also designates the societal transformations (in terms of lifestyles, social practices, infrastructures, etc.) that will be necessary to bring production and consumption patterns to a level compatible with the goal. It raises the question of individual and social limitations on these current patterns, building in particular on a sense of ‘enoughness’. The term sufficiency has been popularised by Thomas Princen’s book ‘The Logic of Sufficiency’ published in 2005, in which he argues that ‘seeking enough when more is possible is both intuitive and rational - personally, organizationally and ecologically. And under global ecological constraint, it is ethical.’ Sufficiency may be approached at individual level as a personal attitude or life philosophy (such as in the ‘Sobriété heureuse’ concept of French environmentalist Pierre Rabhi, or Schneidewind‘s concept of the ‘Good Life’), as well as a core collective value that could amend the notion of liberal societies. Sufficiency can be interpreted and discussed in virtually all social settings and economic sectors. In terms of lifestyles, it is strongly related to the concepts of voluntary simplicity and downshifting. Energy sufficiency The concept of sufficiency has been primarily developed in the area of energy consumption, where levels of greenhouse gas emissions far exceed what the planet may absorb and “rapid, far-reaching and unprecedented changes in all aspects of society” are necessary according to IPCC. Drawing on the limits of technical efficiency and rebound effects, sufficiency proponents argue that energy demand and its associated emissions cannot be sufficiently reduced if the root causes of this demand are not addressed, that is the nature and level of the energy services our societies rely on. In that prospect, energy sufficiency is about questioning and drastically reducing energy demand through ‘changes in quantity or quality’ of the energy-based services consumed, notably by ‘favouring behaviours and activities that are intrinsically low on energy use’. The boundary between efficiency and sufficiency actions are not always precisely set; some authors have a broad conception of efficiency that may include aspects of lifestyle change. Academic work released in 2022 systematically classified and databased specific public policy measures that can, individually and collectively, contribute to the uptake energy sufficiency. Contents under Creative Commons CC‑BY‑4.0 licensing. Material sufficiency Sufficiency is also applicable to material consumption. Similar to energy sufficiency, it consists in reducing demand for services and activities requiring high level of material resources, and favouring intrinsically lean ones. It is for instance associated