rural livelihoods; and facilitating social and environmental sustainability?
     To analyze this question based on currently available knowledge, the key issue was deconstructed into a series of more specific questions:
•   What will be the future of food systems, agricultural products and services?
•   What are the major uncertainties of the drivers and pro­jections?
•   What are the implications for AKST in the future?
•   What will be the implications for development goals?

4.1.1      Approaches of scenarios development and impact assessment
The specific questions identified above can be addressed by either developing plausible futures based on socioeconomic, technological and political assumptions, or by extrapolat­ing agricultural or related variables, based on assumptions made about the baseline period. Each driver might take different shapes in the future based on these assumptions. Recently many studies developed scenarios to help deci­sion makers see different plausible futures with reference to climate change, ecosystems, environment and agriculture. These scenarios considered various timelines for the projec­tions (Table 4-1).

     Conventional impact assessment of agricultural science and technology (S&T) has been conducted mainly by social scientists, especially economists, in national and interna­tional agricultural research organizations or policy making agencies. The explicit purpose of such assessments is to un­derstand how S&T as a major driver of agricultural growth (productivity and production) brings returns and thereby legitimizes investments made already as well as the scope for further investments in S&T. Global assessments such as the Millennium Ecosystem Assessment (MA) and the Inter­governmental Panel on Climate Change (IPCC) (Table 4-1) have been conducted to enable a better understanding of drivers and processes of change in the ecosystem and global climate regimes in order to identify options for action to address the drivers of change and/or the processes. These assessments have been conducted by large groups of people with a variety of expertise and experience, drawing upon a variety of natural science and social science disciplines as well as regional/local experiences.

4.1.2     Assessment approach for ESAP
This chapter presents an assessment of agricultural change and its drivers from the existing literature (national and in­ternational) based on historical trends and future projec­tions of key drivers of change and expected changes in future policies and politics (See Global Chapter 5). The assessment