The 20th century industrial model follows a linear course -- what many people now call "cradle to grave" -- meaning that products we manufacture die when they're no longer useful to their owner, sent to a point of no return in a landfill somewhere. It's a model that epitomizes a wasteful and unsustainable system. In a sustainable industrial world, we take that fatal end point and reconnect it to the beginning, closing the loop and creating the possibility of reusing those dying industrial ingredients to manufacture a new generation of useful items. Instead of a linear "cradle to grave" model, we now have a cyclical "cradle to cradle" model.
In their book, Cradle to Cradle, William McDonough and Michael Braungart illustrate the potential of closed loop manufacturing to bring about a new industrial revolution, free of waste and pollution, which promises a sustainable material civilization. It's an idea that's been widely adopted by sustainable designers and architects, developed into certification criteria for sustainable products, and used as a clear and basic teaching tool for comparing the practices we need to leave behind with the ones that can carry us well into the future.
William McDonough's Cradle to Cradle speech at TEDTalks '06 is available here.
For a thorough explanation of the cradle to cradle idea, check out this podcast with William McDonough on Social Innovation Conversations:
Also, their is a TED talk on Cradle to Cradle. Just go to TED.com and search "cradle to cradle". Very interesting and fantastic lateral thinking!
Cradle to cradle is also the way nature works and the basis for most human activity since we first walked upright. The linear phase in history is a glitch but a serious one that can be corrected only by a deep reform of capitalism. The basic problem is that there is no charge from nature for waste. This can be corrected with a new form of economic instrument based on a simple variation of insurance, to prevent problems rather than pay for them afterwards. I'm happy to send my peer-reviewed paper on this. See www.blindspot.org.uk. Or May 2007 issue of Journal of Cleaner Production.