Meridional Asymmetry in the Evolution of the Southern Ocean Carbon Sink Over the 21st Century in a High-resolution Model, 2025

The Southern Ocean plays a key role in removing anthropogenic carbon dioxide (CO₂) from the atmosphere. We use a novel high-resolution (1/10˚) model to predict carbon uptake in the Southern Ocean under high-emission CO₂ forcing (RCP8.5). The results show that the Southern Ocean contribution to the global ocean CO₂ sink increases from 40 to 50% by 2100. Moreover, the ocean CO₂ sink moves poleward. Our analysis indicates this is due to the high turnover rate of the Circumpolar Deep Water, which becomes increasingly undersaturated relative to atmospheric CO₂ and thus a greater CO₂ sink. The resolution in this model allows for the representation of mesoscale eddies, but increased eddy activity appears to have a minimal effect on enhanced carbon uptake.

Reference: Mortenson, E., Lenton, A., Shadwick, E., et al. (2025). Meridional asymmetry in the evolution of the Southern Ocean carbon sink over the 21^st century in a high-resolution model, 2025. Front. Mar. Sci., 12, 1589735. https://doi.org/10.3389/fmars.2025.1589735