Multi-regional input–output analysis of the relationship between environmental footprints and the import dependence of Japanese prefectures

Abstract

This study examined the proposition that a subnational region with a low dependence on an external supply of goods and services has low environmental impacts based on consumption-based accounting. Thus, we investigated the relationship between the level of economic dependence of Japanese prefectures on domestic and international imports of goods and services and the environmental footprints (EFs) of their households. EFs were calculated for greenhouse gas (GHG) emissions and use of land, water, and materials using datasets for the year 2015. We estimated the EFs through an environmentally extended input–output analysis using multi-regional input–output datasets, EXIOBASE3. We conducted linear regression analyses of the prefectural household EFs with their socioeconomic, demographic, and geographical factors, including import ratios representing the import dependence of prefectures. The results indicated that the prefectures with a low import ratio, all other factors being equal, had low indirect GHG, land, water, and material footprints. In addition, we found that food and food-related consumptions were dominant contributors to these footprints. When the GHG emissions from household fuel combustion, electricity use and household waste incineration were included in the GHG footprint, the emissions from household energy use were the largest contributor to the footprint. The results indicate that substituting locally sourced foodstuffs and renewable energy for internationally imported food products and non-renewable energy/fuels could reduce multiple environmental impacts of households in the prefectures.