This study examines greenhouse gas (GHG) emission reduction pathways in response to South Korea’s Constitutional Court ruling requiring legislation of annual reduction targets for 2031 ~ 2049. Through analysis of domestic and international cases, we investigate approaches to establishing reduction pathways, focusing on major economies including the EU, Germany, the UK, the US, Australia, China, and Japan. Our review of domestic literature reveals that, while several simulation-based studies exist, they primarily focus on reduction costs without considering benefits, highlighting the need for a more comprehensive approach. The international review shows that, while Germany has legislated specific annual targets and the UK employs five-year carbon budgets, most countries have not yet established detailed reduction pathways between their 2030 NDC and 2050 carbon neutrality goals, highlighting the importance of the Korean endeavor to design annual reduction targets. We find that Germany and the EU have adopted flexible approaches to emission pathways, while the UK emphasizes cost-benefit considerations in pathway design. Based on these findings, we explore the possibility of using cost-benefit analysis with integrated assessment models to evaluate various pathway options, demonstrating how this approach can balance economic efficiency with political feasibility. We suggest several important implications. First, comprehensive research on reduction pathways needs to be expanded in Korea. Second, flexible institutional arrangements, similar to those adopted in Germany and the UK, could be more effective than rigid annual targets. Third, we emphasize Korea-specific pathways that reflect national characteristics such as industrial structure and climate vulnerabilities. Finally, broad social discourse involving various stakeholders is essential, as the chosen pathway will have significant societal impacts over the coming decades.