Climate and southern Africa's water–energy–food nexus

Abstract

In southern Africa, the connections between climate and the water–energy–food nexus are strong. Physical and socioeconomic exposure to climate is high in many areas and in crucial economic sectors. Spatial interdependence is also high, driven, for example, by the regional extent of many climate anomalies and river basins and aquifers that span national boundaries. There is now strong evidence of the effects of individual climate anomalies, but associations between national rainfall and gross domestic product and crop production remain relatively weak. The majority of climate models project decreases in annual precipitation for southern Africa, typically by as much as 20% by the 2080s. Impact models suggest these changes would propagate into reduced water availability and crop yields. Recognition of spatial and sectoral interdependencies should inform policies, institutions and investments for enhancing water, energy and food security. Three key political and economic instruments could be strengthened for this purpose: the Southern African Development Community, the Southern African Power Pool and trade of agricultural products amounting to significant transfers of embedded water.

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Figure 1: Average annual total precipitation (1961–1990) and multimodel ensembles of projected changes in national average annual precipitation (as a fraction of 1961–1990 mean) and national average annual mean temperature (°C change from 1961–1990 mean).
Figure 2: Modified version of the nexus framework of Hoff11 integrating global drivers with fields of action, to illustrate the main timescales of climate as a driver in southern Africa.
Figure 3: National rainfall variability and socioeconomic exposure to hydroclimate.
Figure 4: Rainfall and sea surface temperature; Kendall's tau correlations.
Figure 5: Simulated climate change impacts on rainfed and irrigated maize yield in the top five producing countries of southern Africa for the near, medium and long time horizon under Representative Concentration Pathway 8.5.
Figure 6: Water resources transfers (km3) through food trade in 2007.

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Acknowledgements

This work was supported by the following Belmont Forum members: US National Science Foundation (grant number 1342742), UK Natural Environment Research Council (grant number NE/L008785/1) and the South Africa National Research Foundation (grant number 86975), according to each agency's policies. T.K. and K.L. are funded, through IRI THESys, by the German Excellence Initiative. IFPRI's contribution is under the CGIAR Research Program on Water, Land and Ecosystems.

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Correspondence to Declan Conway.

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Conway, D., van Garderen, E., Deryng, D. et al. Climate and southern Africa's water–energy–food nexus. Nature Clim Change 5, 837–846 (2015). https://doi.org/10.1038/nclimate2735

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