low at less than 7 kg per year, but population expansion and global price increase will sustain growth in capture and aquaculture fisheries. Although capture fisheries will continue to provide the bulk of fish for food in SSA for many decades, multiple pressures will gradually shift the focus to aquaculture, projected to play an increasing role in food security with a 6% rate of expansion by 2020. Local and regional fish trade in SSA will expand through regional cooperation and appropriate national policies, value adding and better market chains. The management of bio-invasion in SSA will have to overcome current challenges of inadequate public–private partnership engagement, apply traditional and local technical knowledge systems, and increase awareness to the environmental, social and economic costs of producing any given species.

5. The agroecosystems of SSA are diverse and have varying potential for sustainable development goals through benefits from agrobiodiversity, agroecotourism and commoditization of services like carbon sequestration. As the numerous benefits and multiple functions of agroecosystems to society become recognized and compensated, such as environmental services, continuity of social and cultural heritage, etc., agriculture in SSA is projected to become more integrated. Agroecotourism will propel economic development only if it is socially accepted in SSA, which depends on opportunities for local communities. The carbon trade and carbon sequestration services provided by agro-ecosystems are already picking up in SSA and are expected to be instrumental to poverty reduction strategies in the region. As the long-term value of agroecosystems are recognized and valued, new institutional mechanisms will be developed to realize effective markets for environmental goods and services.

6. A sub-Saharan Africa with less poverty, greater food security, and a healthier environment is possible, but will not come about without explicit policy steps in that direction. The costs of not making the necessary investments in sub-Saharan Africa will be tremendous, not only to the region but to the rest of the world. Reversing the tide in sub-Saharan Africa enough to allow for an overall economic sustainability would require an increase in total investments on roads, irrigation, clean water, education, and agricultural research. Crop yields would have to grow at a minimum threshold in order to achieve this. Even more significantly, total gross domestic product (GDP) would have to grow at an annual rate of 8 to 10%.

4.1 The Evolution of SSA Food Systems towards 2050
Projections in this chapter build on past and current trends in SSA food systems and existing projections of agricultural products and services to present an assessment of future agricultural and AKST developments. Both a realistic (evolution of current situation with no major changes) and a pessimistic approach to an assessment of future food systems alternatives would lead to system deficits and greater inefficiencies than reported in literature. Conversely, an optimistic approach equates projected production to projected demands. This presents the assessment with the opportunity