Atmosphere-ocean general circulation model with the carbon cycle

Results from numerical experiments with an atmosphere-ocean general circulation model coupled to the carbon evolution cycle are analyzed. The model is used to carry out an experiment on the simulation of the climate and carbon cycle change in 1861-2100 under a specified scenario of the carbon dioxide emission from fossil fuel and land use. The spatial distribution of vegetation, soil, and oceanic carbon in the 20th century is generally close to available estimates from observational data. The model adequately reproduces the observed growth of atmospheric CO2 in the 20th century and the uptake of excess carbon by land ecosystems and by the ocean in the 1980s and 1900s. By 2100, the atmospheric CO2 concentration is calculated to reach 742 ppmv under emission and land-use scenario A 1 B. The feedback between climate change and the carbon cycle in the model is positive, with a coefficient close to the mean of all the current models. The ocean and land uptakes of the CO2 emission by 2100 in the model are 25 and 19%, which are also close to the mean over all models.