A circular economy offers solutions for global sustainability challenges through the transition from the linear take-make-use-dispose economy to a better organisation of resources. However, realising a circular economy has ran into various biophysical constraints. Circular economy implementation is shaped by the Ellen MacArthur Foundation's butterfly diagram that depicts 'biological' and 'technical' flows as separate cycles, subsequently interpreted as organic materials circulating in open loop systems via the environment and inorganic materials circulating in closed loop systems within society. Conversely, in our view, resource flows often contain tightly bound combinations of organic and inorganic materials either due to their natural composition or due to their technical design. Building on this observation, a new diagram is proposed that broadens the scope of the circular economy to cover extractive sectors and the return of materials from anthropogenic use to natural reserves, thereby reshaping the conceptual space within which solutions such as effective zero-waste-residue technologies, business models, and policies can be developed for the optimal management of integrated resources from a whole-system perspective. The diagram offers a realistic outlook on the biophysical limitations of circularity and endeavours to inspire discussion that supports the transition towards a sustainable circular economy.

People altered the biophysical environment upon which they depend through the overexploitation of resources and growing waste generation. Action is urgently needed to return the resource economy within planetary boundaries and safeguard human well-being, by realising an increasingly closed-loop system that maintains values of materials and products within a sustainable circular economy. Innovative technologies and business models must be developed and implemented, requiring convincing "business cases" for industry and government; why should they be interested in adopting circular, resource recovery practices? Despite multi-dimensional challenges facing people and their environment, and the ability of resource recovery to contribute to restoring environment, society and economy, arguments for circular practices are often overly focused on economic aspects. Economic growth is not a panacea and this article supports the preparation of better arguments by presenting expert insights on 37 themes to consider for a resource recovery business case. The most important themes cover 1) Economic, social, environmental and technical value of resources and 2) Regulatory change; focusing business cases on these is likely to deliver positive impacts regarding all identified themes. The article synthesises the old "growth will solve it-" with a new "multi-dimensional challenges and solutions" paradigm, suggesting that resource recovery should support multi-dimensional growth to partly redistribute economic benefits to social and environmental values through the preservation of technical, functional value of materials and products. Writing successful business cases for resource recovery requires inter-disciplinary collaboration, and sustained effort to complete and translate business cases into measurable impacts through changed practices outside academia.

Current societal patterns of production and consumption drive a twin environmental crisis of resource scarcity and waste overload. Positioning waste and resource management in the context of ecosystem stewardship, this article relates increasing resource demand and waste production to the violation of planetary boundaries and human rights. We argue that a transition towards a circular economy (CE) that contributes to a resilient environment and human well-being is necessary to achieve the UN Sustainable Development Goals. The transition requires scientific and technological progress, including the development of low-energy biogeochemical technologies for resource recovery, and multi-dimensional value assessment tools integrating environmental, social, and economic factors. While the urgency to adopt a CE is well-recognised, progress has been slow. Coordinated change is required from multiple actors across society. Academia can contribute through participatory action research. This article concludes with the participation strategy of the Resource Recovery from Waste programme, aiming for changes in mentality, industry practices, and policies and regulations in the waste and resource management landscape in the UK.