Measuring the waste footprint of cities in Japan : a interregional waste input–output analysis

Metropolitan regions, which are typically planned without considering aspects related to sustainability, tend to depend on neighboring regions for their waste treatment, particularly for the disposal of solid waste in landfills. The repercussion effects of consumption in metropolitan regions may bring about economic benefits. However, quantitative assessments of the interregional relationships between the metropolitan areas and the other regions are necessary in order to clarify whether the undesirable environmental loads incurred by the surrounding regions are outweighed by economic benefits. In this study, we clarified the repercussion effects of consumption by metropolitan residents on production and environmental loads by examining the utilization of landfill sites in these other regions using interregional waste input-output (IRWIO) analysis. Specifically, we investigated the effects of consumption activities in Tokyo, and compiled an IRWIO table for Tokyo in the year 2000. Using this table, we then estimated the effects of landfill utilization in Tokyo and other regions, as well as the associated induced economic and environmental impacts. The results showed that consumption in Tokyo induced limited economic benefits and large-scale utilization of landfills in other regions. Although consumption by Tokyo residents induced an increase in the recycling of municipal solid waste (MSW), thus reducing the amount of waste to be treated in other regions, the total amount of induced landfill volume was 1.7 million cubic meter, which is 2.4 times greater than that of Tokyo. The results quantitatively clarified the repercussion effects associated with consumption by residents in metropolitan areas and illustrated the importance of sustainable waste management to stakeholders, particularly those in metropolitan regions.