Timothée Bourgeois is a researcher at NORCE and is affiliated to the Bjerknes Center. He defended his PhD in 2017 at the LSCE/IPSL in Paris, France on the impacts of anthropogenic perturbations on the biogeochemistry of the global coastal ocean. After 2 postdocs (Dalhousie University, Canada and here at NORCE), he has been recently hired as a NORCE researcher. His research expertise is focused on the ocean carbon cycle using a range of models from regional and global ocean-only configurations (NEMO-PISCES) to Earth system models.
The Southern Ocean between 30°S and 55°S is a major sink of excess heat and anthropogenic carbon thanks to the formation and subduction of Antarctic intermediate and mode waters. Model projections of these sinks remain highly uncertain. Reducing such uncertainties is required to effectively guide the development of climate mitigation policies for meeting stringent climate targets. Here, we show that the large spread in the projections of future excess heat uptake efficiency and cumulative anthropogenic carbon uptake in this region are strongly linked to the models’ contemporary stratification. This relationship is robust across two generations of Earth system models and is used to reduce the uncertainty of future estimates of the cumulative anthropogenic carbon uptake by up to 53% and the excess heat uptake efficiency by 28%. Our results highlight that, for this region, an improved representation of stratification in Earth system models is key to constrain future carbon budgets and climate change projections.
Arranged date for the seminar talk: April 25, 2022 at 14:15