"Sustainable development"the reconciliation of society's developmental goals with its environmental limits over the long termis the most recent conceptual focus linking the collective aspirations of the world's peoples for peace, freedom, improved living conditions, and a healthy environment. These four conditions frequently emerge as key ideals of the last half of the 20th century. Peace, the first, was thought to be secured in the postwar world of 1945. It was thereafter complicated by the nuclear arms race, then maintained globally but still fought locally in the long cold war, and is now sought again in places as diverse as Bosnia, Central Africa, the Middle East, and Ireland. Freedom proclaimed itself in the struggle to end imperialism, to extend human rights, and to end totalitarian oppression. Now, in the wake of establishing widespread national independence, development is the primary ideal that captures the hopes of the poorest two-thirds of the world, who aspire to both the basic necessities and the material well-being of the wealthy third. The most recently emphasized ideal has concerned the earth itself, initially focusing on natural resources, later extending to the human environment, and finally to the complex systems that support life on earth. Characteristic of the last quarter of a century is the effort to link all these aspirations of humankindparticularly through the realization of how often the pursuit of one condition requires pursuit of the others. International high-level commissions (such as the Independent Commission on International Development Issues 1980 [Brandt], the Independent Commission on Disarmament and Security Issues 1982 [Palme], and the World Commission on Environment and Development 1987 [Brundtland]), often followed by great international conferences, have attempted to make a case, moral and pragmatic, for such links. A specific recent focus has thus been on the critical relationships between development and the environment.
Many notions now incorporated within the concept of sustainable development can be traced back through the 1980 World Conservation Strategy and the 1972 Stockholm Conference on the Human Environment to the early days of the international conservation movement.1 Today's understanding of the links between environment and development, however, is little more than a decade old, stemming from the Brundtland report, Our Common Future.2 The idea of sustainable development was given additional impetus at the 1992 United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro. It has rapidly spread and is now a central theme in the missions of countless international organizations, national institutions, "sustainable cities," and locales.
The genius of the idea of sustainable development lies in its attempt