Decomposing Vehicle Production and Consumption Impacts in Japan under Mobility and Production Network Interventions

Abstract

Passenger vehicles contribute approximately 8% to global energy-related emissions and drive other environmental impacts through the extraction of raw materials. In this study, a hybrid LCA approach is used to investigate emissions and material life-cycle impacts arising from vehicle production and consumption in Japan. By embedding a physical vehicle production model within a global MRIO, we find that 53% of emissions occur in Japan, while almost all material extraction impacts occur internationally. Vehicle size, PHEV utility factor, and battery capacity all strongly influence life-cycle impacts. Demand-side scenarios of increased occupancy, downsizing, and lifetime extension have the collective potential to reduce emissions by approximately 33% at the cohort level, while providing comparable mobility services. Lifetime extension requires additional material inputs with associated impacts; however, these impacts are repaid over time, resulting in an overall average emissions intensity (gCO2e/km) reduction of 7%. Vehicle electrification alone is unlikely to be sufficient to meet climate targets; therefore, demand-side measures should be implemented concurrently to decarbonize passenger transport while maintaining access to mobility services. While some opportunity exists to substitute upstream suppliers for lower-impact providers, the existence of low-pollution production havens is limited, further underscoring the importance of demand-side measures.