Water Worrying Future for Africa

 

Figure 1: Desiccation due to Climate Change in Africa

Source: United Nations

The image above of land in a state of extreme dryness helps to demonstrate the intensifying impacts of climate change in Africa. Africa is disproportionately affected with warming predicted to be 1.5 times the global average (Christensen et al., 2007). Population growth of 1.6-3.1% per annum is the highest in the world, predicted to increase by over half a billion by 2050 (UN, 2007). Thus, it is inevitable demand for freshwater will increase, especially in the agricultural sector to boost food production (Taylor et al., 2009). 

 

Across Africa, climate is already a fundamental driver of food security since a large proportion of Africa’s crop cultivation directly depends on rainfall (Challinor et al., 2007; Gregory et al., 2005). This is the case in sub-Saharan Africa with 89% of cereals rainfed (Cooper, 2004). Thus, agricultural systems are already vulnerable, but a doubling of CO₂ could make the situation worse. 

 

This post will draw your attention to the worsening future Africa is set for – firstly addressing the effect of increasing on groundwater through variability in rainfall and temperatures and then addressing the impact of this on food security due to the escalating imbalance of freshwater supplies (Carter and Parker, 2009). 

 

Impact of climate change on rainfall on groundwater

 

A previous blog discussed the potential of groundwater in Africa with an estimated total storage of 0.66 million km³. The gradual movement of groundwater into aquifers below means water quality is much better than that of surface waters and is more resilient to variations in climatic conditions (Taylor et al., 2009). Nonetheless, storage of groundwater is still sensitive to hydrological change. 

 

Rainfall 

The effects of climate change on water availability are difficult to conclude. Firstly, it is thought that rainfall intensities are projected to increase leading to greater variability in river discharge thus, soil moisture. Similarly, in sub-Saharan Africa, high intensity rainfall will contribute to soil degradation, erosion and desertification creating problems vis-à-vis the viability of land for crop cultivation due to nutrient depletion in the soil (Thompson et al., 2010). More intense rainfall will increase the risk of flooding threatening food security as crop yields consequently see a reduction (Taylor et al., 2009; Challinor et al., 2007; Muller, 2006).

 

Temperature

Furthermore, temperatures are predicted to increase leading to increased transpiration from plants and evaporation from soil. This will lead to a reduction in water flowing into rivers subsequently water seeping into underground aquifers thus, reducing groundwater storage (Muller, 2006). 

 

Carbon dioxide concentrations

Moreover, it is not all bad as a doubling of CO₂ concentrations it estimated to increase the yield of crops by a third (Poorter, 1993). This results from increased rates of photosynthesis. Photorespiration rates are higher at warmer temperatures thus, increases in CO₂ alone could potentially have positive effects on food security by increasing crop yields. 

 

Increased rainfall, temperature and carbon dioxide concentrations will impact plant cover which thus, affects aquifer recharge (Muller, 2006). Moreover, the cumulative effect on groundwater is remains uncertain. 

 

Impact of climate change on food security

 

Food security can be defined as a situation in which all people at all times, have social, physical and economic access to sufficient and safe food to meet their dietary needs (Thompson et al., 2010).  Thus, when food systems are stressed such that food is not available, accessible or utilization is constrained, it is said there is food insecurity (Berhanu and Oljira, 2019; Thompson et al., 2010).

 

Climate change has a significant impact on food security across Africa but particularly in sub-Saharan Africa due to their high dependency on rain-fed agriculture (Niasse et al., 2004) with irrigation constituting just 5% of crop cultivation (Ringler et al., 2010). Climate change will almost certainly reduce crop yields threatening food security (Kotir, 2010). The map below shows the distribution of undernourishment in Africa currently – as you can see, sub-Saharan Africa is amongst the most undernourished with an estimated 32% deprived access to food (Shah et al., 2008).

Figure 2: Map of Africa showing the proportion of the population undernourished in each country using 2000-2002 as the baseline period

Source: Hall et al., 2017

Moreover, what must also be considered is the fact that food security is not defined solely in terms on accessibility (Thompson et al., 2010). Although accessibility is thought to decrease, but also food is not sufficient to meet dietary needs. Cassava is used as a famine reserve crop and a source of calories but is linked to the disease, konzo. During periods of drought when other crops fail, cassava is the only means of meeting daily dietary requirements. Moreover, this resulted in a konzo epidemic across sub-Saharan Africa which was devastating (Tylleskär, 1994). Therefore, tackling the hunger games (again), is not as easy as improving accessibility to food but access to safe and nutritious food (Thompson et al., 2010).