Future levels of carbon dioxide emissions from fossil fuels are an important determinant of the severity and timing of global warming due to elevated levels of radiatively active (greenhouse) gases in the atmosphere. Many studies have addressed this issue,. These include Rotty (1977), Keeling and Bacastow (1977), Siegenthaler and Oeschger (1978), JASON (1979), Marchetti (1980), IIASA in Haefele (1981), Lovins (1981), Hamm (1982), Nordhaus and Yohe (1983), and Reister and Rotty (1983). Ausubel and Nordhaus (1983) provide a recent critical review of emissions forecasts with a focus on methodological development, citing the advance in methodological sophistication leading to improvements in understanding long-term patterns of energy use and their relationship to CO2 emissions.