Date of Original Version
AlI 74 ppm (1 ppm = 1.77 E 14 moles CO2) of anthropogenic CO2 can be accounted for in atmosphere (45 ppm) and ocean (29 ppm) by a simple "diffusive / descending-water" model. 3.8 ppm remain in the mixed layer (at equilibrium), 19.1 have diffused into intermediate waters (at 1.3 cm2 / sec). and 5.7 ppm have been advected by the North Atlantic Deep, and the Antarctic Intermediate and Bottom Waters. The diffusive uptake must be driven by a realistic "interrupted exponential" atmospheric driving function, with 23 years of no growth between the World Wars. The 575 m surface-ocean box required by a two-box air-sea equilibrium model, is a useful parameterization of diffusion plus thermohaline circulation, with only the 75 m wind-stirred layer near equilibrium. Future atmospheric projections from such a model are at the upper limit of those from kinetic box models, reaching 600 ppm by 2030 AD for most scenarios.
Macintyre F (1980). The absorption of fossil-fuel CO2 by the ocean. Oceanologica Acta, 3(4), 505-516. Open Access version : https://archimer.ifremer.fr/doc/00323/43431/
Available at: https://archimer.ifremer.fr/doc/00323/43431/