The most popular definition can be traced to a 1987 UN conference. It defined sustainable developments as those that "meet present needs without compromising the ability of future generations to meet their needs"(WECD, 1987). Robert Gillman, editor of the In Context magazine, extends this goal oriented definition by stating "sustainability refers to a very old and simple concept...(The Golden Rule)...Do onto future generations as you would have them do onto you."
These well-established definitions set an ideal premise, but do not clarify specific human and environmental parameters for modeling and measuring sustainable developments. The following definitions are more specific:
B. "Sustainability identifies a concept and attitude in development that looks at a site's natural land, water, and energy resources as integral aspects of the development" (Vieira,1993).
C. "Sustainability integrates natural systems with human patterns and celebrates continuity, uniqueness and placemaking" (Early, 1993).