Imagine a world in which all the things we make, use, and consume provide nutrition for nature and industry—a world in which growth is good and human activity generates a delightful, restorative ecological footprint.

While this may seem like heresy to many in the world of sustainable development, the destructive qualities of today’s cradle-to-grave industrial system can be seen as the result of a fundamental design problem, not the inevitable outcome of consumption and economic activity. Indeed, good design—principled design based on the laws of nature—can transform the making and consumption of things into a regenerative force.

This new conception of design—known as cradle-to-cradle design—goes beyond retrofitting industrial systems to reduce their harm. Conventional approaches to sustainability often make the efficient use of energy and materials their ultimate goal. While this can be a useful transitional strategy, it tends to reduce negative impacts without transforming harmful activity. Recycling carpet, for example, might reduce consumption, but if the attached carpet backing contains PVC, which most carpet backing does, the recycled product is still on a one-way trip to the landfill, where it becomes hazardous waste.

Cradle-to-cradle design, on the other hand, offers a framework in which the effective, regenerative cycles of nature provide models for wholly positive human designs. Within this framework we can create economies that purify air, land, and water, that rely on current solar income and generate no toxic waste, that use safe, healthful materials that replenish the earth or can be perpetually recycled, and that yield benefits that enhance all life.

Over the past decade, the cradle-to-cradle framework has evolved steadily from theory to practice. In the world of industry it is creating a new conception of materials and material flows. Just as in the natural world, in which one organism’s “waste” cycles through an ecosystem to provide nourishment for other living things, cradle-to-cradle materials circulate in closed-loop cycles, providing nutrients for nature or industry. This model recognizes two metabolisms within which materials flow as healthy nutrients.

First, nature’s nutrient cycles constitute the biological metabolism. Materials designed to flow optimally in the biological metabolism are biological nutrients. Products conceived as these nutrients, such as biodegradable packaging, are designed to be used and safely returned to the environment to nourish living systems. Second, the technical metabolism, designed to mirror the earth’s cradle-to-cradle cycles, is a closed-loop system in which valuable, high-tech synthetics and mineral resources—technical nutrients—circulate in a perpetual cycle of production, recovery, and remanufacture. Ideally, all the human systems that make up the technical metabolism are powered by the renewable energy of the sun.

Biological and technical nutrients have already entered the marketplace. The upholstery fabric Climatex Lifecycle is a blend of pesticide-residue-free wool and organically grown ramie, dyed and processed entirely with nontoxic chemicals. All of its product and process inputs were defined and selected for their human and ecological safety within the biological metabolism. The result: the fabric trimmings are made into felt and used by garden clubs as mulch for growing fruits and vegetables, returning the textile’s biological nutrients to the soil.

Honeywell, meanwhile, is marketing a textile for the technical metabolism, a high-quality carpet yarn called Zeftron Savant, which is made of perpetually recyclable nylon 6 fiber. Zeftron Savant is designed to be reclaimed and repolymerized—taken back to its constituent resins—to become new material for new carpets. In fact, Honeywell can retrieve old, conventional nylon 6 and transform it into Zeftron Savant, which is in effect “upcycling” rather than downcycling an industrial material. The nylon is rematerialized, not dematerialized—a true cradle-to-cradle product.

In the commercial carpet industry, material recovery systems are providing a model for the development of technical metabolisms. Shaw Industries, for example, has developed a technical nutrient carpet tile for its commercial customers. The company guarantees that all of its nylon 6 carpet fiber will be taken back and returned to nylon 6 carpet fiber, and its safe polyolefin backing returned to safe polyolefin backing. Raw material to raw material. A cradle-to-cradle cycle.

Shaw’s technical nutrient carpet tile is conceived to be a product of service, a key element of the cradle-to-cradle strategy. Products of service are durable goods, such as carpets and washing machines, designed by their manufacturer to be taken back and used again. The product provides a service to the customer while the manufacturer maintains ownership of the product’s material assets. At the end of a defined period of use, the manufacturer takes back the product and reuses its materials in another high-quality product. Widely practiced, the product-of-service concept can change the nature of consumption as human systems powered by renewable energy reuse valuable materials through many product lifecycles.

On a large scale, cradle-to-cradle thinking can transform the nature of economies. In Chicago, for example, these principles are serving as a reference point as Mayor Richard Daley strives to make the city the greenest in America, a hub of energy effectiveness and beneficial material flows.

In a cradle-to-cradle economy, cities are the principal home and source of technical nutrition—the place where metals are forged, polymers synthesized, and tractors, computers, and windmills designed and manufactured. Cities send these materials forth into the world and receive them back as they move through closed-loop cycles. The countryside, meanwhile, can be seen as the home of the biological metabolism. Materials generated there—food, wood, fibers—are created through interactions of solar energy, soil, and water and are the source of biological nutrition for rural communities and nearby cities. One of the city’s fundamental roles in this metabolism is to return biological nutrition in a safe, healthy form, say as clean fertilizer, back to the rural soil. These flows of nutrients and energy are the twin metabolisms of the living city, the engines of the vibrant economies of the future.

Even nations as vast and influential as China have adopted cradle-to-cradle strategies. Building on a 4,000-year-old tradition of sustainable agriculture, Vice Minister of Science and Technology Madame Deng Nan announced in September 2002 that China will begin to develop industries and products based on cradle-to-cradle principles. Working with the China–U.S. Center for Sustainable Development, China is already developing a cradle-to-cradle village as well as solar and wind power enterprises.

The cradle-to-cradle strategy allows us to see our designs as delightful expressions of creativity, as life-support systems in harmony with energy flows, human souls, and other living things. When that becomes the hallmark of productive economies, consumption itself will have been transformed.

This essay originally appeared in Worldwatch Institute's State of the World 2004.