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As the global flow of advanced architecturalmaterials grows with the expanding globaleconomy, and as even traditional dwellings

built with local materials begin to put pressure onnatural resources in developing countries, envi-ronmental policy makers, business leaders andgovernments worldwide are increasingly embrac-ing energy and material efficiency to mitigate theimpacts of architecture.

But perhaps eco-efficiency’s moment has past.“Doing more with less” played a valuable role inslowing ecological destruction in the late 20th cen-tury, but it is not up to the challenges presentedby the kind of growth and global change expectedin the 21st.

Certainly, eco-efficient measures such as theEuropean Union’s national targets for energy andmaterial efficiency are laudable attempts to sus-

tain human health and economic growth. Butusing less fuel to heat energy-efficient highrises orsending less building material to landfills does notaddress the deep flaws of contemporary architec-ture and industry; it simply limits the negativeimpact of poor design.

The result, an easing of ecological stress, hasbeen an important step towards a more just andhealthful world. But it is yesterday’s step. The timehas come to adopt a truly hopeful strategy thatwill solve rather than merely alleviate the prob-lems associated with buildings and construction, astrategy that will transform architecture into a cel-ebration of a human ecological footprint withwholly positive effects.

Yesterday’s ecological footprintTo move towards a sustaining, life-supportinghuman footprint, it is worthwhile to take a closelook at the ideas and practices informing sustain-able architecture today. The realization that con-ventional, modern architecture is not sustainableover the long term is not new. Constructing andmaintaining new buildings rivals the global econ-omy’s entire manufacturing sector in material andenergy use. For over a decade UNEP and otherinternational bodies, along with an expanding net-work of NGOs, have been striving to shift the pri-orities of governments, businesses and architectstowards more environmentally sound practices.

But how effective are the typical approaches todesign for sustainability? Most are aimed at usingenergy and material more efficiently, a strategythat grows from the idea that decoupling materi-al use from economic growth can sustain archi-tecture and industry over the long term. Thiswould seem to be a critical insight. A report by theWorld Resources Institute projects a 300% rise inenergy and material use as world population andeconomic activity increase over the next 50 years.As long as economic growth implies increasedmaterial use, it warns, “there is little hope of lim-iting the impacts of human activity on the natur-al environment.” But, the report continues, ifindustry can become more efficient, using lessmaterial to provide the goods and services peoplewant, economic growth can be sustained – andthus decoupled from resource extraction and envi-ronmental harm.1

The same study found, however, that despite 25years of dematerialization by five of the world’s

Towards a sustaining architecture for the 21st century: the promise of cradle-to-cradle design

William McDonough, William McDonough + Partners, Architecture and Community Design, 410 E. Water Street, Charlottesville, Virginia 22902, USA

(wmp@mcdonough.com).

Michael Braungart, EPEA Internationale Umweltforschung GmbH, Feldstrasse 36, 20357 Hamburg, Germany (epea@epea.com)

SummaryCradle-to-cradle design is an ecologically intelligent approach to architecture and industrythat involves materials, buildings and patterns of settlement which are wholly healthful andrestorative. Unlike cradle-to-grave systems, cradle-to-cradle design sees human systems asnutrient cycles in which every material can support life. Materials designed as biological nutri-ents provide nourishment for nature after use; technical nutrients circulate through industrialsystems in closed-loop cycles of production, recovery and remanufacture. Following a science-based protocol for selecting safe, healthful ingredients, cradle-to-cradle design maximizes theutility of material assets. Responding to physical, cultural and climactic settings, it createsbuildings and community plans that generate a diverse range of economic, social and eco-logical value in industrialized and developing countries.

