Water resources transfers through southern African food trade: water efficiency and climate signals

Abstract:

Temporal and spatial variability of precipitation in Southern Africa is particularly high. The associated drought and flood risks, combined with a largely rainfed agriculture, pose a challenge for water and food security in this region. It is thus important to understand both how climate variability affects agricultural productivity and how intra- and extra-regional trade can contribute to the region's capacity to deal with climate-related shocks. We combine international food trade data and a global hydrological model to quantify the water resources embedded in international food trade in southern Africa and with the rest of the world, from 1986-2011. We analyze the impacts of socio-economic, political and climatic changes on agricultural trade and embedded water resources during that period. We find that regional food trade is efficient in terms of water resources but may be unsustainable because water-productive exporters, like South Africa, rely on increasingly scarce water resources. The role of imports from the rest of the world in the region's food supply is important, in particular during severe droughts. This reflects how trade can efficiently redistribute water resources across continents in response to a sudden gap in food production and water productivity. As regional collaboration strengthens through the Southern Africa Development Community (SADC) and trade with other regions increases, our results point out opportunities for improved water-efficiency and sustainability of the region's food production via trade.