There is a growing recognition of the urgent need to change citizens’ lifestyles to realise decarbonised societies. Consumption-based accounting (carbon footprinting) is a helpful indicator for measuring the impacts of peoples’ consumption on climate change by capturing both direct and embedded carbon emissions. However, while carbon footprinting can propose impactful behaviour changes to reduce carbon footprints immediately, it may deflect people’s attention from the much needed but time-consuming efforts to reshape the “systems of provisions” to enable decarbonised living. To propose a more constructive application of carbon footprinting, the paper examines the three cases of using carbon footprinting derived from the 1.5-degree lifestyles project, including citizens’ discussions and experiments in six cities in 2020 and 2021, citizens’ workshops contributing to the local policy development in 2022, and lectures and mini-workshops since 2020. Based on the examination of the cases, the article argues the broader purposes of using scientific data in citizens’ engagement in climate actions, namely to help deepen understanding of the systemic causes of the incumbent carbon-intensive society, to guide discussions on the desired conditional changes to support lifestyles shifts, and to help identify possible risks or negative consequences of changes to specific groups in society. These benefits contribute to developing relevant stakeholders’ essential capacities to promote changes at the individual, collective and public levels toward decarbonised societies.

Information and Communication Technologies (ICT) have been identified as potential enablers for alternative forms of sharing surplus food to prevent food loss and waste. Food sharing platforms can also provide an entry point to the sustainability transition by encouraging its users to confront the systemic causes of unsustainable and inequitable food systems. The paper explores the opportunities and challenges of ICT-mediated food sharing platforms in Japan. A comparative case study of 10 food sharing platforms operating in Japan was drawn from a web content analysis and semi-structured interviews. A consumer-side analysis was conducted, based on a Japan-wide survey of 10,000 respondents, to understand consumers’ general attitudes towards ICT-mediated food sharing and identify key challenges and drivers for its expansion. This paper provides initial contributions to understanding the Japanese experience of ICT-mediated food sharing from both the supply and consumption sides. All investigated food sharing platforms embedded food waste reduction and sustainable objectives in their mission. However, a consumer-side survey suggests that participation in food sharing was mainly driven by price consciousness and convenience orientation. Distrust towards the safety of redistributed food and reluctance to engage in a sharing community were some of the main barriers identified to food sharing. Highlighting convergences and divergences between platforms and consumers was key to starting developing intervention designs towards expanding online food sharing and leading consumers’ behaviour change.

Recent studies have highlighted the significant role of lifestyle changes in achieving climate change targets. However, implementing substantial changes in people’s lifestyles is challenging due to the varying availability of goods and services and the influence of the surrounding environment. To address this challenge and promote low-carbon and decarbonised lifestyles on a societal scale, a two-week household experiment was conducted in four representative Japanese cities (Kyoto, Yokohama, Kitakyushu, and Kagoshima). The experiment was based on 65 carbon reduction/mitigation options proposed in previous studies. A total of 84 participants participated in the household experiments: 29 in Kyoto, 22 in Yokohama, 12 in Kitakyushu, and 21 in Kagoshima. Due to constraints imposed by the COVID-19 pandemic, implementation was monitored through a ‘household experiment diary’. The household experiments examined the status of implementation of each option and assessed the potential for improvement over a short period. Furthermore, the study identified barriers, enabling contexts and proposed support measures for implementing household mitigation actions. This study also provided policy implications for co-creating decarbonised lifestyles.