RésuméLes méthodes de conception qui envisagent un produit depuis sa production jusqu’à la valori-sation de ses résidus constituent une approche écologiquement intelligente de l’architecture etde l’industrie qui créent des matériaux, des bâtiments et des modèles d’établissement par-faitement sains et stimulants. Contrairement aux méthodes dites « de bout en bout », ellesconsidèrent les systèmes humains comme des cycles de substances nutritives où chaque matéri-au a un rôle à jouer dans le maintien de la vie. Les matériaux étudiés comme des substancesnutritives biologiques servent de nourriture à la nature après usage ; les substances nutritivestechniques circulent dans les systèmes industriels selon des cycles de production, de valorisa-tion et de reconditionnement à boucle fermée. Respectant un protocole à fondements scien-tifiques pour sélectionner des ingrédients présentant une totale innocuité et bons pour la santé,les méthodes de conception qui envisagent le produit depuis sa production jusqu’à la valori-sation de ses résidus renforcent le potentiel des ressources en matériaux. Adaptées au contextephysique, culturel et climatique, elles créent des bâtiments et des projets d’intérêt collectifgénérateurs de valeurs économiques, sociales et écologiques, dans les pays industrialiséscomme dans les pays en développement.

ResumenEl diseño “cradle to cradle” (múltiples ciclos de vida) es un planteamiento ecológico inteligentede la arquitectura y la industria que crea materiales, edificios y patrones de asentamiento total-mente sanos y reparadores. Diferente de los sistemas “cradle to grave” (ciclo de vida único),el diseño “cradle to cradle” considera los sistemas humanos como ciclos nutrientes en los quecada material puede sustentar la vida. Los materiales diseñados como nutrientes biológicosproveen alimento para la naturaleza después de ser utilizados. Los nutrientes técnicos circulanen sistemas industriales en ciclos cerrados de producción, recuperación y remanufactura. Sigu-iendo un protocolo establecido sobre bases científicas para seleccionar ingredientes seguros ysanos, el diseño “cradle to cradle” aprovecha al máximo la utilidad de los valores materiales.De acuerdo al medio físico, cultural o climático, crea edificios y planes comunitarios que gen-eran una amplia gama de valores económicos, sociales y ecológicos tanto en naciones indus-trializadas como en países en desarrollo.

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most potent economies, waste and pollution inthose nations had increased by as much as 28%.Though many European nations in the past tenyears have achieved significant reductions inwaste, they are merely reaching for sustainability,which is, after all, only a minimum condition forsurvival.

It is true that efficiently constructed buildingscan cut waste, and that lighter materials can min-imize resource consumption. But while designersmay make material substitutions – super-efficientglass, triple glazing, recycled plastic – the chem-istry of materials in efficient buildings tends to bethe same as that in their more gluttonous con-temporaries. And that still presents a serious threatto human health.

Materials and human healthIndeed, none of the materials used to make con-temporary buildings is specifically designed to behealthful for people. Even a cursory inventorybegins to suggest some of the challenges facingarchitects.

Consider the ubiquitous use of polyvinyl chlo-ride. Better known as PVC or vinyl, it is com-monly used for windows, doors, siding, flooring,wall coverings, interior surfaces and insulation.Many PVC formulations contain plasticizers andtoxic heavy metals such as cadmium and lead.Plasticizers are suspected of disrupting humanendocrine systems, cadmium is known to be car-cinogenic, and lead is a neurotoxin.

Equally common are the volatile organic com-pounds, some of which are suspected carcinogensand immune system disruptors, which are releasedfrom particleboard, paints, textiles, adhesives andcarpets. Design flaws that trap moisture in build-ings and add mould to the substances foulingindoor air, as well as the products developed tofight mould, appear to be generating a permanentbreeding ground for resistant microorganisms.The widespread presence of wood preservativesand lead rounds out this formidable array ofharmful materials.

Energy efficient buildings, which are designedto require less heating and cooling, and thus lessair circulation, can make things worse. A recentstudy in Germany found that air quality insideseveral highly rated energy efficient buildings indowntown Hamburg was nearly four times worsethan on the dirty, car-clogged street.2 For all thecare taken to save energy by keeping out the ele-ments with better insulation and sealed windows,no one considered the long-term effects of sealingin the chemically laden carpets, upholsteries,paints and adhesives used to finish the interiors.

The effects are hard to ignore. When buildingswith reduced air-exchange rates are common, soare health problems. In Germany, where tax cred-its support the construction of energy efficientbuildings, allergies affect 42% of children aged sixto seven, largely due to the poor quality of indoorair.3

Eco-efficient buildings also have a culturalimpact. Following the old modernist aesthetic,they tend to be steel and glass boxes short on freshair and natural light, their internal ecosystems

divorced from their surroundings. Whether locat-ed in Frankfurt or Indonesia, they are the same.Architecture critic James Howard Kunstler hascalled such structures “intrinsically despotic build-ings that [make] people feel placeless, powerless,insignificant, and less than human.”4

Are these the kind of buildings we want all overthe world? Can’t we do better?

