Environmental sustainability: Universal and non-negotiable

After deploring the mystification of the term ''sustainability'' and tendencies to conflate it with society's desiderata, we desegregate three types of sustainability: social, economic, and environmental. After clarifying these three linked and overlapping concepts, and construing them with ''sustainable development,'' we distinguish quantitative throughput growth from qualitative development, and mention intergenerational equity and scarcity of natural capital that together lead to the definition of ''environmental sustainability'' by the output/input rule, i.e., keep wastes within assimilative capacities; harvest within regenerative capacities of renewable resources; deplete non-renewables at the rate at which renewable substitutes are developed. After distinguishing development from sustainability and from growth, the paper describes the concept of natural capital and uses the concept to present four alternative definitions of environmental sustainability. Next, the paper presents criteria for analyzing environmental sustainability and uses the Ehrlich-Holdren framework in which ''Population,'' ''Affluence,'' and ''Technology'' are examined separately. The paper then nuances the I = PAT identity and starts to disaggregate the components of sustainability into more dynamic formulations. The final section describes how one large development agency, the World Bank, is endeavoring to incorporate these new principles into its operations.