The cultural norms or core values for sustainable development are an amalgamation of core social values and core environmental values. Widely-shared core social values became strikingly articulated following the Second World War via such instruments as the 1948 Genocide Convention and the 1948 Human Rights Declaration. By contrast, widely-shared core environmental values did not surface until some two decades after the Second World War, being first clearly expressed in the 1972 Stockholm Declaration, to be followed by the 1982 World Charter for Nature and, more recently, by the 1992 Rio Declaration. I find that whereas the emerging core social values have until quite recently been essentially innocent of environmental concerns, the emerging core environmental values have been from the start generally couched in social terms.

Key ethical issues regarding the cultural norms underlying sustainable development include the questions of how to strike a proper balance between anthropocentric and ecocen-tric justifications; and a proper apportionment of the global biosphere between humankind and the other life on earth. Several lines of evidence suggest to me that the environmental and social strands of widely-shared core values for sustainable development are beginning to merge, and that there has begun to occur a slow but progressive development in mainstream thinking toward a recognition of an unbreakable link between social development and environmental conservation.

A number of major stumbling blocks to the achievement of sustainable development exist of course, amongst them the imbalance between human numbers plus needs and available natural resources, the prevalence of totalitarian and corrupt regimes, and the ineffective system of peaceful world governance. Despite obstacles to sustainable development, a trend towards a commitment to it seems evident in such components of society as governments, intergovernmental agencies, non-governmental organizations, academia, religious bodies, and grass-roots movements.