Classifying CO₂ Emissions from the Viewpoint of LCA by Reflecting the Influence of Regional Activities

Abstract

After COP3 a lot of countries and even their local governments are struggling to reduce CO₂ emissions. However, the way to define CO₂ emissions is not consistently standardized. In this study we calculate CO2 emissions in two ways: appar-ent and responsible emissions. Apparent CO₂ emissions are caused by the domestic industrial activities and they include CO₂ embodied in exports. Responsible CO₂ emis- sions are attributed to domestic final demand and they include CO₂ embodied in imports. We classify domestic production into that of Tokyo and that of the other regions, and cal-culate regional CO₂ emissions by the above two ways. From the viewpoint of LCA (Life-Cycle Assessment), we utilized the regional input-output table for the database. Apparent and Responsible CO₂ emissions of Tokyo are 17 Mt-C and 32Mt-C, respectively. Because the amount of CO₂ results in such different values, standardizing the way to define CO₂ emissions is a critical problem for deciding the goal of CO₂ reduction. Concerning the emissions in each sector, power generation and transport have the largest reduction potential in industrial sectors. Making the life of buildings longer is the most effective measures from the consumers' viewpoint.