Alongside Climate Change: Other Human-Induced Risks to African Water Supply

Although my blog has focused on anthropogenic climate change so far, there are other risks that have to be considered to give a full picture of future SSA water supply. One of these risks is soil degradation resulting from desertification.

As discussed by Warren et al. in 'The future of deserts', a number of factors will contribute to desertification in the future: population increase, demand per/capita for water increasing (from rising living standards), continuing oil development and ambitious water management schemes changes. All of the above apply directly, and potentially most significantly worldwide, to Sub-Saharan Africa.

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Feddema studied the impacts of soil degradation alongside climate change. Feddema used 'a GCM global warming scenario, a newly derived soil water-holding capacity data set, and a worldwide survey of soil degradation between 1950 and 1980' to simulate the future effects of climate change and soil degradation on African water resources between 2010 and 2040. 

On a continental scale, climate change had a much large impact on water resources. This is perhaps unsurprising, as all of Africa is susceptible to increasing temperatures and changing rainfall patterns, whereas only specific areas are susceptible to desertification and soil degradation. To consider this, Feddema then focused on areas where decertification could potentially be present (climates alternating between wet and dry). Here, the impacts of anthropogenic changes to water resources through desertification and climate change 'can be expected to be on the same order of magnitude'. Across the whole continent, Feddema's research suggests there will be a small increase in rainfall (this will have huge spatial variation within Africa) but a large increase in evapotranspiration resulting in drying. Furthermore to having a wet and dry climate, soil degradation will be most intense in areas with a high population density resulting in lowered water storage capacity. As such, there will be a higher water surplus in the wet season when the soil can hold less water, and water deficits in dry seasons will increase because of reduced soil water availability (as less was absorbed in the wet season). 

The overall result of these scenarios is 'an intensification and extension of drought conditions during dry seasons'.

This is an example of how climate change (increasing temperatures and changing rainfall patterns) is not the sole cause of increased water stress in Africa. Desertification is exacerbated by climate change, and many other factors, to provide specific areas of Africa, such as the Sahel region, multiple water problems. 

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