Cradle-to-cradle designWe can. Cradle-to cradle design raises an entirelydifferent agenda. Rather than seeing materials as awaste management problem, as in the cradle-to-grave system, cradle-to-cradle design is based on theclosed-loop nutrient cycles of nature, in which thereis no waste. By modelling human designs on theseregenerative cycles, cradle-to-cradle design seeks,from the start, to create buildings, communitiesand systems that generate wholly positive effects onhuman and environmental health. Not less wasteand fewer negative effects, but more positive effects.Imagine, for example, buildings that make oxygen,sequester carbon, fix nitrogen, distill water, providehabitat for thousands of species, accrue solar ener-gy as fuel, build soil, create microclimate, changewith the seasons, and are beautiful.

One need not simply imagine such places. Byclearly understanding the chemistry of naturalprocesses and their interactions with human pur-pose, architects can create buildings that aredelightful, productive and regenerative by design.This represents a radical shift: from inanimate,one-size-fits-all structures into which we plugpower and largely toxic materials, to buildings aslife-support systems embedded in the materialand energy flows of particular places. The pres-ence of such buildings around the world suggeststhat human activity can indeed create footprintsto delight in rather than lament.

This is not just wishful thinking or “concept”design. The cradle-to-cradle philosophy is drivinga growing movement devoted to developing safematerials, products, supply chains and manufac-turing processes throughout architecture andindustry. It is being adopted by some of theworld’s most influential corporations, includingBASF, the world’s largest chemical company;Shaw Industries, the world’s largest carpet maker;Ford Motor and its major suppliers in the autoindustry; and a host of prestigious designers andmanufacturers of textiles, furniture and otherobjects. Even in nations as vast and influential asChina, organizations such as the China-US Cen-ter for Sustainable Development are adopting thisnew paradigm to develop healthful buildings, safeindustrial processes and sustainable communityplans.

Here’s why. Cradle-to-cradle design is animatedby ecological intelligence. In the natural world – agrand, evolving system based on hundreds of mil-lions of years of research and development – theprocesses of each organism contribute to thehealth of the whole. One organism’s waste is foodfor another, and nutrients and energy flow per-petually in closed-loop cycles of growth, decayand rebirth. Waste equals food. Understandingthis natural system allows architects and designers

to recognize that all materials can be seen as nutri-ents that flow in natural or designed metabolisms.

Nature’s nutrient cycles comprise the biologicalmetabolism. The technical metabolism is designedto mirror the Earth’s cradle-to-cradle cycles; it’s aclosed-loop system in which valuable, high-techsynthetics and mineral resources circulate in anendless cycle of production, recovery and reuse.

By specifying safe, healthful ingredients,designers and architects can create and use mate-rials within cradle-to-cradle cycles. Materialsdesigned as biological nutrients, such as textiles fordraperies, wall coverings and upholstery, can bedesigned to biodegrade safely and restore soil afteruse, generating more positive effects, not fewernegative ones. Materials designed as technicalnutrients, such as infinitely recyclable textiles, canprovide high-quality, high-tech ingredients forgeneration after generation of synthetic products.And buildings constructed with these nutritiousmaterials, and designed to respond to local energyflows and cultural settings, encourage patterns ofhuman settlement that are restorative and regen-erative.

Waste equals food: fromdematerialization to rematerializationCradle-to-cradle design yields an entirely newrelationship to materials, energy and the makingof things. Where eco-efficient designs aim todematerialize – minimizing the negative effects oftoxic materials and polluting fuels – cradle-to-cra-dle design seeks the rematerialization of safe, pro-ductive materials in systems powered by the sun.

Rematerialization can be understood as both aprocess and a metaphor. In the industrial world itrefers to chemical recycling that adds value tomaterials, allowing them to be used again andagain in high-quality products. As a metaphorgrowing from this process, it suggests a designstrategy aimed at maximizing the positive effectsof materials and energy and participating in theEarth’s abundant material flows.

