Sustainability Economics: Synthesis and DefinitionBringing the normative foundations of“sustainability”and“eco-nomics”(in its modern interpretation) together, one might say thatsustainability economics is ethically founded in the idea ofefficiency, that is non-wastefulness, in the use of scarce resourcesfor achieving the two normative goals of (1) the satisfaction of theneeds and wants of individual humansand(2) justice, includingjustice between humans of present and future generations andjustice towards nature, in the setting of human–nature relation-ships over the long-term and inherently uncertain future.Considerations of efficiency in the allocation of scarce resourcesthenrefertothreebasicalternatives: (a)scarceresourcesmaybeusedin alternative ways to achieve one of the normative goals ofsustainability economics, say intergenerational justice properlyspecified; (b) scarce resources may be used to achieve alternativenormative goals of sustainability economics, say intra- and intergen-erationaljustice;and(c)scarceresourcesmayb