Alternative methods for quantifying the economic impacts associated with future increases in the ambient concentration of CO2 were examined. A literature search was undertaken, both to gain a better understanding of the ways in which CO2 buildup could affect crop growth and to identify the different methods available for assessing the impacts of CO2-induced environmental changes on crop yields. The second task involved identifying the scope of both the direct and indirect economic impacts that could occur as a result of CO2-induced changes in crop yields. The third task then consisted of a comprehensive literature search to identify what types of economic models could be used effectively to assess the kinds of direct and indirect economic impacts that could conceivably occur as a result of CO2 buildup. Specific attention was focused upon national and multi-regional agricultural sector models, multi-country agricultural trade models, and macroeconomic models of the US economy. The fourth and final task of this research involved synthesizing the information gathered in the previous tasks into a systematic framework for assessing the direct and indirect economic impacts of CO2-induced environmental changes related to agricultural production.