The Difficulty in Defining Sustainability

Beyond ambiguity of meaning there also is disagreement about the prospects for achieving sustainability. The Brundtland Report foresees “the possibility for a new era of economic growth, one that must be based on policies that sustain and expand the environmental resource base.” Some scholars, notably the economist Julian Simon, question whether sustainability is a significant issue, pointing out that humankind consistently has managed in the past to avoid the specter of Malthusian scarcity through resource substitution and technical ingenuity. Others, notably the ecologists Paul and Anne Ehrlich and the economist Herman Daly, believe that the scale of human pressure on natural systems already is well past a sustainable level. They point out that the world’s human population likely will at least double before stabilizing, and that to achieve any semblance of a decent living standard for the majority of people the current level of world economic activity must grow, perhaps fivefold to tenfold. They cannot conceive of already stressed ecological systems tolerating the intense flows of materials use and waste discharge that presumably would be required to accomplish this growth.