Observational Contrains on the Global Atmospheric Co ₂ Budget

TLDR

The study combines observed atmospheric CO₂ concentrations with surface ocean partial pressures to identify globally significant CO₂ sources and sinks. Atmospheric data are compared with boundary‑layer concentrations derived from a general circulation model’s transport fields for specified source‑sink distributions. The north‑south concentration gradient can only be maintained if Northern Hemisphere sinks exceed Southern ones, and the small oceanic partial‑pressure differences indicate that terrestrial ecosystems absorb most of the excess CO₂.

Abstract

Observed atmospheric concentrations of CO(2) and data on the partial pressures of CO(2) in surface ocean waters are combined to identify globally significant sources and sinks of CO(2). The atmospheric data are compared with boundary layer concentrations calculated with the transport fields generated by a general circulation model (GCM) for specified source-sink distributions. In the model the observed north-south atmospheric concentration gradient can be maintained only if sinks for CO(2) are greater in the Northern than in the Southern Hemisphere. The observed differences between the partial pressure of CO(2) in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO(2). Therefore, a large amount of the CO(2) is apparently absorbed on the continents by terrestrial ecosystems.