the role of policies in fostering sufficiency, although sufficiency is still in conflict with the ideological orientation of many decision-makers who are reluctant to engage with this idea. Policies that are viewed as supportive of sufficiency include: Energy/resource taxation, especially progressive taxation (at a sufficient level to genuinely trigger behaviour change); Personal carbon allowances; Phase-out or restrictions on certain highly intensive energy/resource-based services; Investments in alternative mobility infrastructures (cycling lanes, etc.); Alternative urban planning reducing the need for individual transport means; Facilitating building sharing; Environmental labelling based on absolute product impacts or progressive indicators (i.e. that become more challenging as product size, capacity or features increases); Incentives to encourage sufficiency behaviours and projects, such as financial bonus/malus schemes based on the absolute energy consumption of services; Evolutions in public prescriptions (on comfort, lighting, hygiene…) to alter social norms; Information, communication, and educational campaigns and tools. Limits and challenges The discussion around needs, wants and enoughness As it builds on a sense of self and collective moderation in relation to the consumption of energy and material-based services, sufficiency requires drawing a line between wants seen as superfluous and actual justified needs. It triggers potentially complex and contentious theoretical and practical questions. Answers may differ culturally, change with time and context, as well as depend on income and other socio-economic factors. The issue is not only relevant at the level of individual values, ethics, and lifestyles, but also for public decisions. As an illustration, whereas building or extending an airport was rarely challenged successfully in the past, two recent decisions show this has changed: the decision of the French government to drop the Notre-Dame-des-Landes airport in 2018, and the UK court decision to rule Heathrow’s extension illegal over climate change in 2020. Economic impact Sufficiency supposes a moderation in the consumption and development of high energy-based and material-based services, which are often delivered by or associated with goods and equipment. Thus, sufficiency means limitations on current consumption levels of some products and renouncing some types of infrastructures. A common criticism, shared with the degrowth concept, is that this would hurt economic growth, increase unemployment and lead to social problems. While it is clear that current energy and resource intensive services would be hit by sufficiency, leaner, more local, and employment-intensive activities would also be fostered in the meantime. There is currently limited research on the macroeconomic impacts of a sufficiency-based society. Notably,