A Homogeneous Africa?

One of the first pieces I read when researching the topic of water and food in Africa was a satirical essay by Binyavanga Wainaina titled ‘How to Write About Africa’ where the author emphasises a plethora of preconceived discourses people have about the continent’s people and landscape (Wainaina 2005). The quote ‘treat Africa as if it were one country’ is particularly fruitful for discussions regarding the topic of this blog because in doing so, it fails to acknowledge the physical, climatic and political differences exhibited across Africa; in popular discourse, it is not uncommon for Africa to collectively be referred to as dry and lacking freshwater, consequently disregarding the above differences and their role in determining access to water.

This post will therefore outline some of the crucial factors that influence the distribution and access to water across Sub-Saharan Africa (SSA), thereby dismissing any notions about a homogeneous Africa.

Climatic and Physical Setting

Global patterns of atmospheric circulation generally control the climate of east and southern Africa. My last post briefly mentioned an over-reliance on rain-fed irrigation and so the spatial and temporal distribution of rainfall across SSA is important to delineate.

Rainfall is largely seasonal throughout SSA as a result of the movement of the Inter-Tropical Convergence Zone (Nicholson 2018), a belt of low pressure situated near the equator that brings with it heavy rain and thunderstorms. Areas closer to the equator typically receive more rainfall as the ITCZ effects them for larger proportions of the year, whilst peripheral regions, mainly towards the north, experience little annual precipitation (Figure 1). Variability in rainfall is also controlled by El Nino-Southern Oscillation (ENSO) which prompts unusually dry conditions in southern Africa and wet conditions in the east of Africa from December-February (Janowiak 1988).  

Figure 1. A map of annual rainfall (mm) across the continent of Africa. (Source: UNEP)

The physical landscape of regions in Africa also contributes significantly to rainfall patterns. For example, despite the moisture-laden air that originates from the Indian Ocean, eastern Kenya receives little rainfall as much of this moisture is taken when the air advances over the highlands of Mozambique (Kendrew 1961, cited in Taylor 2004). These highlands also generate orographic rainfall across the north-east of the island, contrasted by the drier regions to the west which are under a rain shadow depleted of the humidity of the south-eastern trade winds.

Groundwater

Whilst true that there is a lack of surface water across most of the continent, the vast stores of groundwater situated in Africa (Figure 2) seem to dispel connotations of Africa as ‘water scarce’. Instead, these stores may offer an alternative to regions exhibiting undesirable climate variability; the successful utilisation of groundwater has been posited as one of the best ways to provide a safe and reliable source of water for rural communities (e.g. Giordano 2009) due to its slow response to meteorological conditions and its general absence of contaminants (MacDonald et al. 2012). As such, the role of groundwater in supporting food production and reducing poverty is critical. Unfortunately, its uneven distribution, compounded by a limited knowledge of groundwater, evident from the inadequate detail included in the IPCC Fourth Assessment Report on water (Bates et al. 2008), demonstrates a necessity to precisely characterise its resource. This will help inform strategies that can help the roughly 80% of Africa’s population reliant on groundwater supplies for their water needs (Callow and MacDonald 2009).

Figure 2. A map outlining the distribution in groundwater storage in Africa. (Source: BGS)

To summarise, an accurate assessment of the challenges facing people who are unable to access a safe supply of water must recognise that these particular challenges are diverse in their nature. So, where distribution of rainfall is unable to fulfil the agricultural needs of populations, ready access to an alternative like groundwater is vital; if access is also limited, this is where the real problem arises.

My next post will attempt to shift the conversation to metrics of ‘water stress’ and the importance of conceptualising this for food security. Further posts will delve deeper into the significance of groundwater for agricultural purposes.