Nylon 6 provides a good example of remateri-alization. This widely used polymer can be chem-ically recycled into the raw material caprolactam,which can be used to make generation after gen-eration of high-quality carpet fibre. In effect, theprocess virtually eliminates waste – very little ener-gy or material is lost. Given the hundreds of mil-lions of pounds of carpet fibre that each year aresent to landfills or incinerators or recycled intoproducts of lesser value, the significance of rema-terializing nylon 6 is enormous. And it suggests aneffective new model for material flows.

The model is changing real-world business.Shaw Industries, for example, has examined thematerial chemistry of its carpet fibre and backingto assess the healthfulness of its dyes, pigments,finishes and auxiliaries – everything that goes intocarpet tile. Out of this rigorous process has comethe promise of a fully optimized technical nutri-ent. Shaw now guarantees that all its nylon 6 car-pet fibre will be taken back and returned to nylon6 fibre, and its safe polyolefin backing returned tosafe polyolefin backing.

Rematerialization makes conventional recycling

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look obsolete. Most recycling is actually downcy-cling, a loss of value over time with materials losingvalue. When various plastics are recycled intocountertops, for example, valuable materials aremixed and can’t be recycled again. New ultra-lightcomposite materials are hybrids from the start;they can’t even be recycled once. And when metalssuch as copper, nickel and manganese are blendedin recycling, their value is lost forever.

The key to effective rematerialization is defin-ing material chemistry and tracking materialflows. A materials passport – a tracking code cre-ated with molecular markers, for example – makesthat possible. The passport guides materialsthrough industrial cycles, routing them from pro-duction through reuse, defining optimum usesand intelligent practices. With a passport, valu-able construction materials can be rematerializedinto valuable construction materials, not recycledinto hybrids of lesser value heading inexorablytowards the landfill.

When conceived as nutrients, high-tech mate-rials can be safely and effectively used in everyphase of construction. Cradle-to-cradle geopoly-mers, for example, are a promising replacementfor concrete, which leaches harmful chemicals onbuilding sites and in landfills. Made from localearth and high-quality plastic, geopolymers are farmore stable than concrete and require far lessembodied energy to produce. Design for disas-sembly allows building materials made ofgeopolymers to be used again in new buildings.Or they can be returned to technical cycles andused in other high-quality products. Anothermaterial designed as a technical nutrient, a poly-styrene foam engineered by BASF, is being devel-oped as a structural material for low-cost housingin developing countries.

Safe biological nutrients can be used through-out interiors, generating healthful effects duringproduction and use and even after they wear out.

A textile we designed, woven of wool and ramieand processed with completely safe chemicals,provides an attractive, healthful upholstery fabricand can nourish the soil when it wears out. At theSwiss mill where the fabric is produced, the trim-mings serve as garden mulch. The water leavingthe factory is as clean as the water flowing in.

Rematerialization and cradle-to-cradle designcan be applied with high-tech or low-tech meth-ods to new or existing buildings. Harmful materi-als in existing buildings can be replaced withhealthful ones. Old buildings can also be restoredwith new designs and technologies that harvestthe sun’s energy – examples include the AudubonSociety’s century-old headquarters in Manhattanand the venerable Field Museum in Chicago – orflexibly refitted for a variety of new uses.

Intelligent materials poolingRematerialization on a large scale can be achievedthrough a nutrient management system we callintelligent materials pooling. This system,designed to effectively manage flows of polymers,rare minerals and high-tech materials for industryand architecture as well as local, low-tech flows ofnatural resources, calls for cooperative networksgeared to optimizing materials’ value.

In an intelligent materials pool, multiple com-panies share access to a supply of a high-qualitymaterial such as nylon 6 or copper. In effect, part-ners draw materials from the pool to create prod-ucts and replenish it with materials they haverecovered after a defined period of use. Sharingresources and knowledge, information and pur-chasing power, partners in a materials pool ideal-ly develop a shared commitment to generating ahealthy system of material flows and to using thesafest, highest-quality technical ingredients in alltheir products.

From a strategic perspective, the process beginswith an agreement by several companies to phase

out an environmentally dangerous material suchas PVC. Out of this shared commitment comes acommunity of companies with the marketstrength to engineer the phase-out and developinnovative alternatives. Together they specify pre-ferred materials, establish defined-use periods forproducts and services, and create an intelligentmaterials pool.

