LETI

Our current materials economy is linear: materials are mined and extracted from the Earth’s crust, those materials are used to make things, and those things are used, sometimes quite briefly, and ultimately disposed of. We then repeat this process ad infinitum. However, we also know that our planet’s resources and limits are finite. Running this infinitely repeated linear economy model on a finite planet is contributing significantly to multiple planetary crises. The linear economy has led to negative consequences such as human-made climate change, resource depletion, deforestation, habitat loss with resulting biodiversity and bioabundance losses, and environmental pollution of land, air and water.

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The need to transition to a circular model is becoming increasingly urgent. This model values the built environment stocks we have already created far more highly, is regenerative by design, and eliminates the concept of a flow of waste. As one of the largest users of materials, the built environment industry must play a key role in this transition to circularity.

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LETI's Circular Economy Summary provides a definition and explanation of what circularity in a built environment context comprises, with a brand-new diagram to illustrate material flows in the current and future circular built environments. It includes a circular strategies hierarchy, primary actions for the built environment industry to prioritise, and suggests key circularity metrics for professionals to test. The summary also references some areas requiring further attention, namely, the relationship between circularity and whole life carbon reductions as well as the role of biogenic materials in the built environment.

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The LETI Circular Economy Summary is the first publication from the LETI Circular Economy Workstream. This will be followed by a Circular Economy Primer which aims to explore circularity concepts in the built environment in more detail.