Channels of Policy Diffusion and Upscaling: Insights from Municipal Climate Change Adaptation Policy in Germany

Policy diffusion and upscaling have become popular governance approaches to promote the spread of public policy, particularly where coercive means are unavailable or undesirable, including in climate policy. However, the channels via which policies diffuse and are upscaled are not well understood given ongoing conceptual and empirical uncertainties. The present study combines insights from policy diffusion and upscaling with governance principles to distinguish between five different policy diffusion and upscaling channels. We probe these channels studying municipal climate change adaptation policy in the state of Hessen in central Germany using novel survey data and a new policy measure that distinguishes between the institutionalization of adaptation and concrete measures. The results indicate that the spread of local adaptation institutions such as plans and new staff positions is mainly linked with financed and coordinated upscaling channels, i.e. funding programs and municipal climate networks established by higher levels of government. The adoption of concrete adaptation measures, however, is rather linked with autonomous diffusion, i.e. “informal” exchange between municipalities, and persuasive upscaling, i.e. the provision of information by higher levels of government. The results advance our understanding of policy diffusion and upscaling and how to support municipal adaptation to climate change.