Design and the laws of natureCradle-to-cradle architectural materials realizetheir full potential within cradle-to-cradle build-ings. The context of material use is always the larg-er design, and the larger design always unfolds inthe overarching context of the natural world.

Cradle-to-cradle building design is thus theprocess of discovering beneficial, fitting ways forhumans to inhabit the landscape. In every land-scape, nature is our guide. We study landforms,hydrology, vegetation and climate, trying tounderstand all the natural systems at play in eachplace we work. We investigate environmental andcultural history, study local energy flows, andexplore the cycles of sunlight, shade and water.Out of these investigations comes an “essay ofclues” – a map for developing healthy and cre-atively interactive relationships between ourdesigns and the natural world.

The sun is the key to the whole show. Whensunlight shines upon the Earth, biology flourish-es and we celebrate its increase – the growth oftrees, plants, food and biodiversity. This is goodgrowth. When human activity supports ecologi-cal health, that’s good growth, too. In fact, we cancreate buildings that make the energy of the sun apart of our metabolism, allowing us to tap theeffectiveness of natural systems and apply archi-tecture to positive purpose.

At Oberlin College, William McDonough +Partners (WM+P) designed a building like a tree:a building powered by the sun, enmeshed in local

The roof of 901 Cherry (offices of Gap, Inc.) recreates the native habitat of grasses and wild flowers. Its form derives from the surrounding landscape. © William McDonough + Partners

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nutrient flows and beneficial to the landscape.Built in northern Ohio, the Adam Joseph LewisCenter for Environmental Studies was designedto ultimately generate more energy than it con-sumes. Solar power is collected with rooftop cellsand sunlight pours through southwest-facing win-dows into a two-story atrium, illuminating thepublic gathering areas. Wastewater is purified by aconstructed marsh-like ecosystem that breaksdown and digests organic material and releasesclean water. The upholstery fabrics will feed thegarden, and the carpets will be retrieved by themanufacturer and reused for new, high-qualitycarpets.

Lit by the sun, refreshed with fragrant breezes,in tune with its place through local flows of ener-gy and matter, the Oberlin building’s ecologicalfootprint strongly confirms that the human pres-ence in the landscape can be positive, restorativeand 100% good.

Cradle-to-cradle economicsCradle-to-cradle design also makes extraordinari-ly good sense economically and socially. This isespecially visible in the workplace. When designsfor large-scale factories and offices are modelledon nature’s effectiveness, they generate delightful,productive places for people to work. This notonly encourages a strong sense of community andcooperation, it also allows efficiency and cost-effectiveness to serve a larger purpose.

Consider the corporate offices for Gap, Inc. inSan Bruno, California. Aiming to enhance thequalities of the local landscape, WM+P designedan undulating roof covered in flowers and grassesthat mirrors the local terrain, re-establishing sev-eral acres of the coastal savannah ecosystem thathad been destroyed by human intervention overthe past century. The living roof also absorbsstorm water and provides thermal insulation,making the landscape an integral part of the build-ing’s energy systems.

Other features maximize local energy flows. Araised-floor air system allows evening breezes toflush the building, while concrete slabs beneaththe floor store the cool air and release it during theday. The windows are operable and the delivery offresh air is under individual control. Daylightingprovides natural illumination. This is an opendesign with common spaces.

The building’s advanced integrated systems areso effective, it was recognized as one of the mostenergy efficient buildings in California. By aim-ing to maximize positive effects, the design out-performed buildings that set efficiency as theirhighest goal.

The building’s high performance is replicable.The Herman Miller furniture factory in Holland,Michigan, like the Gap building, was designed to

foster a spirit of community among employeeswhile enhancing the local environment. An effec-tive, celebratory design achieved both – and more.Not only did the building’s site plan includeextensive constructed wetlands that rebuild soilfabric, provide habitat and purify storm water, butits design, which maximizes fresh air and sunlight,generated increased worker satisfaction and pro-ductivity gains of 24%. Corporations locating indeveloping countries might take note: designingfor human and environmental health supportseconomic productivity.

