Evaluation of CO2 Emission Reduction in Japan Utilizing the Interregional Repercussion Model on Freight Transportation

This study proposes a novel method of input-output analysis for physical distribution, with applications in the evaluation of potential reductions in CO2 emissions. Using the "Physical Distribution Census" published by the National Land and Transportation Ministry in Japan, methods of calculating physical distribution induced by a unit of final demand and physical distribution derived by a unit of production are developed. Induced and/or derived CO2 emissions are directly calculated from the induced and/or derived physical distribution. This allows analysis of the interregional relationship that combines physical distribution with either industrial production or household consumption. A case study of derived physical distribution shows that a ton of final demand of farm and marine products in Tokyo and Hokkaido generates CO2 emissions of 62 kg and 31 kg, respectively. As an application of this method, potential for CO2 reduction was evaluated by considering a modal shift from truck transportation to rail and marine transportation. A 50 % modal shift was found to achieve a 990 Mt reduction in CO2 emissions. In a case study for the induced physical distribution method, a ton of farm and marine products produced in Hokkaido was found to generate 2.5 tons of interregional physical distribution. This method was applied by evaluating the potential increase in CO2 emissions that would be caused by an improvement in the rate of food self-sufficiency. The results indicate that more than one million tons of CO2 could be further emitted due to a five-percentage point improvement in Japan's self-sufficiency rate.