Towards understanding the effects of extreme events on Antarctic ice-sheet dynamics

Projections of Antarctica's future sea-level contribution are still subject to great uncertainties, especially with respect to changes in surface mass balance and sub-shelf melting. While the climatic forcing used as boundary condition for ice sheet models cover the average trend in mass balance with global warming, extreme events, such as heatwaves, are typically not yet considered. However, a number of record-breaking extreme events have been observed in recent years in Antarctica already and may become more frequent or extreme with ongoing climate change. Here we investigate the effects of heatwaves on ice-sheet dynamics: using a storyline approach for conducting a suite of numerical ice-sheet simulations, we explore the additional Antarctic contribution to future sea-level rise when atmospheric extreme events are considered in projections. We set this into perspective with anomalous freshwater fluxes from ocean-driven melting (and calving) and investigate the potential for abrupt shifts and tipping dynamics, which extreme events may cause or pre-condition.