Greenland and Antarctica as Interacting Constitutes in AWI-ESM

It is highly challenging to include both the Antarctic and Greenland ice sheets in a state-of-the-art earth system model. Our presentation demonstrates our system's design, the essential steps before coupling the entire system, the challenges faced in the coupling process, and the initial findings from our series of simulations for warming scenarios spanning the next few centuries until 2500.

We will highlight the existing limitations in the computed climate conditions that affect the behavior of ice sheets. These motivate our system's design. For instance, ocean temperature biases in the marginal seas around Antarctica inhibit its direct use to determine basal melting of floating ice shelves fringing Antarctica despite extensive tuning efforts. As a result, we have developed a flexible framework deemed necessary to adequately represent the currently observed ice sheet state. The still delicate integration of ice sheets into climate models directs the spin-up procedure of ice sheet models. The procedure's results and its consequences are presented and discussed. In particular, the available iceberg calving mechanism has been demanding in our simulations because we allow for freely waxing or waning ice shelf edges around Antarctica, unprecedented in coupled climate-ice sheet model systems.

Finally, the first results of our fully coupled simulations complete the presentation. These focus on the interaction between the climate system and Antarctica or Greenland and its influence on primary climatic conditions. In our model system, interacting ice sheets shape the climate state, creating feedback loops that affect the ice sheet state itself. This interaction may ultimately counteract the disintegration of ice sheets. Supposed it is a robust result, it implies that standalone ice sheet simulations may overestimate future sea level contributions.