The concept of “sustainable development” has a long history in scientific thought. As early as 1749 the Swedish botanist Linnaeus in his Oeconomia naturae, linked economy to nature in a way that resembles many of the concepts of sustainable development. His economic program focused on the need to make efficient use of existing resources rather than pursue military expeditions as a means of economic survival. Over 200 years later, in Our Common Future, the World Commission on Environment and Development (WCED, 1987) gave international prominence to sustainable development and defined it as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Our Common Journey, a report of the U.S. National Research Council (NRC, 1999), added a temporal dimension, defining sustainable development as “the reconciliation of society’s developmental goals with its environmental limits over the long term.” These definitions reflect the growing need to provide an ethical framework for integrating developmental and environmental goals. Sustainable development is therefore a set of guiding principles whose implementation is reflected in a variety of action programs, of which Agenda 21 is the most prominent.