Abstract
We have reached a unique juncture in human ecological history, one requiring a radical reconfiguration of planning values and goals. The "ecological footprint" of the global economy is already larger than the planet, yet a quarter of humanity still lives in poverty, the human family is expanding by 90 million a year, and material demands everywhere are rising. An unlikely tenfold reduction in the energy and material intensity of economic activity would be required to accommodate anticipated economic growth safely, posing an enormous challenge to planners in facilitating the transition to sustainability. Failure enhances the considerable possibility of global disaster.