Revealing the life cycle greenhouse gas emissions of materials: The Japanese case

Double decoupling of economic growth with resource use amounts and resource use with generated environmental effects has been recognized as a policy objective towards sustainability by the European commission. To achieve such a policy, indicators are needed to establish the specific environmental of materials from a life cycle perspective. To date, only environmentally weighted material consumption (EMC) indicators have been created to meet this objective. However, current developments of EMC restrain its application mainly to finished materials because of the risk of double counting occurring when considering resources and semi-finished materials supply chains. Furthermore, statistics availability is often cited as an obstacle to develop EMC analysis further. The present work presents strong improvements of the EMC concept and provides calculation methods to avoid double counting issues and to determine the life cycle environmental effects of materials of all types distinguishing between upstream effects linked to the production of materials and downstream effects linked to the use of these materials. The new methodology has been applied to the Japanese case considering 64 target resource materials among the 393 sectors available in the 2011 Japanese IO table and domestically emitted GHG emissions. Ten materials (crude steel, petroleum refinery product, cement, paper, rice, marine fishery, dairy cattle farming, aliphatic intermediated, vegetables and rice) were identified as accounting for more than three quarters of the total greenhouse gas emissions and should therefore constitute the priority of emission management and decoupling policies.