Consider the cherry tree. A frenetic supply chain of blossom that produces thousands of seeds in the hope that one might fall to the soil, take root and grow. Its manufacturing model is inefficient, wasteful and laborious, yet beautifully nourishing to its surrounding ecology. The blossom that do not germinate instead provide nutrients for insects, microorganisms, animals and soil; its abundance and over-production should not be chastised, but celebrated. In Michael Braungart and William McDonough’s seminal book “Cradle-to-Cradle: Remaking the Way We Make Things”, the author’s ask: “What would the human-built world look like if it were built by a cherry tree?”. Braungart and McDonaugh assert that since the industrial revolution, humankind’s marriage with nature has been shaky and is now, in the 21st century, going through a messy, complicated divorce.

The authors argue that our conventional cradle-to-grave manufacturing and consumption processes are deeply flawed in their linearity and their contempt they show for the environment. They compel the reader to drive a personal and corporate paradigm shift toward a circular design economy – their so-called cradle-to-cradle (C2C) approach. Their manifesto for revolution asks that producers make three actions: one is to see waste as food for the environment; two is to separate biological and technical nutrients in products to ease ready recycling and upcycling; and three is to adopt eco-effective practices rather than eco-efficient practices that value and incorporate the environment in design. Central to the novel’s argument is the author’s criticism of western society’s obsession with death, indeed graves. They suggest that mankind is fixated on finding a grave for their products after their finite and often short useful life. Braungart and McDonough summarise their circular philosophy and set up their narrative by asking the reader “what if the industrial revolution had taken place in a society that believed in reincarnation? Would our cradle-to-grave approach become cradle-to-cradle?”

The concept of circularity was first discussed 52 years ago when Kenneth Boudling began questioning the linear openness of our economic activity in his piece “The Economics of the Coming Spaceship Earth” [1]. He identified society’s predisposition toward sending material to ‘sinks’ rather than reusing them in a closed economy. In 1989, this idea was further developed by Pearce and Kerry Turner when they first coined the phrase ‘circular economy’ [2], after which Jackson synthesised much of the work in the field in his book “Material Concerns: Pollution, profit and quality of life” [3]. Thought toward bettering our products by copying natural design in the form of biomimicry was first discussed in 1982 by Merrill [4], before being popularised by Benyus in her seminal book “Biomimicry: Innovation Inspired by Nature” [5]. Cradle-to-Cradle’s call for ecological practice in industry and a closer alignment with nature draws heavily on these influences and preaches the author’s sermon in accessible English that resonates with academics, corporations and the public. In response to Cradle-to-Cradle, the Ellen Macarthur Foundation have furthered the shift toward a circular economy by producing a realisable framework that is founded on Braungart and McDonough’s cradle-to-cradle principles. The book has been cited thousands of times and has sold more than 300,000 copies worldwide. As such, it must be credited with starting a revolution in industrial design and in public discourse around societal overconsumption and waste.

Cradle-to-Cradle comments on various aspects of sustainability, notably: challenging orthodoxy through change, operating within environmental limits and enacting effective life cycle management. The novel-spanning motif that we must create a mindset shift toward waste equalling food is the clearest objection of orthodoxy. The authors are constantly challenging the idea of waste describing it as an artefact of human creation; “whatever humans make does not go ‘away’” they exclaim. They make the reader question where “away” really is; is a landfill “away”? Is a recycling plant “away”? Where is this abstract place? They emphasise that nothing enters or leaves the confines of our planet, thus we live in materially closed system. Braungart and McDonough state that “to eliminate the concept of waste means to design things – products, packaging and systems – from the very beginning on the understanding that waste does not exist”. Inoculating public and corporate minds with this message could be extremely powerful in catalysing the transition toward a sustainable circular economy and I believe this is the most influential, effective message from the book. The author’s exemplars of how we can make our waste nourishing and not damaging are often idealistic, particularly their assertion that we should design a car with clean water as effluent that could promote roadside ecology. Despite their head-in-the-clouds aspirations, I still feel this message is truly valuable. I would add that any efforts to shift the paradigm away from convention will inevitably seem utopic at first, but it is only by thinking laterally with great optimism that can we enact real change.

Throughout the text, Braungart and McDonaugh ask industry to design processes and products that operate within the environmental limits of the planet. They repeatedly remind the reader that “being less-bad is not good” referring to the environmental impact of our actions. They demonise so-called eco-efficiency, that is, for example: using less material in manufacturing, creating more carbon-efficient processes or using less water in agriculture. To that end, McDonough was quoted in an interview with the National Press Club as saying “If you want to go to Mexico, and you’re driving toward Canada, even if you slow down you’re still going to Canada”. Instead the authors ask the reader: “What would it mean to be 100% good?”, by that they mean operating with eco-effectiveness; designing systems so they are in deep symbiosis with nature. In doing so they say we can strive for a future of abundance, rather than one of limited eco-efficiency, bounded by the traditional environmentalist ideals of conservationism. The authors claim that their eco-effective principles will design systems that “pay back […] the environment with interest” and in my opinion this is where, their argument collapses.

