2.   Harwood (1990) : Sustainable agriculture is a system that can evolve indefinitely toward greater human utility, greater efficiency of resource use and a balance with the environment which is which is favourable to humans and most other species. 3. Pearce, Makandia & Barbier (1989) Sustainable development involves devising a social and economic system, which ensures that these goals are sustained, i.e. that real incomes rise, that educational standards increase, that the health of the nation improves, that the general quality of life is advanced. 4.   Conway & Barbier (1990) from 1,2 & 3: We thus define agricultural sustainability as  the ability to maintain productivity, whether as a field  or farm or nation. Where productivity is the output of valued product per unit of resource input. 5.   Daly (1991) then argued that: Lack of a precise definition of the term 'sustainable development' is not all bad. It has allowed a considerable consensus to evolve in support of the idea that it is both morally and economically wrong to treat the world as a business in liquidation. Pause for thought....... The world, a business in liquidation, would you consider this a sensible way for international powers to approach the concept of sustainability (at any level), what are the reasons for your answer? 6.   Heinen (1994) No single approach to 'sustainable development' or framework is consistently useful, given the variety of scales inherent in different conservation programmes and different types of societies and institutional structures 7.   IUCN, UNEP, WWF (1991): Sustainable development,