Direct and indirect contributions of ocean warming to the last interglacial sea-level highstand: insights and nuances for future predictions
Pinning down the sources contributing to the last interglacial (129 – 116 ka) sea-level highstand may be crucial to understanding the vulnerability of modern ice sheets to global warming. Today, ocean warming plays a direct role in sea level rise through thermal expansion and may play an indirect role in future sea level rise through basal melting and subsequent mass loss from the polar ice sheets.
Using the novel proxy of noble gas ratios measured in ice cores, we reconstruct mean ocean temperature (MOT) change during the penultimate deglaciation and last interglacial. We show that peak ocean temperatures were 1.1±0.3°C warmer than today, contributing 0.7±0.3m to thermosteric sea level. This MOT maximum occurred at the end of the termination, coincident with peak Antarctic temperature.
We suggest that most of this enhanced warming was related to a delay in the resumption of the Atlantic Meridional Overturning Circulation (AMOC) and a bipolar seesaw response in global temperature change across the penultimate deglaciation. We also hypothesize that the delayed AMOC recovery and early ocean warming triggered enhanced mass loss from Greenland and Antarctica in the early stages of the last interglacial.
Date: 12 November 2021, 13:30 (Friday, 5th week, Michaelmas 2021)
Venue: Online via zoom link
Speaker: Dr. Sarah Shackleton (Princeton University)
Organising department: Department of Earth Sciences
Part of: Earth Sciences departmental seminars
Booking required?: Not required
Booking url: https://www.earth.ox.ac.uk/events/direct-and-indirect-contributions-of-ocean-warming-to-the-last-interglacial-sea-level-highstand-insights-and-nuances-for-future-predictions/
Audience: Members of the University only
Editor: Maria Petrunova