Net‐zero carbon declarations by Japanese local governments: What caused the domino‐like diffusion?

Abstract

Sub‐national governments are a crucial non‐state actor for mitigating climate change. This importance has recently strengthened as increasing numbers of municipalities declare net‐zero carbon emission goals to support the Paris Agreement, often well ahead of national governments. In Japan, net‐zero declarations have also diffused widely, with nearly 800 declarations appearing in domino‐like fashion over 2019–2022. To elucidate the factors that propelled this rapid diffusion, we used an event‐history analysis based on data from a survey to develop an integrated statistical model. We then deepen understanding of diffusion mechanisms through seven brief case studies informed by interviews and document analysis. We find that the drivers of policy diffusion varied over time. During the early stage, internal factors drove the spread of declarations; namely participation in transnational city networks, endowed human and financial resources, and political leadership. But in later stages, diffusion was mostly propelled by external factors; namely declarations by neighboring cities and the affiliated prefectural government. Through these findings, we contribute to scholarship through two novel perspectives. First, we reveal the factors driving policy diffusion across both early adopters and the ordinary majority. Second, we show how the influence of well‐known factors can vary during different stages of policy diffusion.

Tackling climate change on the local level: A growing research agenda

“…The findings in this issue show that local communities are actively involved in climate change mitigation under certain circumstances. For example, Nakazawa et al (2023) show that in Japan between 2019 and 2022 net‐zero declarations rapidly diffused across subnational governments. In the beginning, this development was triggered by factors related to the subnational entity, for example, the participation in transnational city networks, endowed human and financial resources, or political leadership.…”

“…The third cluster of frameworks deals with the context of the cities – that is often used in a comparative perspective. With a focus on network effects between the cities and regions, the empirical study by Nakazawa et al (2023) contributes to the literature on policy diffusion (see e.g., Berry & Berry, 2018). Kern et al (2023) draw in their work on the matching cities and scaling approach (see e.g., Kern et al, 2023; van der Heijden, 2022).…”

Network analysis of scientific advisory committee integration in climate change policy: A comparison of Germany and Japan

“…Vertical integration is measured by asking whether SAC members are recruited from diverse sectors. It is repeatedly observed that in the climate policy domain the interests and worldviews are particularly different between economic sectors and environmental groups [23,24], but also between national and local governments [25], and scientists and non-scientists [8]. Securing the chances for actors from various sectors to speak out and listen to others in the SACs is a necessary condition for enhancing EPI.…”