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パリ協定の実施やネット・ゼロを目指す自治体や地域の増加を踏まえ、ライフスタイルの転換への注目が高まっている。カーボンフットプリント研究により日本においても製品やサービスの購入を通じた間接排出量がライフサイクルGHG 排出の半分以上を占めることが明らかとなっている。しかし、ライフスタイル及び消費パターンは多様であるため、一国における平均値や合計値だけではこの課題を捉えきれない。国内における消費者間の差に着目した分析が望まれるが、既存研究は世帯人数、収入、年齢に着目した分析が殆どである。本研究では、全国消費実態調査の匿名ミクロデータを用いて日本における約47,000サンプル世帯の一人当たりカーボンフットプリントを推計した。さらに、推計したカーボンフットプリントに関し、高炭素型ライフスタイルの因子分析及び消費者セグメンテーションを行うことにより、多様なライフスタイルを踏まえた日本における家計消費のカーボンフットプリントの特徴を明らかにした。サンプル世帯の製品・サービス群ごとのカーボンフットプリントに関する探索的因子分析により「車のドライブと住居における趣味」「長距離レジャーと社交的消費」等の8つのライフスタイル因子を特定した。さらに、クラスター分析により15の消費者セグメントが特定され、セグメント間で最大5倍程度の差があることが明らかとなった。フットプリントの大きなセグメントは、自動車利用、物質的消費、長距離レジャー、非効率的な住居、小さな世帯人数等の高炭素型ライフスタイルの特徴を複数有していた。本研究のアプローチは、脱炭素型ライフスタイルへの転換を促進するにあたり、消費行動の多様性とその気候変動へのインパクトを把握するために有益である。

Addressing the prevailing mode of high-carbon lifestyles is crucial for the transition towards a net-zero carbon society. Existing studies fail to fully investigate the underlining factors of unsustainable lifestyles beyond individual determinants nor consider the gaps between current footprints and reduction targets. This study examines latent lifestyle factors related to carbon footprints and analyzes gaps between decarbonization targets and current lifestyles of major consumer segments through exploratory factor analysis and cluster analysis. As a case study on Japanese households, it estimates carbon footprints of over 47,000 households using expenditure survey microdata, and identifies high-carbon lifestyle factors and consumer segments by multivariate regression analysis, factor analysis, and cluster analysis. Income, savings, family composition, house size and type, ownership of durables and automobiles, and work style were confirmed as determinants of high-footprint Japanese households, with eight lifestyles factors, including long-distance leisure, materialistic consumption, and meat-rich diets, identified as the main contributory factors. The study revealed a five-fold difference between lowest and highest footprint segments, with all segments overshooting the 2030 and 2050 decarbonization targets. The findings imply the urgent need for policies tailored to diverse consumer segments and to address the underlying causes of high-carbon lifestyles especially of high-carbon segments.

In this study, carbon footprints of households are estimated based on a combination of physical consumption and monetary-based data. Long-term targets for carbon footprints are established based on a review of existing emission scenarios. Hotspots for lifestyle carbon footprints, in nutrition, housing, mobility, and other domains, are identified based on gap analysis with long-term targets. Furthermore, various low-carbon lifestyle options were identified using literature review, and their impacts on footprint reductions have been estimated based on the collected data of physical consumption and carbon intensity. Primary case studies are on Finland and Japan, with supplementary analysis on other countries. The preliminary results revealed the necessity for significant reductions in lifestyle carbon footprints of over 80-90% by 2050, and in major lifestyle hotspots, such as meat and dairy consumption, car and air travel, and fossil-fuel based energy. The reduction potentials from the full and partial adoption of more than 30 low-carbon lifestyle options were evaluated. A comparison of current footprints and potential reductions with long-term reduction targets revealed that very ambitious, urgent actions towards low-carbon shifts of consumer lifestyles are necessary. The results demonstrate that combining physical- with monetary-based data is useful for estimating lifestyle carbon footprints by ensuring both granularity and coverage of estimation, and evaluating potential impacts from lifestyle changes. The findings also suggest the need for further assessment of lifestyle carbon footprints, including hotspot and gap analysis and evaluation of low-carbon options diffeerent countries. The study contributes to a better understanding of the characteristics and potentials of low-carbon consumer lifestyles as an integral part of climate change mitigation, complementing technology-based solutions.

