City-level household carbon footprint from purchaser point of view by a modified input-output model

Residential consumption produces carbon emissions through the combustion of primary energy (directly) as well as through the consumption of goods and services (indirectly). To capture the latter indirect emissions, it is common to use producer-price based input-output analysis associated with household monetary expenditures. However, producer-price input-output tables usually do not account for economic transactions and energy flows at the margin. To better understand household indirect emissions from the purchaser perspective, there is a need for a modified input–output modeling approach. To that end, this study attempts to measure the carbon footprint of households in the Tokyo Metropolis, Japan by integrating monthly household consumption inventories into an input–output table of Tokyo. By doing so, the carbon footprint was estimated to be 0.76 tC per household and the total estimated marginal carbon emissions for Tokyo is up to 0.56 MtC. A sectoral breakdown of the total emission coefficients is provided based on purchaser prices and temporal variations in emissions. Findings indicate that within household consumption, Clothing and Services categories contributed most to marginal emissions. The conclusions drawn in this paper are pertinent and policy relevant because they provide relatively accurate information compared to the status quo to inform appropriate policies for guiding residential consumption at the city scale of resolution.