•  332 papers on automobile LCA were reviewed using a meta-analysis.
• Our review characterized automobile LCA studies by the statistical comparison to life cycle CO2 emissions of gasoline and diesel vehicles, hybrid vehicles, electric vehicles, and fuel cell vehicles.
• The current status of automobile LCA research and the limitations were clarified from the perspectives of globalization in automobile life cycle, social expansion in new automobile technology, country diversity in automobile usage, and country factor in battery degradation of electric vehicle.
• The direction of automobile LCA research as a communication tool for "design of sustainable social systems" from "environmental impact assessment of automobile-related technologies" was presented.

The key considerations for advanced life cycle assessment (LCA) of automobiles leading to a sustainable society are globalization in automobile life cycle (globalization), social expansion in new automobile technology (social expansion), country diversity in automobile usage (country diversity), and country factor in battery degradation of electric vehicle (battery degradation).

This study comprehensively reviewed automobile LCA studies using a meta-analysis approach. This approach was applied to 332 peer-reviewed papers with cross aggregate and statistical analysis. This review results found the high uncertainty of the environmental impact assessment results of electric vehicles from the statistical comparison of life cycle CO2 emissions of gasoline and diesel vehicles, hybrid vehicles, electric vehicles, and fuel cell vehicles. The current status of automobile LCA research and the limitations were clarified from the perspectives of globalization, social expansion, country diversity, and battery degradation. Furthermore, this study indicated the direction of automobile LCA research as the communication tool for "design of sustainable social systems" from "environmental impact assessment of automobile-related technologies".

Source: H. Oda, H. Noguchi, M. Fuse, Review of life cycle assessment for automobiles: A meta-analysis-based approach, Renewable and Sustainable Energy Reviews, 159:112214, 2022.