African food system and biodiversity mainly affected by urbanization via dietary shifts

Abstract

The rapid urbanization in Africa profoundly affects local food and ecological systems. According to earlier research, urbanization may cause food production and biodiversity losses as agricultural or natural lands are absorbed by expanding cities. Land-use displacement effects may buffer agricultural production losses or may lead to additional biodiversity losses but are often overlooked. Moreover, impacts of dietary changes associated with urbanization are rarely considered. To address this, we combined spatially explicit projections of African urban area expansion with observed rice consumption shifts to inform a partial equilibrium model (the Global Biosphere Management Model). We demonstrate the importance of displacement effects to identify potential food production or biodiversity issues until 2050 and argue for their integration in land-use planning and policymaking across spatial scales. We identify that because of agricultural displacement, the impact of urban area expansion on food production losses is probably limited (<1%)—at the cost of additional losses of natural lands by 2050 (up to 2 Mt). We also show that considering dietary shifts associated with urbanization increases rice consumption, production (+8.0%), trade (up to +2 Mt of required import) and agricultural methane emissions (up to +12 MtCO2-equivalent yr–1), thereby underscoring the need for a systems approach in future sustainability studies.