Dynamic Policy Diffusion in the Metropolis: Unpacking Spatial and Ideological Dimensions of Local Climate Policy Adoption in Southern California

Abstract

This study examines the dynamic diffusion processes of local policy adoption among the city governments in Southern California. Using climate change policy as a study frame, our analysis unpacks the spatial and ideological dimensions of the local policy diffusion process. Specifically, we theorize how the diffusion effects of geographic neighbors and ideological peers on the likelihood of a focal city's policy adoption vary geographically across jurisdictions. We first use traditional Event History Analysis to examine the aggregate effects of geographic neighbors and ideological peers in the diffusion process. We then investigate the inter-jurisdictional diffusion dynamics in further detail, using a novel Geographically Weighted Regression technique to unravel the local effects that vary by individual jurisdictions. We find that geographic neighbors drive the diffusion process of local climate policy adoptions, while ideologically similar peers do not. The application of Geographically Weighted Regression further indicates that some municipalities are influenced strongly by adjacent neighbors, while others respond to more geographically distant policy adopters. These results are consistent with our original hypothesis, which posits how local jurisdictions may differentially respond to the diffusion process in the presence and absence of nearby regional leaders and favorable governing climate for the policy enactment. Future studies should consider evaluating the spatially dynamic diffusion processes occurring across jurisdictions for different policies and political jurisdictions.