of the Antarctic ice shelves gets stronger by a factor of ~3, affecting the North Atlantic salinity and the overturning circulation. We conclude that the incorporation of ice-cavity feedback is essential to study the past, present, and future. Our approach might be seen as a prototype for the next phase of the Coupled Model Intercomparison Project.