Dynamics of air–sea carbon dioxide fluxes and their trends in the global context

This article reviews the dynamics of CO₂ fluxes in the global scenario. Most of the available techniques for sea-surface CO₂ partial-pressure estimation are regional models that depend on the key regulating parameters of partial pressures. Global-scenario of fluxes reveals a contrasting trend, indicating subpolar- and polar-waters dominated by physical forcings in winter, releasing CO₂ whereas a biological drawdown of atmospheric CO₂ in summer. In the tropical oceans, thermal-regulation weakens biological forcing leading to influx in winter and outflux in summer. The Atlantic Ocean acts as an intense sink (–815 to –1295 mmol Cm^–2 yr^–1); the strong source in the Pacific-equatorial belt is balan­ced by temperate sinks. The Indian Ocean as a whole acts as a sink (–8.41  × 1015 mmol C yr^–1) whereas the northwestern sub-basin acts as a source (2.04  × 1015 mmol C yr^–1). The net global ocean uptake is 50  × 1015 mmol C yr^–1 where the physical- and biological-forcings along with seasonality play crucial roles in the flux direction