At the end of the last Millennium, when lofty visions were as ubiquitous as talk of what mankind has accomplished and in what direction it is heading, 'sustainable development' or 'sustainability' became the theoretical basis and an increasingly important societal norm for human development worldwide (Keiner, 2006, p.1).

Since it was introduced into the global discourse in the 1980s, sustainable development has become an important " buzzword" in development circles and beyond. Already in the 1970s it was perceived that the classical concept of development, one that focused almost exclusively on economic growth, would eventually cause a total collapse of many, if not all, natural systems (SOGESID, n.d.). Phenomena such as acid rain, global warming, and holes in ozone layer provided scientific evidence of the global impact of humans on their environment.

The call for a new paradigm of development originated from this growing awareness that the environment was being transformed on a global and historically unprecedented scale, as well as socio-economic issues related to the poverty, and worry about a healthy future for mankind (Wironen, 2007). The need to address these issues came into direct conflict with the neoliberal dominance of economic discourse in the 1980s (e.g., the policies of Reagan in the U.S. and Thatcher in the UK). In the neoliberal view economic production was the main priority. Economic growth "was then seen as the key to humanity's well-being and, through growth, poverty would be overcome: as everyone floated higher those at the bottom would be raised out of poverty" (Hopwood, Mellor, & O'Brien, 2005). Criticisms of this approach became widespread as the evidence grew that economic growth did not automatically improve people's lives, either within nations or internationally. The existing notions of "progress," "growth," and "development" were challenged. (Du Pisani, 2006). In contrast to the dominant outlook of the last couple of hundred years, particularly those emanating from the developed "North" that tend to separate the environment from socio-economic issues, a new paradigm linking environmental concerns to economic development was sought (Hopwood et al.).

Gradually a consensus emerged that there was a need for a new, more system-oriented paradigm that would take cognizance of

• The emerging new world order after the collapse of communism as well as the economic failures of unbridled capitalism
• The seemingly inevitable cycle of poverty, human suffering, and environmental destruction in many developing countries
• The existence and inter-relationship between economic and ecological problems
• The need for global mechanisms to promote protection of democratic principles and human rights (Estes, 1993)

In sum, in opposition to a development model based almost solely on economic growth, and concurrent with a growing awareness of environmental issues on a global scale, it was thought that a new development model was needed, one that would take into account both economic growth and use of natural resources. It was in this context of opposition to the traditional economic growth model, a new paradigm focused on the concept of sustainable development emerged. Sustainable development arose as an alternative to contemporary development theory that offered a way forward for both environmentalists fearful of a global ecological crisis, as well as those in the development community searching for an alternative to the neo-liberal paradigm within development (Wironen, 2007).

The central concept in this new model of sustainable development was sustainability. In the past, it was argued, the sustainability of human society was not really at stake and was taken for granted. Historically the slow and sometimes glacial pace of environmental change seemed to leave plenty of time for adaptation to and/or evasion of any potential threat to the survival of human society. The only alternative to sustainability, unsustainability, did not imply any immediate existential threat. However, as the rate of change in a system begins to approach a rate of speed that threatens the ability to respond, a system can lose both its viability and sustainability (Bossel, 1999).

If we view sustainability in terms of seeking a balance between use of natural resources and the impact of this on the environment, it has clearly been an issue throughout human history. In the modern era the emergence of the term sustainability seems to be more specifically rooted in notions of biological and ecological conservation, and may have been first used in forestry in the context of maintaining a balance between harvesting old trees and insuring a sufficient supply of new trees to replace them (Du Pisani, 2006; Keiner, 2005). According to Voinov and Smith (1994), despite considerable literature appearing in both the scientific and public press, no common definition of sustainability has emerged. As a result people define sustainability in ways that suit their particular application of it. They argue that part of what makes defining sustainability controversial is that it actually brings ecological problems from the realm of science into people's every day lives. When translated into the world of concrete personal and commercial interests in scientific discourse a scientific abstract concept becomes a term that is easier to understand, than to explain. Voinov and Smith conclude that attempts to find an exhaustive definition of sustainability are rather futile. Instead they propose describing sustainability in terms of three conditions that are necessary for system to achieve sustainability:

1. the system does not cause harm to other systems, both in space and time;

2. the system maintains living standards at a level that does not cause physical discomfort or social discontent to the human component;

3. within the system life-support ecological components are maintained at levels of current conditions, or better.