Enhanced CO2 outgassing in the Southern Ocean from a positive phase of the Southern Annular Mode

We investigate the interannual variability in the flux of CO2 between the atmosphere and the Southern Ocean on the basis of hindcast simulations with a coupled physical‐biogeochemical‐ecological model with particular emphasis on the role of the Southern Annular Mode (SAM). The simulations are run under either pre‐industrial or historical CO2 concentrations, permitting us to separately investigate natural, anthropogenic, and contemporary CO2 flux variability. We find large interannual variability (±0.19 PgC yr−1) in the contemporary air‐sea CO2 flux from the Southern Ocean (