This study presents the Regional Integrated model of Climate and the Economy (RICE), a dynamic, general-equilibrium model that analyzes different national strategies in climate change policy. The model compares pure market solutions, efficient cooperative outcomes, and noncooperative equilibria. Key findings include: 1. **Emission Reductions**: Cooperative policies show significantly higher levels of emissions reductions compared to noncooperative strategies. 2. **Policy Divergence**: There are substantial differences in the levels of controls in both cooperative and noncooperative policies among different countries. 3. **High-Income Countries**: High-income countries may be the major losers from cooperation due to their relatively high emissions and declining economic shares. The RICE model divides the global economy into 10 regions, each with its own initial capital stock, population, and technology. The model integrates economic activity with greenhouse gas emissions and climate change, allowing for the calculation of efficient and noncooperative paths. The cooperative solution is identified as the one that generates an efficient level and distribution of emissions, while the noncooperative solution reflects individual nations' self-interested actions. The study also examines the economic and environmental impacts of different strategies, finding that the cooperative solution leads to higher world output and emissions by the end of the next century compared to other models. The cooperative strategy reduces global temperature by 0.22°C in 2100, while noncooperative strategies reduce warming by only 0.086°C. The cooperative solution is more economically efficient, but it may not emerge as the outcome of international negotiations due to the high costs and distributional issues. Overall, the study highlights the importance of cooperation in addressing climate change and the potential economic and environmental impacts of different policy choices.This study presents the Regional Integrated model of Climate and the Economy (RICE), a dynamic, general-equilibrium model that analyzes different national strategies in climate change policy. The model compares pure market solutions, efficient cooperative outcomes, and noncooperative equilibria. Key findings include: 1. **Emission Reductions**: Cooperative policies show significantly higher levels of emissions reductions compared to noncooperative strategies. 2. **Policy Divergence**: There are substantial differences in the levels of controls in both cooperative and noncooperative policies among different countries. 3. **High-Income Countries**: High-income countries may be the major losers from cooperation due to their relatively high emissions and declining economic shares. The RICE model divides the global economy into 10 regions, each with its own initial capital stock, population, and technology. The model integrates economic activity with greenhouse gas emissions and climate change, allowing for the calculation of efficient and noncooperative paths. The cooperative solution is identified as the one that generates an efficient level and distribution of emissions, while the noncooperative solution reflects individual nations' self-interested actions. The study also examines the economic and environmental impacts of different strategies, finding that the cooperative solution leads to higher world output and emissions by the end of the next century compared to other models. The cooperative strategy reduces global temperature by 0.22°C in 2100, while noncooperative strategies reduce warming by only 0.086°C. The cooperative solution is more economically efficient, but it may not emerge as the outcome of international negotiations due to the high costs and distributional issues. Overall, the study highlights the importance of cooperation in addressing climate change and the potential economic and environmental impacts of different policy choices.