Brown, Becky J., Mark E. Hanson, Diana M. Liverman, and Robert W. Merideth, Jr. 1987. "Global Sustainability: Toward Definition." Environmental Management 11 (6): 713-719.

Thesis:

"...we examine the concept of sustainability, review some of the ways in which it has been defined, and attempt to clarify the use of the terms sustainable, sustained, and sustainability in the global context" (p. 713).

Summary:

Various uses and conceptualizations of sustainability:

1. Sustainable Biological Resource Use: Foresters and fisheries biologists use the concept of maximum sustainable yield in making harvest decisions. However, maximum forestry yields are difficult to estimate because of the variability of natural regeneration rates due to climate, soils and disease. Likewise, fish harvests are difficult to estimate because of problems in assessing current ocean stocks.

2. In sustainable agriculture, trade-offs exist between land conservation and economic and social viability.

3. Carrying capacity has been used extensively in describing sustainability; however, it can only be applied to humans by analogy. Studies are often flawed because human groups exchange goods and services between countries as well as between urban-industrial and rural regions. Carrying capacity tends to be discussed as it relates to resource use (food and fuelwood) and population growth.

4. Use of renewable energy appears with discussions about society's transition from nonrenewable energy sources to renewables. Unsustainable energy use is that which depletes stocks faster than they can renew. Currently, focus is on the transition from unsustainable energy use to sustainable energy use, specifically, whether the transition will be smooth or occur amidst serious economic disruption.

5. Sustainable Society and Sustainable Economy: Mainstream economists tend to dismiss steady-state conceptualizations of sustainability. The authors note, "a distinct split exists between economists who view continued growth as an essential element of a sustainable economy and those who view a steady-state economy...as essential" (p. 716).

6. Sustainable development is associated with ecodevelopment and defined by Dasmann (1985) as "...development...within the constrains of local ecosystems" (p. 716).

Emerging from this review, the authors identify three perspectives or contexts of sustainability: social, ecological and economic. Socially defined sustainability is the "survival and happiness of the maximum number of people, or the provision of minimum needs to even the poorest groups" (p. 716). The ecological definition focuses on "natural biological processes and the continued productivity and functioning of ecosystems" (p. 716). Finally, economic sustainability includes both the inevitability of economic growth without consideration of sustainability except as a recognition of ecological limits which are placed on economic growth.

The authors present six "essential elements in defining sustainability:" 1) The continued support of human life on earth; 2) Long-term maintenance of the stock of biological resources and the productivity of agricultural systems; 3) Stable human populations; 4) Limited growth economies; 5) An emphasis on small-scale and self-reliance; 6) Continued quality in the environment and ecosystems.

The authors' definition of a sustainable world is: "one in which humans can survive without jeopardizing the continued survival of future generations of humans in a healthy environment" (p. 717). The authors argue that basic human support systems are directly linked to the sustained functioning of natural ecosystems: "It is important to recognize that widespread provision of even basic survival needs will become increasingly unsustainable if population growth is not controlled" (p. 717). Further, sustainability also implies the existence and operation of an infrastructure, services and government that will encourage and support the sustainable use of the biosphere and equitable resource use" (p. 718).

In conclusion, definitions of sustainability and sustainable development vary across contexts and scales. Depending on the definition, it can either develop into a realistic goal or remain an utopian ideal. Different societies have different cultural expectations of sustainable development further complicating the process. Finally, setting the priorities of sustainability is value-laden and so requires a clear definition from the outset.

Keywords: global sustainability, ecologically sustainable development, sustainable use of the biosphere, intergenerational equity