National and subnational outcomes of waste management policies for 1718 municipalities in Japan: development of a bottom-up waste flow model and its application to a declining population through 2030

Japan has been promoting 3R (reduce, reuse, and recycle) policies for several decades, but the recycling rate of the whole country has leveled off, and more effective policies are needed. At the same time, municipalities have been implementing measures for municipal waste management considering their specific regional conditions, but the relationship between the municipalities’ policy inputs and national policy output is unclear, which causes difficulties in setting national targets and identifying effective policies. We, therefore, developed the Municipal Input and National Output Waste (MINOWA) model, which represents the municipal waste flows of all 1718 municipalities in Japan. The model enables users to establish various 3R measures at the municipal level and estimate their effects at the national level. Using the model, we estimated the flows under business-as-usual (BaU) and additional-measure scenarios that extended the use of conventional policies to 2030. The results revealed differences in the policy effects between areas with different populations. In addition, the results showed that the extension of conventional measures will be insufficient to achieve national goals. The developed model links municipal policies, regional characteristics, and national policy and goal-setting in an integrated framework, and supports ways to find more effective policies.