The development of scenarios is based on the identification and articulation of some underlying factors – the driving forces. Driving forces are elements that cause change to occur and their unfolding and interaction is responsible for the trends envisaged in each scenario. Some driving forces are not directly controllable and these have to be addressed in the scenario. Controlled forces are those that can be shaped and these form the basis for the recommendations and means of implementation prescribed in the scenarios. Driving forces are sufficiently strong to direct the course of growth of the society and change in environment. They set the initial course for development, and their impacts are potent enough to change the course of development. Therefore, they define departure points for the environmental issues that they influence. Their effects can be short and sharp, or long-lasting. Furthermore, driving forces operate at different scales of intensity and magnitude, reverse direction, appear or disappear as the case may be. The major driving forces defined for the AEO-2 are demographics, health, economics, social issues, culture, technology, governance, peace and conflict. (An overview of these is given in Chapter 1: The Human Dimension and the relationships between them is further developed in Chapter 8: Interlinkages: The Environment and Policy Web.) To these drivers we may add climate change and natural disasters. Depending on the environmental or development issues, some of the driving forces may take the form of pressures and/or responses. This section highlights how each of these may influence environment and development in Africa, and establishes their significance for the scenarios. The specific influence of the driving forces on selected issues is discussed subsequently under the four themes identified for AEO- 2 scenario analysis (land, freshwater, atmosphere, and coastal and marine environments). The overall trends and implications of these drivers for the state of the environment are considered in Section 2: Environment State-and-Trends: 20-Year Retrospective. As the driving forces have not changed since the AEO-1 report this discussion draws extensively on that report.