Subnational climate diplomacy is a concept that has been gaining attention in the field of International Relations in recent years. It refers to the way in which state and local governments are...Show moreSubnational climate diplomacy is a concept that has been gaining attention in the field of International Relations in recent years. It refers to the way in which state and local governments are increasingly taking part in international negotiations and cooperation to advance global climate objectives. This signifies a sizable shift in the traditional approach to state-to-state diplomacy. However, the value of subnational climate diplomacy to the global fight against climate change is currently almost exclusively measured in terms of clearly quantifiable outputs, which largely overlooks its less directly quantifiable contributions and broader social, economic and political impacts. Therefore, this thesis analyzes how subnational climate diplomacy can contribute to transformative change through more indirect impacts. The indirect impacts that are measured are ‘rescaling’ and ‘entrenchment,’ based on the frameworks developed by authors van der Ven, Bernstein and Hoffmann (2017) and Setzer (2017). These two concepts serve to guide the analysis undertaken in this thesis, which aims to answer the following research question: How can subnational climate diplomacy contribute to transformative change through rescaling and entrenchment? To answer this question, the thesis includes a detailed case study of the international climate agenda of the U.S. state of California. The analysis of California's international climate agenda shows how the state’s subnational climate diplomacy is contributing to a rescaling of climate governance. By establishing international linkages along both the vertical and the horizontal axis, California is triggering a rescaling of climate governance on the subnational, national and international/supranational level. Additionally, California’s subnational climate diplomacy is fostering entrenchment by generating effects in climate governance that are durable and difficult to reverse. Overall, this study emphasizes that subnational climate diplomacy can contribute to transformative change in global climate governance, not only through producing directly quantifiable emission reductions, but also through rescaling climate governance and entrenching durable change.Show less