A review of the carbon dioxide greenhouse problem

Abstract

An enhanced “greenhouse effect” due to an increase in atmospheric CO 2 is expected to produce significant climatic changes. If the combustion of fossil fuels is the only anthropogenic source of atmospheric CO 2, measurements show that 54% resides in the atmosphere. The largest reservoir for the remaining 46% is the oceans. Known oceanic processes can account for 35% and the major uncertainty appears to be the role played by the intermediate waters. If, however, deforestation is as large a source of additional atmospheric CO 2 as some have suggested, carbon balance cannot be obtained with presently identified removal processes. Various computer models have been used to calculate the effects of increasing atmospheric CO 2. These include energy balance, radiative-convective and general circulation models (GCM's). Many feedback mechanisms must be considered including water vapour, clouds, oceans and the cryosphere. Although representing a considerable advance over other models, GCM's still require many approximations, of which the treatment of oceans and clouds are the most questionable. These models predict, for the scenario of the doubling of atmospheric CO 2, an increase in global surface temperature of about 3°C with larger increases, up to 10° at higher latitudes. Significant changes in evaporation and precipitation patterns are also indicated.