Constraining the contribution of the Antarctic Ice Sheet to Last Interglacial sea-level

Polar temperatures during the Last Interglacial (LIG; ~129-116 ka) were warmer than today, making this time period an important testing ground to better understand how ice sheets respond to warming. Yet it remains debated how much and when the Antarctic and Greenland ice sheets changed during this period. Here we present a combination of new and existing absolutely dated LIG sea-level observations from southwest Britain, northern France, and Denmark. Due to glacial isostatic adjustment (GIA), the LIG Greenland ice melt contribution to sea-level change in this region is small, which allows us to constrain Antarctic ice melt. Combining data and GIA modelling, we find that the Antarctic contribution to LIG global mean sea level peaked early in the interglacial (prior to 125 ka), with a maximum contribution of 5.6 m (50th percentile, 3.3–8.8 m central 68% probability) before declining. Our results support an asynchronous melt history over the LIG, with an early Antarctic contribution followed by later Greenland ice-sheet mass loss