Global sea level change since the Mid Holocene: Background trends and climate-ice sheet feedbacks

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Over the last few decades the contribution of the ice sheets of Greenland and Antarctica to sea-level rise has grown. It is however not clear to what extent the recent reduction in land ice mass is related to the globally warming climate. We aim to assess natural variability and long-term trends in the ice sheet´s mass balance in relation to changes during the industrial period. For this purpose we turn our attention to the last 6000 years, from Mid Holocene to present, as this period is characterized by similar to present ice sheet geometries as well as moderate and gradual climate change before the onset of rising greenhouse gas concentration. The base of this project focuses on ice sheet variations of Greenland and Antarctica over the last 6000 years, combining ice sheet simulation and climate simulations operating on different spatial and temporal scales. Additionally we will focus on interactions between the climate system and the ice sheets, which are usually unresolved in millennial scale simulations. In particular, we will analyze - the response of the two ice sheets to climate variations over the last 6000 years - the small scale ocean-ice shelf interaction on the basal melt rates in ice shelf cavities around Antarctica - the ice sheet-climate feedbacks associated with Greenland melt water runoff - the impact of different basal melt scenarios on the mass balance of Antarctica - the skill of potential parameterizations of basal melting, which are feasible for Earth system modeling on long time scales.