Geospatial extent of CO2 emission of transportation and the impact of decarbonization policy in Japan

Abstract

Decarbonization policies have been increasingly implemented worldwide to mitigate the impacts of climate change in the transportation sector. It is therefore crucial to understand the effect of these policies on the transportation mode choice decisions made by shippers and the overall utilization of intermodal networks. This study aims to explore the impact of decarbonization policies on the intermodal transportation network as well as shippers’ consciousness towards CO2 reduction on the spatial transition of port hinterlands in Japan. The study seeks to determine the combination of policies, such as carbon pricing and subsidies, that are likely to result in higher volumes of freight traffic at local ports. Therefore, we developed a Monte Carlo algorithm-based intermodal network model to examine the effect of decarbonization policies on the domestic freight flow among livelihood spheres to utilize the spatial transition of port hinterlands. In this study, we (i) visualized the port hinterland transition pattern, freight volume and emission diffusion pattern among intermodal links due to decarbonization policies geospatially; (ii) built a nationwide intermodal network model based on Monte Carlo algorithm; (iii) applied the developed model to intermodal transport network with multiple origin-destinations, and to generate a variance-covariance matrix among transportation routes dynamically. We conducted two scenario analyses by using a developed model. The results revealed that the improvement of shippers' consciousness and the increase of carbon taxes are not likely to lead to modal shift or attraction of port utilization, but rather a shift to railway, which has the lowest carbon dioxide emissions. It can be concluded that further promotions or incentives are necessary to revitalize local ports and waterways. This study can benefit policymakers, transport planners, and port authorities by providing actionable insights into designing effective decarbonization strategies. The findings offer guidance on modal shifts and enhancing the utilization of low-carbon transport networks to achieve sustainable logistics in Japan.