Tämä selvitys perustuu tekniseen raporttiin 1.5-degrees lifestyles: Targets and options for reducing lifestyle carbon footprints (ISBN 978-4-88788-222-5)

This report demonstrates that changes in consumption patterns and dominant lifestyles are a critical and integral part of the solutions package to addressing climate change. The report fills a gap in the existing research by establishing global targets for lifestyle carbon footprints, examining current consumption patterns and their impacts on footprints, and evaluating potential reduction impacts of low-carbon lifestyle options. The results of the analysis are striking, showing in some cases the need for reductions of over 80% in greenhouse gas emissions (GHG) by 2050 from today’s intensity of lifestyles. Reductions will be necessary not only for developed countries; several developing countries will also need to reduce their average per capita emissions from current levels – a significant challenge where the basic needs of large parts of their populations are often still not met. However, as also identified in the report, there are clear opportunities for much needed changes, and these would require that actions start as soon as possible. The report proposes globally unified per capita targets for the carbon footprint from household consumption for the years 2030, 2040 and 2050. It estimates current average carbon footprints of Finland and Japan, as well as Brazil, India, and China, focusing on the comparison of the level of physical consumption in order to be both comparable to global targets and compatible with household-level solutions. It also identifies potential options for reducing lifestyle carbon footprints on the basis of the literature and assesses the impact of such options in Finnish and Japanese contexts. It concludes with suggestions and implications in terms of how to proceed towards lifestyles compatible with the 1.5 °C target. As the report only covers the countries given above, similar studies can be expanded to other countries using the methodology, data sources, and results of estimation that are detailed in Annexes.

The paper describes and analyzes the cooperation of the Sustainable Lifestyles Accelerator with Finnish and Spanish municipalities. The Sustainable Lifestyles Accelerator is a three-year program for upscaling sustainable lifestyles in Finland, Spain, Germany, Switzerland, Denmark, Mexico and India. It is based on the four steps of the transition cycle comprising problem analysis, vision development, experimenting and up-scaling. In the Sustainable Lifestyles Accelerator problem analysis means the calculation of the lifestyle carbon and material footprints of the participating households, vision development the co-creation of individual roadmaps towards 1.5-degree lifestyles by 2030 for each participating household, and experimenting a one-month phase where each participating household tries out several measures out of their roadmap. Up-scaling happens by extending the number of participating households per country from 5-10 in 2018 to 500 in 2019 and 10,000 in 2020. In addition, up-scaling means increasing the number of municipalities cooperating with the Sustainable Lifestyles Accelerator.

This commentary summarises the key findings and implications of the study on Lifestyle Carbon Footprints: Long-term targets and case studies of the carbon footprints of household consumption. This study introduces and develops an approach to establishing lifestyle carbon footprints: greenhouse gases directly emitted during and indirectly induced by household consumption, excluding those induced by government consumption and capital formation. Based on a review of existing emission scenarios, this study proposes globally unified targets for the lifestyle carbon footprint of 2.5 t by 2030, 1.4 t by 2040, and 0.7 tCO2e/cap/year by 2050. These targets are based on 1.5-degree scenarios with limited or no use of negative emission technologies, considering the uncertainty in the availability of these technologies. The estimated total average lifestyle carbon footprints vary considerably among countries. Comparing current levels with GHG emission targets set for 2030 shows that current average lifestyle carbon footprints considerably exceed the targets for Finland and Japan, and slightly exceed those for China and Brazil. These gaps suggest that lifestyle GHG emissions need to decrease in order to achieve the lifestyle carbon footprint target. Out of the consumption domains considered, food, housing, and mobility tend to have the largest impact on total lifestyle carbon footprints.