Projected climate change impacts on mean and year-to-year variability of yield of key smallholder crops in Sub-Saharan Africa

This study investigates the impacts of climate change in Sub-Saharan Africa on yields of maize and cereals (sorghum and millet) which are of particular importance to smallholding farmers. An ensemble of six climate scenarios are input to a crop model to compute changes in food availability (mean annual yield) and food stability (standard deviation and coefficient of variation) between the periods 1971-2000 and 2041-2070. Our results show a particular risk to food security in Central Africa where mean maize yield decreases over 89% of harvested maize areas, and its variability increases over 54% of these areas. A decline in mean maize yield is computed over 85% of harvested maize areas in West Africa, 29% in Southern Africa and 32% in East Africa. Within the limits of the analysis, we find that mean yields of tropical cereals will be more robust to climate change than maize, although yields still decrease over 23% of tropical cereal harvested areas. We find declining food stability over 37% of harvested maize areas and 46% of harvested tropical cereal areas. Our findings also indicate that a range of options including regional markets, strategic food reserves, and new cultivars could help farmers adapt to these changes.