Exploring spatial explicit greenhouse gas inventories: Location-based accounting approach and implications in Japan

Cities are both the main source of greenhouse gases (GHGs) and the main arena of emission reductions. However, many cities have difficulties to compile the GHG inventories to support their mitigation plans and actions scientifically. Currently, the IPCC framework of inventories is mostly sector-based, within which the emission from a certain sector is estimated as an aggregated volume based on statistical yearbooks. Since the data is only available above some administration level, emissions are difficult to scale down to a specific geographical boundary. With this circumstance, a spatial explicit accounting approach on the city-level GHG inventory is required to provide sophisticated information for the better decision-making on the local mitigation actions. The aim of this study is to propose a location-based GHG inventory approach to fill the gap. The proposed inventory framework uses sampling surveys, enterprise GHG reports and the geo-referenced data to estimate the emissions and the spatial distributions. Geographic Information Systems (GIS) are used to integrate the results. The proposed framework is applied to Oita Prefecture, Japan as an implication to test the approach's feasibility and offering enlightening insights. Since the emission sources are visible on maps and one can zoom to any necessary level of scale, the location-based inventory can better provide the spatial explicit information for better mitigation policy-making and environmental education at community levels. It will also provide enlightening insights to the in-depth investigation on the relationships between distribution of GHG emissions and the city landscapes, hence benefitting the low-carbon city research and practice in the future.