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Joint Japan-UK research has revealed that rapid demographic changes—population aging together with the increase in single-person households—pose structural risks for both decarbonization and energy sufficiency. Addressing this challenge will require the redesign of cross-sectoral policies extending beyond climate and energy policies alone, encompassing housing, urban, and social policy.

Tsukuba, Japan—In Japan, alongside rapid population aging, the number of older adults living alone is increasing. This research analyzed how such demographic changes influence household energy requirements, carbon dioxide (CO₂) emissions, and the financial burden of domestic energy, using data from the two developed countries, Japan and the United Kingdom.

The analysis showed that in both countries, older single-person households tend to have higher per-capita domestic energy use and CO₂ emissions, as well as heavier energy-cost burdens. These patterns can be explained by several factors: older adults spend more time at home and have greater heating and cooling needs; and smaller households cannot use energy services as efficiently as larger households.

These dual demographic trends—population aging and the growth of single‑person households—not only threaten decarbonization progress but also elevate the risk of energy poverty, in which households cannot meet their basic energy needs. In short, the growing prevalence of older adults living alone can create serious structural risks to future fair energy transitions, with significant implications for both environmental sustainability and people's wellbeing.

Addressing this challenge will require integrated policy initiatives encompassing not only energy and environmental policy but also housing, urban, and social policy. This study will provide essential insights for considering new directions in environmental and energy policy in the context of future demographic trends.

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This study was funded by the Grant-in-Aid for Scientific Research (JSPSKAKENHI) [Grant No. JP21H03667/JP23K21782] and by the Kajima Foundation's Researcher Exchange Support.

Original Paper

Title of original paper:

Aging alone: a twin threat to decarbonisation and energy vulnerability in Japan and UK

Journal:

Energy Policy

DOI:

10.1016/j.enpol.2026.115155

Correspondence

Professor OKUSHIMA Shinichiro
Institute of Systems and Information Engineering, University of Tsukuba

Related Link

Institute of Systems and Information Engineering