Since 1971, Tochigi Prefecture has measured sulfur oxide emitted from the Ashio Smelter, and at several points emissions have exceeded environmental standards. In 1968, an Ashio residents group submitted a petition to the town council seeking compensation for smoke damage/injury. Subsequently in 1969, they conducted a questionnaire survey about health hazards and other issues. However, no epidemiological surveys or lawsuits followed. This paper analyzes the attitudes of the residents group and the town administration using the “issue-attention cycle” to help explain this process. After the submission of reports by the residents group, the town administration simply asked residents to submit “evidence” of damage or injury. However, the epidemiological survey that was to serve as “evidence” became an obstacle. More precisely, the town administration abandoned its role to protect the health of the residents. Meanwhile, the company’s business in the town deteriorated. In order to make a living, residents had to avoid surveys that would result in them being personally identified by the company. Therefore, an epidemiological survey was not conducted, residents did not speak out, and, as a result, health hazards were not identified.

In domestic and international negotiations on climate change mitigation measures, it is required to quantitatively assess the effects and impacts of measures, and the role of model analysis and prediction for this purpose has increased over the past three decades. In this paper, we review the scientific findings from IPCC/AR6 that have been elucidated by global mitigation assessment models, review the development of mitigation assessment models in Japan, and summarize their contributions to considerations regarding reduction targets and policies at the national level and to planning at the local level. As future research challenges, we point out the need to take into account aspects of society, culture, institutions, and behavioral change that have not been actively incorporated into mitigation measure assessment models, and to incorporate findings by sectoral, theoretical, and empirical studies.