Abstract
We use global coupled atmosphere-ocean-biogeochemistry models from the
Coupled Model Intercomparison Project (CMIP5), under the RCP8.5
scenario, to show that the global interannual variability of the sea
surface pCO (calculated as 1σ) could increase by 62 ± 22 % by 2090.
This amplification is a consequence of a larger background pCO and a
lower buffering capacity that enhance the response of pCO to surface
temperature (T) and dissolved inorganic carbon (DIC) changes.
The amplification is counteracted by a decrease in the sea-surface DIC
interannual variability, which will likely cause a strong reduction on
the pCO’s variability in the equatorial Pacific. The potential changes
in seawater carbonate chemistry are simulated with higher consistency
than those in the DIC and T anomalies driven by ocean circulation and
biology. The changes in sea-surface pCO interannual variability are
reflected in the ocean-atmosphere flux of CO and need to be accounted
for future carbon projections.