Modeling the Carbon System

Abstract

Claims that forest cutting (luring the last few decades has contributed significantly to the buildup in atmospheric CO2 have cast doubt on the validity of models used to estimate CO2 uptake by the ocean. In this paper we review the existing models and conclude that the box-diffusion model of Oeschger and his co-workers provides an excellent fit to the average distributions of natural and bomb-produced radiocarbon. We also take the first steps toward a more detailed ocean model which takes into account upwelling in the equatorial zone and deep water formation in the polar zone. The model is calibrated using the distribution of bomb-produced and cosmic ray-produced radiocarbon in the ocean. Preliminary calculations indicate that the fossil fuel CO2 uptake by this model will be greater than that by the box-diffusion model of Oeschger and others (1975) but not great enough to accommodate a significant decline in the mass of the terrestrial biosphere over the past two decades.