Stratospheric ozone depletion reduces ocean carbon uptake and enhances ocean acidification

Observational and atmospheric inversion studies find that the strength of the Southern Ocean carbon dioxide (CO₂) sink is not increasing, despite rising atmospheric CO₂. However, this is yet to be captured by contemporary coupled-climate-carbon-models used to predict future climate. We show that by accounting for stratospheric ozone depletion in a coupled-climate-carbon-model, the ventilation of carbon rich deep water is enhanced through stronger winds, increasing surface water CO₂ at a rate in good agreement with observed trends. We find that Southern Ocean uptake is reduced by 2.47 PgC (1987- 2004) and is consistent with atmospheric inversion studies. The enhanced ventilation also accelerates ocean acidification, despite lesser Southern Ocean CO₂ uptake. Our results link two important anthropogenic changes: stratospheric ozone depletion and greenhouse gas increases; and suggest that studies of future climate that neglect stratospheric ozone depletion likely overestimate regional and global oceanic CO₂ uptake and underestimate the impact of ocean acidification.