A circular economy is an economic system that minimizes the use of raw materials and the generation of waste. Materials are reused and recycled to maximize their lifetime, and social and economic benefits, approximating a sustainable closed loop system.
From Linear to Circular
A circular economy offers an alternative to the linear “take, make, and dispose” economy. In a linear economy, materials are extracted, transformed into products with a limited lifespan, then discarded and thrown away whereas in a circular economy, materials are kept in use.
Assistant Professor at University College London
Former Postdoctoral Associate and Lecturer at Yale Center for Industrial Ecology
A Strategy for Sustainability
The circular economy is intended to provide an actionable framework for governments and businesses to pursue sustainability goals. However, a shift to a circular economy is not easy: it requires fundamental systemic changes in the design, marketing, use, and end-of-life waste management of products. This, in turn, requires profound changes in education and training, business models, and government policy.
Goals of Circular Economy
The circular economy is often viewed in the context of sustainable development, which promises better lives for people today without compromising the wellbeing of future generations. Sustainable development emphasizes environmental quality, economic prosperity, and social equity. Most circular economy thinkers focus on prosperity and the environment, but increasingly also pay attention to equity and wellbeing.
A circular economy builds on the 3 “Rs”: reduce, reuse, and recycle.
A longer list of “Rs” is shown to the right which lists ten different activities, from the top priority of reducing consumption to the last resort of energy recovery from waste. 
History of Circular Economy
The basic concepts of resource management that inform a circular economy, such as sharing and conservation, go back thousands of years. The modern formulation of the circular economy concept is more recent. For example, in a 1969 essay, the American economist Kenneth Boulding presented a “spaceman economy”. Boulding imagined the world economy as a spaceship with limited resources, in which “all outputs from consumption would constantly be recycled to become inputs for production.” Circular economy is derived from the field of industrial ecology and the concepts of biomimicry, cradle-to-cradle, and regenerative design. Inspirations for the circular economy include the blue economy, green economy, and the performance economy. The circular economy keeps developing but is also subject to criticism. Can it truly deliver on its economic, environmental, and social promise? Or should we look beyond economic growth for more radical models? 
The UK-based charity Ellen MacArthur foundation has played a major role in raising the profile of the circular economy concept. In this video, they explain the concept:
The circular economy promises to address a variety of challenges. Its popularity is at least partly explained by concerns over dwindling global finite resources, geopolitical struggles over scarce materials, low economic growth in industrialized nations, and the environmental impacts of production and consumption, including climate change.
Circular Economy: A Systems Approach
A circular economy operates at different systemic levels, often defined as the macro, meso, and micro levels.
Government, city, region, nation, the economic system more broadly
Eco-industrial parks, clusters of companies working in close proximity
Products, individual companies, consumers
What's next for the Circular Economy?
Circular Economy is a relatively new term with a wide array of users, including academics, governments, businesses, and other agencies. This widespread adoption is positive because it has spurred action that would not have happened otherwise. However, one downside with such a rapid and wide rise in popularity is the lack of clarity of what Circular Economy means and what its main objectives are.
Sustainable development or greenwashing? Not everyone has the same objectives in mind when talking about the circular economy - how to avoid circular economy becoming (another) meaningless marketing term?
What about the social impacts of the circular economy? Circular economy thinkers are increasingly considering equity and circularity. Economic and environmental benefits are great, but where and for whom?
Can we really go beyond our current lifestyles? How realistic is a massive shift in consumer mindset and behavior from a culture of materialism and convenience to sharing and reusing?
Circulation of materials - recycling in particular - still requires energy and generates environmental impacts. How much circularity is enough? Can we keep consuming more and more when consumption is circular?
The circular economy concept suggests that economic growth and environmental protection are ultimately compatible. Is this realistic? What about going slow instead of circular? Can and should we focus less on economic growth? 
 Julian Kirchherr, Denise Reike, Marko Hekkert, Conceptualizing the circular economy: An analysis of 114 definitions, Resources, Conservation and Recycling, Volume 127, 2017, Pages 221-232, ISSN 0921-3449, https://doi.org/10.1016/j.resconrec.2017.09.005.
 Martin Calisto Friant, Walter J.V. Vermeulen, Roberta Salomone, A typology of circular economy discourses: Navigating the diverse visions of a contested paradigm,Resources, Conservation and Recycling, Volume 161, 2020,04917, ISSN 0921-3449 https://doi.org/10.1016/j.resconrec.2020.104917.
 Corvellec, H, Stowell, A, Johansson, N. Critiques of the circular economy. J Ind Ecol. 2021; 1– 12. https://doi.org/10.1111/jiec.13187