EAPS

Title: Ups and downs of last interglacial sea level

Abstract: The last interglacial (MIS 5e, 125 ka) marks a time during which global mean temperatures were 1-2º warmer than pre-industrial values. This time period has therefore been used as a natural laboratory for studying ice sheet stability and sea level rise in a warmer world and insights gained from this period can be used to improve predictions of future sea level change. Local sea level during the last interglacial can be reconstructed using sea level indicators such as fossil corals. In order to infer global mean sea level, or equivalent ice volume, one needs to correct local sea level estimates for post-depositional deformation. In this talk I will discuss two geodynamic processes that cause post-depositional deformation, namely glacial isostatic adjustment and dynamic topography. I will show that dynamic topography contributes to sea level change over this time period and that model predictions are significantly correlated with observed sea level highstands. I will further discuss how glacial isostatic adjustment affects last interglacial sea level and that this signal is very sensitive to the penultimate deglaciation (MIS 6). I will show that combining these insights with field data from the Bahamas put new constraints on the size of MIS 6 ice sheets and can be used to derive a new estimate of global mean sea level during the last interglacial. I will present this estimate, put it in context of earlier work, and provide an outlook of how these findings can affect predictions of future sea level change.