The goals of sustainable development are summarized in Our Common Future, or the Brundtland Commission, which states that we must meet 'the needs of the present gen-eration without compromising the ability of future generations to meet their own needs'. These needs could be economic, political, socio-cultural and ecological. Thus, the management of the environment has always presented people with many problems and challenges, largely because of its complex nature, and of the com-plex interactions and relation-ships within it. Furthermore, since environmental management valueladen, there is usually more than one way of conceptualizing and expressing the value of the environment and its resources. The result is that environmental management normally requires that we deal with several elements of the envi-ronment, and with several perspectives reflecting the different concepts and perceptions held by dif-ferent societies, belief systems and interests.
We have constructed scenarios from: our understanding of current conditions and driving forces; a vision of the future; and a coherent story of a process of change, leading to that future. We have used both imagination and science as ingredients for generating effective scenarios, and we have made quantitative assumptions across a range of dimensions: eco-nomic growth and struc-ture, popula-tion, technology, resources and the environment. We have used the scenarios to take the inherent uncertainty in future development as the point of departure, and to seek to formulate plausible stories about alternative possibilities that can emerge from current conditions and driving forces.
As a first step in scenario development, we need to be able to calibrate relationships between the more discerning vari-ables or driving forces with what occurs in real-life situations. While data currently preclude a full investigation along these lines, they are undoubtedly necessary for the future development of scenarios. However, for studies which link vulnerability to scenario development, we need to be able to define the stress variables, such as people under stress for water or people living within a certain distance of a potentially dangerous hazard.
Nevertheless, there seems to be no time more opportune than now to discuss issues that affect the sustainability of the African environment. The reasons are many, but perhaps most important is that there is a unity of purpose in the minds of African leaders on the urgent need to eradicate poverty from the region and to give development a much-needed direction. For instance, NEPAD seeks 'to build on and celebrate the achievements of the past, as well as reflect on the lessons learned through painful experience, so as to establish a partnership that is both credible and capable of implementation. Africa must not be the wards of benevolent guardians; rather they must be the architects of their own sustained upliftment' (authors' emphasis). Furthermore, NEPAD centres around African ownership and management, issues that were considered germane to development of a Great Transitions scenario.