Anthropogenic Intensification of Surface Ocean Interannual pCO ₂ Variability

Abstract We use several global coupled atmosphere‐ocean‐biogeochemistry models from the Coupled Model Intercomparison Project (CMIP5) to show that the global interannual variability of the sea surface pCO 2 (calculated as 1 σ ) will increase by ∼64 ± 20% by 2040–2090 relative to the beginning of the industrial revolution under the RCP8.5 scenario. All models agree that the increase in variability is a consequence of a larger background pCO 2 and a lower buffering capacity that enhance the response of pCO 2 to the fluctuations of surface temperature (T) and dissolved inorganic carbon (DIC). The most skillful group of models under present‐day conditions shows a future global decrease in DIC fluctuations that will weaken the pCO 2 interannual variability (IAV). The remaining uncertainties in the projected evolution of pCO 2 variability regionally highlight the need for continuous carbon monitoring programs which will contribute to a better understanding of the oceanic carbon sink's response to increased green house emissions.