Circularity and sustainability - these terms are used together and somewhat interchangeably, which is unfortunately confusing and dilutes the importance and value of the actions related to either one. This page provides an explanation of how these terms are used, and why. Circularity and sustainability are differentiated, but this is not to judge one as better than the other. The goal here is to communicate more explicitly how the two terms relate to each other, as well as to help new organizations see more clearly how and where they can be a part of the system.
Consider Sustainability (capitalized) as an umbrella consisting of the vision set out by the Brundtland Report: "Sustainable development is development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Any activity or process that strives to meet this vision has a place under this umbrella.
Moving from vision to implementation, though, the space under the umbrella gets crowded. The practice of sustainability (not capitalized) is grounded in and focused on the biosphere – the left-hand side of the now-famous “butterfly diagram” presented by the Ellen MacArthur Foundation. It evolved from the fields of ecology and environmental science, which gave sustainability the holistic, systems-based view so crucial to successful programs in this space, but is also biased towards natural systems. Circular systems do exist here – such as the carbon cycle, nitrogen cycle, water cycle, or even full ecosystems - contributing to confusion around what should be considered “circular.” However, food, water, and other materials in this space will cycle regardless of what we do as a species.
The practice of circularity is focused on and grounded in the technosphere - a human construct designed to support the conversion of raw materials for human consumption beyond simple survival needs of food and water. The intentional design of a system is what separates circularity from sustainability. Cycling materials in the technosphere needs to be part of the design, since it is not something that happens without intervention. Circularity and the circular economy address this lack of cycling and define a clear place “under the umbrella” about how to manage the transition.
The biosphere and technosphere do not exist fully independent of each other and pieces of one have been adapted to solve challenges in the other (e.g., bio-based plastics in the technosphere or synthetic fertilizers in the biosphere). In the Circular Economy Toolbox, we have included “sustainability” tags on projects in this Toolbox that encompass elements of circularity and sustainability. By making visible how we communicate about these topics, we hope to foster a greater appreciation and understanding of all activities under the Sustainability umbrella.