Rain for African Farmers

Changing climate 

Africa and Sub-Saharan Africa in particular are highly vulnerable to climate change. As a consequence of greenhouse gas emissions, our planet is heating up (Carter, R.C. and Parker, A). According to the The Intergovernmental Panel on Climate Change (IPCC) in 2007 humans` influence on climate change can no longer be denied. Figure 1 shows the temporal growth of rising air temperature in the years since 1870. As you can see the global air temperature has risen up to 0.75°C in 2015. Rising temperatures mean that areas will get drier, droughts will increase and more extreme weather will occur. Also the hydrological cycle is linked to certain aspects of climate change within temperature and radiation balance. (Batels et al., 2008).

Figure 1: Global air temperature (http://www.cru.uea.ac.uk/).

No rain, no crops

Africa is highly dependent upon the agricultural sector. The value added in the GDP is very high, as in Chad where 52,39% of the GDP was generated by the agricultural sector (The World Bank). Cash crops are essential parts of the African economy. But to grow the crops a huge amount of water is needed. Most of the Sub-Saharan countries suffer with little rainfall. Farmers are using irrigation systems, dependent on groundwater to grow their crops. The demand for freshwater is rising. As the rainfall is characterised for high variability, the population relies on shallow or deep groundwater. R. Carter and C. Bevan estimated the number affected by one billion people. These reservoirs need to be recharged by the annual rainfall to ensure water supply.

Table 1: Rate of mean annual rainfall and rainfall range in Sub-Saharan countries (Source: ARTES) By Carter, R.C. and Parker, A., (2009).

Table 1 highlights the mean annual rainfalls in certain countries of Sub-Saharan Africa in context with the rainfall range. The deviation between the mean annual rainfall and the range is enormous. Countries like Niger have got 45% less rainfall than the mean rainfall should be. Any changes in the annual rainfall either temporal or spatial distribution, are expected to influence the water balance (Carter, R.C. and Parker, A., 2009.). This of course has a huge on impact on African farmers, which are dependent on the agricultural sector. As I said before the rainfall in Africa is characterised by high variability between years, but trough, climate change, the variation of rainfall will be more extreme than is it now. Carter, R.C. and Parker, A. believe “the question of the likely impact of climate change on renewable groundwater resources is highly relevant, but under-researched”.

References: 

Carter, R. C. & Bevan, J. E. (2008) Groundwater development for poverty alleviation in sub-Saharan Africa. In: Applied Groundwater Studies in Africa (ed. by S. Adelana & A. M. MacDonald), 25–42. IAH Selected Papers on Hydrogeology no. 13, CRC Press, Taylor & Francis, UK.

Carter, R.C. and Parker, A., 2009. Climate change, population trends and groundwater in Africa. Groundwater and climate in Africa: a review. Hydrological Sciences JournalVol. 54(4), pp. 676-689.