Innovating in sub-national climate policy: the mandatory emissions reduction scheme in Tokyo

This study analyses the drivers behind the policy-making and implementation of the recently developed climate policies in the Tokyo Metropolitan Government (TMG). In 2010, the TMG introduced a mandatory CO2 emission reduction and a cap-and-trade scheme; the world's first such scheme that sets binding targets for buildings. The research was carried out through reviews of the published and unpublished literature, surveys and face-to-face interviews with various stakeholders involved in the policy process. The essential components that enabled successful policy-making and implementation of the scheme in Tokyo are revealed, such as the administrative leadership and the capacity of the TMG administration, the availability of historical data supporting the policy discussions and the gradual and flexible implementation mechanisms. The article concludes with recommendations for future improvements in the TMG and beyond.Policy relevanceThis article presents the lessons from the recent advancements in climate policy in Tokyo, particularly the world's first mandatory city-scale emission reduction and cap-and-trade scheme that includes buildings. The scheme was relatively effective as the total GHG emissions were reduced by 23% on average from the base years and 10% below the average of other parts of the country before the end of the first compliance period of five years (2010–2014). The policy innovations from the world's largest city and the capital of Japan can inform sub-national governments about the potential barriers and opportunities for introducing mandatory GHG emissions reductions.