Reevaluating fair carbon emissions for households in Japan: basic energy needs and subsistence CO2 emissions

Substantial inequalities in per capita carbon emissions have recently been highlighted. Given the diversity of people’s energy needs and extant differences in access to low-carbon energy, a fair emissions benchmark would not be equal CO2 emissions for all, but the CO2 emissions needed to enjoy a decent life ('subsistence emissions’). This study investigates the relationship between people’s basic energy needs and associated CO2 emissions, and illustrates the distribution of subsistence emissions among households in Japan, employing a unique and high-visibility technique. It finds that approximately 20% of households cannot meet their basic energy needs with one tonne of CO2 emissions per capita, and that an additional 1.56 million t-CO2 is required for all households to be able to meet their basic energy needs; this additional amount needs to be offset by further emissions reduction by households that consume a lot of domestic energy ('energy extravagant’) or non-residential sectors. With an equal-per-capita distribution of CO2 emissions in line with Japan’s 2030 target, approximately two-thirds of households would not be able to meet their basic energy needs, given the current energy mix and systems. In this context, low-carbon energy and technologies must be made more accessible for vulnerable populations to achieve both decarbonization and satisfaction of basic needs.The method developed in this study evaluates 'fair’ amounts of CO2 emissions ('subsistence emissions’) for households. The results provide essential insights for shaping carbon mitigation strategies, identifying which groups should bear policy burdens and which groups should be exempt.In Japan, two-tenths of households cannot meet basic energy needs with one CO2-t per capita. Carbon mitigation policies need to factor in the differences in people’s energy needs and low-carbon energy access is key to ensuring the inclusiveness of low-carbon energy transitions.Curtailing 'luxury emissions’ and making low-carbon energy and technologies more accessible for vulnerable populations are required for achieving both decarbonization and basic energy needs fulfilment.