A Comparison of the MIS-11 and MIS-5 Greenland Ice Sheet Contribution to Sea Level

Abstract:

Both Marine Isotope Stage 11 (MIS-11) and MIS-5 were interglacial periods during the Pleistocene that exhibited sea levels much higher than today and likely warmer temperatures too. Simulating the ice sheets during these times can provide insight into their sensitivity to climatic changes. Here we investigate the evolution of the Greenland ice sheet (GIS) during these two warm periods. We use the coupled climate-ice sheet model REMBO-SICOPOLIS to perform large ensembles of simulations over the last several glacial cycles. Paleo data from ice and ocean sediment cores is used to constrain the range of valid simulations.

We present probabilistic estimates of the contribution of the GIS to sea level for both MIS-11 and MIS-5. Furthermore our simulations provide information on the plausible range of changes regional climatic forcing that drive the changes in Greenland ice volume. In our simulations, the GIS loses significantly more volume during MIS-11 compared to MIS-5, even though insolation anomalies were stronger during the latter. Our results highlight the exceptional duration of MIS-11 as a key factor leading to higher volume losses. Importantly, the GIS does not reach equilibrium with the climatic forcing during either interglacial, which highlights the importance of the duration of enhanced climatic forcing on the survivability of the ice sheet in warm periods.