DECLARATIONS FOR NET-ZERO BY 2050 AS A TURNING POINT FOR CLIMATE POLICY: LINKAGES BETWEEN VERTICAL AND HORIZONTAL DIFFUSION

Abstract

 This article examines the diffusion of net-zero declarations across Japan, elucidating the mechanisms that drove what can be considered a turning point in domestic climate policy. Based on theory from the literature on policy diffusion, we carry out a case study on Kanagawa Prefecture to investigate the dynamic process by which mutual interactions across national and sub-national governments, horizontal diffusion across city government drove the diffusion of net-zero targets across Japan. We also verify the effect of transnational networks along with other drivers and barriers. Using data from semi-structured interviews and document analysis, we find that adoption of the net-zero target began with progressive cities belonging to transnational networks. After this trend was noticed and promoted by the Ministry of the Environment, the increase of declarations at the sub-national then spurred the adoption of a net-zero target by the national government, which further propelled the emergence of net-zero declarations across Japan’s municipalities.