Improved water management can increase food self-sufficiency in urban foodsheds of Sub-Saharan Africa

Rising urban food demand in Sub-Saharan Africa will put pressure on local resource boundaries, such as the available land area and water resources. In assessing the extent to which urban centres can source from nearby areas in future, earlier analysis has concentrated on agronomic measures, aiming at yield gap closure. Here, we address the potential of local water conservation measures to help achieve food self-sufficiency in Sub-Saharan Africa by 2061–2070, along the concept of urban ‘foodsheds’, matching crop-based food supply and demand in the surroundings of large cities for all major food groups. We find that ambitious but plausible levels of water conservation, primarily raising productivity on rainfed lands, have the potential to increase overall food production by 12% and food self-sufficiency levels in all major foodsheds to over 75%, with the region as a whole becoming self-sufficient. The increase in production could limit the projected required expansion of agricultural land use by more than 25%, which has important implications for biodiversity, land use-related conflicts and carbon sequestration.