Despite the authors giving thought to environmentalism at a systems level, I am not convinced the boundaries of their analysis are wide enough, and this particular utopic view is a clear example. It is thermodynamically impossible for a process to pay back the environment “with interest”, this would require it to add more energy to the environment than was taken in the first place. Sure, creating coffee cups that require few inputs to produce and can fertilise farmland when disposed would be excellent, and I welcome the innovation that cracks this perpetual motion-style problem, but these are impossibilities.

The author’s character assassination on eco-efficiency seems equally misguided. They state that we should build eco-effective buildings with green roofs that provide bird habitat and solar cooling, rather than designing more efficient air-conditioning systems or effective solar shades. Whilst I agree that green roofs bring positive benefits, the authors do not comment on the increased structural steel required to buttress these green roofs. What about the mineral extraction associated with this added steel? The carbon emissions produced in their manufacturing? The disposal of this steel at the building’s end of life? The bounds of their systems analysis appear blinkered. “Efficiency isn’t much fun” McDonough and Braungart assert. I would argue efficiency can be fun, as well as challenging and beneficial despite not paying back the environment with circular idealism. Strangely, the authors backtrack on their criticism of efficiency, concluding their comments by saying “This is not to condemn all efficiency. When implemented as a tool within a larger, effective system […] efficiency can actually be valuable”. Their lack of continuity in this argument is a damning indictment of their eco-effective propaganda.

Life cycle management is a third sustainability theme tackled by McDonough and Braungart’s Cradle-to-Cradle. They describe two component metabolisms from which products are formed: the biological cycle and the technical cycle, and they say that extending the useful life of a product is achieved by optimising products within these cycles. The biological metabolism consists of biological nutrients; materials that can be “consumed by microorganisms in the soil and by other animals”. Conversely, the technical metabolism is filled with technical nutrients that are man-made materials; industrial components. The authors suggest that we must keep these cycles entirely separate if we are to salvage and reuse components in new products. If we do not, we create products they describe as “monstrous hybrids”. McDonough and Braungart describe the modern leather shoe as a monstrous hybrid. Leather is, of course, a biological nutrient that would traditionally be coloured with a vegetable chemical: tannis. Recently, leather shoes have been coloured with chromium tanning, a technical nutrient, to avoid the energy-intensive process of extracting tannis from trees. Because these nutrients become intrinsically locked together, neither component can be salvaged at their end of use and their value is lost. I believe this analysis is extremely valuable in an engineering context as it requires that life cycle thinking is at the forefront of the designer’s mind at the earliest stage of a project, rather than an afterthought.

The authors use this analogy to comment on recycling, or a lack thereof, in industry more generally. They introduce the concept of “downcycling”, whereby valuable components are not reused in their original context, but downgraded to a rudimentary form; plastic water bottles are often melted down and moulded into speed bumps, for example. The authors tell the reader that separating the biological and technical metabolisms will in fact enable upcycling, whereby components can be used in applications better than their original use. What a wonderful idea! Components can be used again and again in ever-improving contexts. I struggle with this concept and find, once again, the boundaries of their system are conveniently limited. Thermodynamics is their recurring enemy, with the second law stating that everything tends toward disorder. Upcycling components to higher quality contexts, contexts of higher order, requires the input of energy – a distinct omission from their analysis. The recycling system becomes tricky when you consider the second law as all matter is freefalling into a cavernous well of disorder. In my opinion, we should strive for recycling in the same context rather than upcycling, but even this requires an energy input to maintain the same order or quality. I think it is unrealistic and uneconomic to expect that technical nutrients can be transformed to applications of higher quality – a practice that any corporate executive would endorse if he thought it were plausible – and believe it comes at the detriment to the authors otherwise effective observations on life cycle management.

Braungart and McDonough’s Cradle-to-Cradle is a seminal piece in the sustainability field that undoubtedly inspired the circularity movement and highlighted the wasteful consumption paradigm that plagues society. Their call for the reader to take inspiration from nature’s waste-free, abundant supply chains is effective as is their observations of the technical and biological metabolisms that contribute to our products. The author’s often utopic philosophies seem tricky to implement and their analyses appear limited, but their optimism about the future is refreshing in a world filled with negative rhetoric. A true strength of their message is the coherent language through which it is delivered, but I would argue that, despite the book’s accessibility, there are very few readers who can realistically enact the change they want. This power is inherently reserved for political leaders and captains of industry and their message offers few hand-holds for the general public to grip to. Nevertheless, Cradle-to-Cradle is an overwhelmingly positive contribution to sustainable thought that opens a dialogue with all stakeholders of the design process. If the cherry tree represents the ideal to which we aspire, Michael Braungart and William McDonough have planted the first seeds.


[1] K. E. Boulding, “The Economics of the Coming Spaceship Earth,” Environ. Qual. Grow. Econ., pp. 3–14, Mar. 1966.

[2] D. W. Pearce and R. Kerry Turner, Economics of Natural Resources and the Environment. 1989.

[3] T. Jackson, Material Concerns: Pollution, profit and quality of life. Routledge, 1996.

[4] C. L. Merrill, “Biomimicry of the Dioxygen Active Site In The Copper Proteins Hemocyanin and Cytochrome Oxidase,” Thesis, 1982.

[5] J. Benyus, Biomimicry: Innovation Inspired by Nature. William Morrow & Company, Inc., 1997.