Following neighbors or regional leaders? Unpacking the effect of geographic proximity in local climate policy diffusion

• Published in: Policy sciences Vol. 56; no. 4; pp. 825 - 868
• Main Authors: An, Brian Y., M. Butz, Adam, Cha, Min-Kyeong, Mitchell, Joshua L.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-12-2023; Springer Nature B.V
• Subjects: Cities; Climate policy; Economic Policy; Effects; Environmental policy; Leadership; Local government; Neighbors; Political Science; Political Science and International Relations; Political Science and International Studies; Proximity; Public Administration; Regional variations; Regions; Research Article; Geographically weighted regression (GWR); Geographic neighbors; Regional leadership; Local climate action plan; Policy diffusion
• ISSN: 0032-2687; 1573-0891
• DOI: 10.1007/s11077-023-09499-1

This study examines spatially dynamic diffusion processes of local policy adoption among municipal governments. Using city-level climate action plans (CAPs) adopted in the Southern California region during 2000-2018 as a study frame, our analysis unpacks spatial variations in the effects of geographic neighbors and regional leaders on local policy diffusion processes. We first argue that both factors will spur CAP diffusion among city governments. We then develop a novel hypothesis of a spatial moderating effect between these two influences. Specifically, we theorize that adjacent neighboring diffusion effects will be less prominent in the areas with nearby regional innovators, while neighboring effects will be more prominent in the absence of regional policy leadership. To examine this, we first use traditional event history and logistic regression analyses. We then investigate inter-city diffusion dynamics in greater detail with a novel geographically weighted regression (GWR) method that unravels regional variations in local diffusion effects. Our aggregate analysis finds that both geographic neighbors and regional leaders drive the diffusion of local CAP adoptions. The novel application of GWR further shows marked spatial variations within the region, suggesting that neighboring proximity-driven diffusion effects are muted by the influence of regional leaders. By spatially unpacking the effect of geographic proximity and regional leadership in policy diffusion, this study enhances our understanding of dynamic and varied diffusion processes.