Japan’s climate policy has experienced significant changes in recent years. Frequent shifts of governments helped bring about various emission reduction pledges. However, only the brief Democratic Party of Japan (DPJ) rule had a truly ambitious policy, but its most ambitious parts were never implemented. A major reason was the 2011 Fukushima Daiichi nuclear disaster, which altered the priorities of Japanese politics. As a result the Liberal Democratic Party (LDP) in 2013 proposed a very modest target, in comparison to other states as well as to previous pledges. However, it should be borne in mind that the costs of reducing emissions in Japan are particularly high because of its high energy efficiency score. Japan has relied primarily on voluntary policies, some of which have been quite effective. Still, the actors demanding a more forceful climate policy are weak and dispersed, whereas the supply-side veto players are strong and concentrated. There are few indications that this is about to change in the near future. Renewable energy cannot expand quickly enough to make up for the shortfall from nuclear power. Thus, if emissions are to be reduced, nuclear power will probably play a more important role than will renewable energy.