Cradle-to-cradle planningThe benefits of cradle-to-cradle design are notlimited to individual buildings. In Chicago, whereMayor Richard Daley is on a quest to make thecity the greenest in America, cradle-to-cradle prin-ciples are providing an inspiring reference pointfor a host of citywide initiatives. Building on yearsof innovative environmental programmes, theCity of Chicago is now developing communityplans and cradle-to-cradle systems that will makeit an international model for cities seeking designsthat allow industry and ecology, human settle-ments and the natural world to flourish side byside.

Among many other initiatives, Chicago hasagreed to buy 20% of its power from renewablesources by 2006, which is spurring the local devel-opment of renewable energy technology. Indeed,some renewable energy companies have movedinto the city’s new Chicago Center for GreenTechnology, an ecologically-intelligent facilitybuilt on a restored industrial site. Looking ahead,we see Chicago becoming a hub of green manu-facturing and transit, energy effectiveness, envi-ronmental restoration and cradle-to-cradlematerial flows – all of which adds up to flourishinghuman communities that generate an abundanceof ecological, economic and cultural wealth.

Cradle-to-cradle systems can generate thiswide spectrum of wealth worldwide, in industri-alized and developing nations alike. In ruralChina the people of Huangbaiyu, led by localentrepreneur Dai Xiaolong, are developing a Cra-dle-to-Cradle Village that aspires to be poweredby the sun, with all materials maintained inclosed-loop technical and biological cycles.

Significantly, the Cradle-to-Cradle Village isnot an idea being imposed on Huangbaiyu by theChinese government or by an international aidagency; it was generated by Mr. Dai’s enterprisingleadership, which has drawn support from TongJi University in Shanghai, the China-US Centerfor Sustainable Development, and WM+P. Mr.Dai’s plan is based on investing in and growingHuangbaiyu’s existing capacity to become moreeconomically self-reliant and regenerative. The

chairman of the Tianyuan Eco-Cattle Farm, a suc-cessful business with subsidiary companies thatinclude a brewery, breeding farm, organic fertiliz-er factory and trout fishery, Mr. Dai is well versedin nature’s cradle-to-cradle systems and is apply-ing them to the Huangbaiyu community devel-opment plan.

This plan is centred on the building of a com-pact settlement which will make maximum use ofHuangbaiyu’s available agricultural land, generateoptimal conditions for closed-loop material flows,and provide services and amenities that cannot beeffectively furnished to a dispersed population.Local workers will employ straw bale constructionto build the village’s 300 homes, taking advantageof an essentially free local material with proveninsulating capacity. A community well will pro-vide clean running water, a resource typically inshort supply. Human and animal waste will becollected at centralized locations and used to pro-duce biogas, which will in turn be used for heatingand cooking. There will be street trees, publicparks and a village school. The people of Huang-baiyu will be steadily employed in a variety of localenterprises, from sustainable forestry to farmingto working in the biogas faciltity or a wood prod-ucts plant. The enduring cycles of nature, it ishoped, will generate a wide spectrum of commu-nity wealth.

A diversity of sustaining cradle-to-cradle visionscould come to fruition in many places. Fromhigh-tech Chicago to rural China, from Japanesetemples to American factories, the principles andpractices of cradle-to-cradle design are already cre-ating hopeful changes in the world. Ultimately,we believe intelligent design can lead to ever morebuildings, communities, cities and nations thathonour not just human ingenuity but harmonywith the exquisite intelligence of nature. Whenthat becomes the hallmark of good design, we willhave entered a moment in human history whenthe things we make will truly be a regenerativeforce.

Notes1. Matthews, Emily, et al. (2000) The Weight ofNations: Material Outflows From IndustrialEconomies. World Resources Institute, Washing-ton, D.C.2. Bujanowski, Anke, Michael Braungart andChristian Sinn (1998) Primitives Produktdesign.Müllmagazin, 2, pp. 24-26.3. Braungart, Michael, Anke Bujanowski, JürgenSchäding and Christian Sinn (1997) Poor DesignPractices – Gaseous Emissions from Complex Prod-ucts. Hamburger Umweltintitut e.V., p. 9.4. Kunstler, James Howard (2001) The City inMind: Notes on the Urban Condition. Free Press,New York. ◆