The Ups and Downs of Last Interglacial Sea Level

November 5, 2020
4:00 pm - 5:00 pm

Jacky Austermann, Lamont-Doherty Earth Observatory

The Last Interglacial (125 kyr ago) was the last time in Earth’s history when temperatures were on average higher than they are today. Constraining and understanding the evolution of sea level during this time can therefore inform the stability of ice sheets in our currently warming world. Austermann will present work from an ongoing project that aims to reconstruct the evolution of last interglacial sea level in the Bahamas based on fossilized reefs and sedimentary features. Relating local sea level to the ice equivalent global mean requires a correction for any uplift or subsidence of the Bahamian archipelago. Austermann will describe two processes that lead to significant solid Earth deformation over the Pleistocene – glacial isostatic adjustment and dynamic topography – and will show that the Bahamas are uniquely located to constrain uncertain parameters in both of these processes. Combining field evidence with insights on solid Earth dynamics yields a new estimate of Last interglacial sea level and the sensitivity of Earth’s ice sheets to gradual warming.

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