Breaking Free from Linear Thinking: Life Cycle Assessment and Circular Economy

A key theme of the 2017 American Center for Life Cycle Assessment (ACLCA) conference was the need to incorporate circular economy into design principles. Life cycle assessment (LCA) can help identify the areas of a product’s life cycle essential to promoting a circular economy. This appears to be a logical application of LCA principles because, in LCA, the life cycle of a product is often presented as circular like the diagram to the right.

The problem is that this life cycle is not actually circular, it’s linear, and is more accurately depicted like the below:

The current way of thinking about product life cycles is fundamentally linear because there is a raw material extraction phase, a production phase, a use phase and an end-of-life phase. If a life cycle was truly circular, there would be no end-of-life. If there is “final disposal” of a product, such as in a landfill or by incineration, then the system is not circular. Even recycling often results in either downgraded material (referred to as downcycling) or less than 100% of material recycled, which does not represent a perfectly circular economy.

One of the fundamental principles in designing for circular economy is that material waste is avoided by prioritizing end-of-use capture of materials through careful design for things like disassembly, modularity, reuse and upcycling. Circular economy models itself on the natural environment in which nothing is wasted. A plant grows from sunlight and is eaten by an herbivore, which is eaten by a carnivore, which eventually dies and decays to feed fungi, which eventually becomes soil where plant growth can begin again. In nature, there are no landfills.

In fact, if life cycles are truly circular, there would be no raw material extraction. There would simply be the recapture of materials throughout the supply chain and the value chain. Circular economy principles also highlight the ability of organizations to recapture materials through methods like take-back programs that reduce the need to extract new resources.

To move toward circular economy, products must be designed from inception to optimize the ability to recapture materials when the product has completed its first use phase and ensure second, third or even infinite use phases. But how can we do this if the system continues to be analyzed as if it is linear? We can’t. We must reimagine the product life cycle, therefore, reimagine the approach to LCA. The product end-of-life and raw materials extraction phases cannot coexist in a truly circular vision. To break free from this linear thinking, these two phases need to be merged into one phase called “material recovery” to make the depiction of a life cycle cyclical as illustrated in the diagram to the right.

This small step helps shift the perspective on life cycles of products from linear to circular. It also creates a framework for LCA to be prepared to assess and identify the benefits of circular economy. It is the first step toward breaking free of linear thinking and embracing the circular economy. This step is for designers, manufacturers and LCA practitioners alike to apply this shift and be willing to reimagine product life cycles. This small step for designers, manufacturers and LCA practitioners could result in a giant leap toward a more sustainable future.

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