An atmosphere model composed of a narrow band radiative-convective (RC) code coupled with a one-dimensional chemistry and transport code is described. The RC model, formulated in log-pressure coordinates, includes accurate solar absorption calculations for O3, O2, H2O, and CO2. Infrared heating and cooling by CO2, O3, and H2O are calculated with a narrow band formulation, while broader band formulations are used for CH4, N2O, CFC 11, and CFC 12. The atmospheric chemistry and transport model uses photochemical reaction rate data from Jet Propulsion Laboratory publication 82-57. The calculated steady state atmospheric response to several potential perturbations is discussed. Doubling the atmospheric CO2 level yields a change in total ozone of +2.9% and a surface temperature increase of 1.7 K. The continued release of chlorofluorocarbons (CFC's) alone at nominal rates gives a calculated column ozone change of -5.7% at steady state, while for a combined 2¿CO2+CFC perturbation the result is -3.5%. Ozone perturbations due to increases in N2O,CH4, and aircraft are also discussed. Two coupled scenarios including projected changes that may occur in about 100 years due to all these identified man-made perturbations are discussed. The calculated ozone column changes are -4.5% and +1.5%, assuming fixed and doubled methane source strengths, respectively.