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

Polar temperatures during the Last Interglacial [LIG; similar to 129 to 116 thousand years (ka)] were warmer than today, making this time period an important testing ground to better understand how ice sheets respond to warming. However, 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 Britain, France, and Denmark. Because of 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 change. We find that the Antarctic contribution to LIG global mean sea level peaked early in the interglacial (before 126 ka), with a maximum contribution of 5.7 m (50th percentile, 3.6 to 8.7 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.

Automated summary

By analyzing observational data from Britain, France, and Denmark, it has been found that during the Last Interglacial, the Antarctic had a significant contribution to global sea-level rise, peaking in the early phase of the interglacial. These findings are important for understanding the response of ice sheets to climate warming.