The influence of wave-induced variability on ocean carbon uptake

Traditional gas transfer velocity formulations for air-sea CO₂ fluxes scale solely with wind speed, ignoring wave activity, including wave breaking and bubble-mediated transfers that enhance the rate of gas exchange. Here, we incorporate a wind-wave dependent gas transfer velocity formulation into an ocean general circulation model to quantify the effects of wave-induced spatiotemporal variability on CO₂ fluxes and ocean carbon storage. Our results reveal that wave activity introduces a hemispheric asymmetry in ocean carbon storage, with gains in the southern hemisphere, where wave activity is robust year-round, and losses in the northern hemisphere, where continental sheltering reduces carbon uptake. Compared to a traditional wind-dependent formulation, incorporating wave activity yields a modest global increase in ocean carbon storage of 4.3 PgC over 1959-2018 (~4%), but on average, enhances the CO₂ gas transfer velocity and flux variability by 5-30% on high-frequency and seasonal timescales in the extratropics and up to 200-300% during storms (>15 m s^-1 wind speed). The magnitude of fluxes from wave activity is comparable to expected marine carbon dioxide removal (mCDR) efforts. This underscores the need to incorporate wind-wave variability into modeled fluxes to distinguish natural variability from anthropogenic impacts and ensure accurate mCDR verification and monitoring.