Which physical and biogeochemical processes influence ocean carbon sequestration during the last glacial cycle in climate models?
| Quand ? |
Le 22/01/2024, de 11:00 à 12:00 |
|---|---|
| Où ? | Salle des Thèses |
| Participants |
Fanny Lhardy |
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The BBVA Foundation Frontiers of Knowledge Award in the Climate Change category has just been awarded to five European scientists who used ice cores to establish a "fundamental coupling" between greenhouse gas concentrations and the increase in global average temperatures over the past 800,000 years. Their research has shown that glacial-interglacial cycles are associated with variations in atmospheric CO2 of about 80 to 100 ppm. Due to its large carbon storage capacity, the ocean seems to have played a key role in these variations. However, the processes explaining a greater carbon sequestration in the ocean at the Last Glacial Maximum (wrt. the pre-industrial) remain debated, as they are poorly constrained by palaeoclimatic data and climate models.
In this talk, I evaluate simulations run with coupled climate-carbon models using data measured in ice or marine cores. By characterising model biases using sensitivity tests and/or multi-model comparisons, I show that a good model representation of sea level variations, convection processes in the Southern Ocean but also biogeochemical fluxes (such as sinks and sources of whole-ocean alkalinity) is critical to better understand and simulate atmospheric CO2 variations during the last glacial cycle.