The Full Picture - Is the glass really empty?

If asked to reflect on water in Africa, what images come to mind? Children walking miles to collect unclean water, a lack of water, droughts, aridity…

These images can be summarised into three key misrepresentations which need to be addressed:

1. Africa has a limited supply of water 
2. Africa's water resources are solely dependent on rainfall
3. Water in Africa being primarily for domestic use 

These images are misrepresentations of Africa, an issue discussed in last week's post. The issue is water scarcity in Africa, is one of distribution which is affected by the variability of different factors upon the African continent – seasons, climates, elevations and geologies etc. In fact, there are some places in Africa which are abundant in water resources - countries across have rainfall surplus for example (UNEP, 2012.) Whilst others in arid and semi-arid regions receive very low levels of precipitation.

Explanation of Africa's Climate and Precipitation Variability:

Africa has the most variable water resources (see Table 1) and most variable river discharge in the world (McMahon et al, 2007.) Rainfall is increasingly variable across Africa. Figure 1 shows the distribution and mean annual rainfall across the continent. The highest values are at the equator (shaded in blue hues.) The magnitude of rainfall declines the further northwards and southwards from the equator. This explains the arid locations of the Sahara Desert in the North of Africa and Kalahari Desert in the South - highlighted in red.  

Figure 1: Rainfall patterns across the
African continent (Masih et al, 2014.)

An explanation for precipitation variability in Africa is the 'Intertropical Convergence Zone' (ITCZ). This refers to the meeting point of two Hadley cells. As the two air masses collide, moist air is forced upwards triggering condensation and the heavy precipitation associated across the band of the equator. This also affects the planetary winds and pressure systems in the North and South of the continent (Nicholson, 2018.) As the Hadley cells move poleward, they descend delivering small amounts of precipitation.  The ITCZ determines biomes and thus the arable land available. Thick rainforest is found at the equatorial belt, transforming into grasslands, savannahs and arid deserts – reflecting a latitudinal symmetry. 

Precipitation tends to occur once or twice annually, on a seasonal basis in July and January. The rainy seasons are associated with the movement of the ITCZ. Countries such as Senegal, Sudan and Ethiopia receive their rainy season during the northern hemisphere's summer. Once the ITCZ moves southerly during the northern hemisphere's winter, countries south of the equator receive heavy rainfall including Madagascar, Tanzania, Zambia (Ziegler et al, 2013.) 

Table1: Total and Proportional Renewable
Water Resources in Africa (UNEP, 2010.)

Levels of precipitations are also dependent on topographical variability which has an impact on land use and hydrological basins. Higher elevations are typically cooler and therefore have higher levels of orographic precipitation. For example, at the Ethiopian Island Highlands, the climate is cool enough to receive snow.

The variability of African water distribution will become more volatile with climate change. Climate change affects physical systems and most importantly affects food security through the disruption of growing seasons. In some cases, climate change can intensify precipitation, but heavier and fewer rainfalls deplete nutrients in the soil and can result in soil erosion heightening food insecurity in places of rainfall surplus.

Aside from physical factors, socioeconomic factors can explain the variability of water resources. Indicators in sub-Saharan Africa demonstrate that 90% of the rich quintiles in urban areas have improved water sources and over 60% have access to piped water whilst in rural areas piped water facilities are practically non-existent (UN, 2012.) Other socioeconomic factors include poor governance through failures to implement essential water management techniques, corruption and economic scarcity.

How does Africa use its water resources?:

Table 2: Population and Water Withdrawal
by Sector per Continent (Wada el al, 2011.)

    The majority of Africa's water use is        for agricultural purposes. Agriculture        makes up for 83.1% of Africa’s total        water usage, domestic uses stands at        12.6% and industrial purposes at            4.3% (Wada et al, 2011.) To further        strengthen the importance of the            agricultural sector in the African               continent, 23% of sub-Saharan                 African   GDP is made up from                agriculture  (Goedde, 2019.)

Is Water scarcity a continental issue?

Malin Falkemark’s method of measuring levels of water stress consisted of measuring freshwater flow levels from the mean annual river runoff  (Falkemark, 1989.) Figures below 1700 m³ per person per year show water scarcity whilst figures below 500 m³ per person per year highlight absolute water scarcity. Alternatively, water scarcity defined as ‘a shortage in the availability of freshwater relative to demand,’ by Richard Taylor (Taylor, 2009: 237) allows for groundwater stores to be considered. Groundwater storage trends explain how seemingly water-stressed countries can produce the high levels of agriculture. North African agriculture is partly the result of the Nubian Aquifer, allowing one of the most arid areas in Africa to be agriculturally feasible.

After demystifying these assumptions, the relationship between food and water becomes more apparent given Africa's high proportion of water usage attributed to agricultural practices. Additionally, a large proportion of African likelihoods are dependent entirely on agriculture (include labour force figure.) Water has great repercussions on food production and food security which in turn aids other economic indicators of development – fundamental for the achievement of the Sustainable Development Goals (SDGs.)