Modelling and forecasting roots & tubers losses and resulting water losses in sub-Saharan Africa considering climate variables

The implications of climate change coupled with anthropogenic activity on water resources have caused great concern, particularly in areas vulnerable to water stress such as sub-Saharan Africa. We focused on the future magnitude of food loss (FL) in African regions, using an ARIMAX model to fit and forecast roots & tubers (R&T) losses of five major crops cultivated in Africa regions, including cassava, potato, sweet potato, yam, and “other” roots & tubers. The forecast was done up to 2025 under the influence of five exogenous variables, namely, gross domestic product, harvested area, precipitation, temperature, and food production. In addition, the future crop water requirement (CWR) of production under climatic variables, and the associated water loss embodied in FL were quantified by means of CROPWAT 8.0. Our findings showed that in 2025 the magnitude of FL is expected to increase by 19.06%, 104.78%, and 27.72% at 2013 levels for East Africa, Middle, and West Africa, respectively. Under future climate the CWR of the selected crops is expected to be higher in West Africa (1790.24 m3/tonne), than in East (989.03 m3/tonne), and Middle Africa (903.64 m3/tonne). The future water loss embodied in FL is expected to be 114.37, 112.80, and 12.06 m3/cap/yr for the West, Middle, and East Africa regions, respectively. Our results show that measures aimed at preventing FL will also alleviate pressure on available water resources.