The recent international negotiations highlighted the inability of national governments to agree to binding targets to curb greenhouse gas emissions. At the 2009 Copenhagen summit, nearly 120 heads of state announced a symbolically drafted political declaration, dubbed the “Copenhagen Accord.” However, the document lacks formal adoption and does not include detailed action plans for both industrialized and developing countries. 1 Despite policy failure at the national level, some cities around the world have come together to mitigate global warming. These cities are setting the greenhouse gas (GHG) reduction target, designing action plans, implementing policies, and collaborating with other cities to achieve common goals of climate policies. Given that cities account for 70 percent of GHG emissions, 2 this is an important development that state-centric accounts of global environmental politics tend to overlook. Indeed, cities have become more signifi cant actors in transnational climate change governance in that (1) cities have been establishing their own GHG emission reduction targets and implementing climate policies within their jurisdictions and (2) these local governments have been forming transnational networks for collective action to confront global climate change.