21
incoming shortwave radiation), many places are likely to have less available water
both in streams and in the soil, because warmer temperatures will cause more water
to evaporate directly from the soil or to be transpired through plants (Girvetz and
Zganjar 2014).
Changes to temperature and precipitation have immediate implications for food
production and security across the continent (Niang et al. 2014; Porter et al. 2014;
Muller et al. 2011; Rosenzweig et al. 2014). Current growing areas of maize and
beans are projected to experience yield reductions of 12–40% by the 2050s. The
climate suitability of most major crops is also projected to shift as climate warms
(Rippke et al. 2016; Zabel et al. 2014). Ramirez-Villegas and Thornton (2015) have
shown that two of Africa’s staple crops—maize and beans—are projected to have
severe decreases in suitability across much of the continent (Fig. 2.5). Increasing
atmospheric levels of carbon dioxide is likely to affect the nutrient content of plants,
resulting in serious protein and micro-nutrient cold spots in parts of sub-Saharan
Africa (Medek et al. 2017; Myers et al. 2014, 2015a, b). This poses a serious
Fig. 2.5 Projected median changes in climatically suitable area and productivity by 2050s and
RCP8.5, relative to a historical period (1970–2000). Median values given are based on ensemble
simulations of niche and productivity models, and therefore should be interpreted in light of associated uncertainties. Livestock productivity refers to annual net primary productivity (ANPP) of
rangelands (a proxy for livestock productivity), rather than to a direct measure of meat or milk
productivity. (Source: Dinesh et al. 2015)
2 Future Climate Projections in Africa: Where Are We Headed?
incoming shortwave radiation), many places are likely to have less available water
both in streams and in the soil, because warmer temperatures will cause more water
to evaporate directly from the soil or to be transpired through plants (Girvetz and
Zganjar 2014).
Changes to temperature and precipitation have immediate implications for food
production and security across the continent (Niang et al. 2014; Porter et al. 2014;
Muller et al. 2011; Rosenzweig et al. 2014). Current growing areas of maize and
beans are projected to experience yield reductions of 12–40% by the 2050s. The
climate suitability of most major crops is also projected to shift as climate warms
(Rippke et al. 2016; Zabel et al. 2014). Ramirez-Villegas and Thornton (2015) have
shown that two of Africa’s staple crops—maize and beans—are projected to have
severe decreases in suitability across much of the continent (Fig. 2.5). Increasing
atmospheric levels of carbon dioxide is likely to affect the nutrient content of plants,
resulting in serious protein and micro-nutrient cold spots in parts of sub-Saharan
Africa (Medek et al. 2017; Myers et al. 2014, 2015a, b). This poses a serious
Fig. 2.5 Projected median changes in climatically suitable area and productivity by 2050s and
RCP8.5, relative to a historical period (1970–2000). Median values given are based on ensemble
simulations of niche and productivity models, and therefore should be interpreted in light of associated uncertainties. Livestock productivity refers to annual net primary productivity (ANPP) of
rangelands (a proxy for livestock productivity), rather than to a direct measure of meat or milk
productivity. (Source: Dinesh et al. 2015)
2 Future Climate Projections in Africa: Where Are We Headed?