The four major factors confronting Japan’s efforts to prioritize global climate change (GCC) as an international commitment in its domestic politics involve: energy security, the political party in power, domestic public opinion, and the state of the economy. In recent years Japan has taken on a robust role in advocating for acknowledging and for addressing the challenges of GCC in its foreign policy and for providing development assistance. This chapter also addresses the influence of the US on Japan’s GCC policy. Japan’s GCC policies have been shaped by its post-World War II history of economic modernization and the environmental challenges these developments presented, where domestic politics had to respond to public demands over profound water and air pollution concerns. The contributions Japan has made to the ongoing formation of the UNFCCC regime have been significant. Yet, this chapter notes that Japan has not been able to escape its long struggle with its geography and its exposure to natural disasters. Japan’s efforts to pursue an international agenda centered on human security for addressing GCC may be undercut by the more state security attributes that stem from a lack of non-carbon-based alternatives to nuclear energy and its continuing concerns over its economic growth.