Decomposition analysis of CO2 emission in long-term climate stabilization scenarios

To achieve the stabilization of greenhouse gas (GHG) concentrations in the atmosphere, the international community will need to intensify its long-term efforts. Many EU countries have released national long-term scenarios toward 2050, and their ambitious targets for CO2 emission reduction are aiming at a decrease of more than 50% of todayʹs emission. In April 2004, Japan began a research project on its long-term climate policy. This paper discusses the long-term scenarios in other countries and the medium-term scenarios in Japan to support the development of a Japanʹs long-term climate stabilization scenario. In this study, CO2 emission is decomposed with an extended Kaya identity (indexes: CO2 capture and storage, carbon intensity, energy efficiency, energy intensity, economic activity) and a Reduction Balance Table is developed.In order to achieve the ambitious target of a 60–80% reduction, the pace of aggregated energy intensity improvement and carbon intensity decrease must be 2–3 times greater than the previous 40-year historical change, and the change rates need to be maintained for 50 years.