It was not until Anton Earle asked the question, when I learnt that Johannesburg is actually wetter than London. I had to cross check online just to make sure – Johannesburg receives an average annual rainfall of 604 mm per year, compared to London’s 593 mm. But why then does London look and seem wetter than Jo’burg?
Anton, who happens to be a water expert, and also a Director at the Stockholm International Water Institute (SIWI) explained this to be a result of evaporation. There tends to be relatively much less evaporation in London compared to Jo’burg – so moisture is retained for much longer in London.
In fact, as Anton explained, water in sub-Saharan Africa tends to evaporate three times faster than in Europe. Therefore, sub-Saharan Africa requires more water use efficiency, as well as harvesting – particularly for agriculture, in order to achieve food security.
Yet much of African agriculture is almost entirely dependent on rain-fed agriculture, which suffers from the curse of either too much or too little rainfall. The forces of nature hardly ever provide that precise amount of rainfall that perfectly suits agricultural production.
And with extreme weather phenomena becoming more of a new norm, the variation in yields and production have become particularly severe. This reflects the extreme vulnerabilities of production systems in sub-Saharan African agriculture.
Yet there is very minimal investment that has gone into developing irrigation infrastructure. Recent studies point out that 13 million hectares in Africa are under irrigation, which is 6% of the continent’s total cultivated land. In South Africa, 12.9% of cultivated land is under irrigation – which is 1.7 million hectares.
Perhaps part of the reason for this low irrigated hectarage is the exceptionally high levels of investment required to develop irrigation infrastructure. Water experts argue that developing a hectare of irrigation requires up to US$8 000 per hectare. This is well beyond the reach of many small to medium scale farmers, who form the bulk of sub-Saharan African primary agriculture.
Part of the reason for this high investment cost has been explained by the unfavourable topography and bio-physical terrain. What is even more discouraging, however, is that such significant investment will unlikely be made if returns in agriculture remain low.
Analysts believe that doubling area under irrigation will take an investment cost of US$32 billion – which would expand sub-Saharan Africa’s irrigated area by 16.3 million hectares, with an average return of 6.61 percent.
With that said, and against the reality of climate change, what then becomes of the much hoped for Green Revolution for Africa? Whereas poor infrastructure, lack of political will, and corruption, among other factors, led to a false start of the Green Revolution in Africa, the centrality of climate change to the discourse of agricultural development means irrigation has become an integral part of future growth path of the sector.
This emerging reality seem to suggest that Africa’s Green Revolution in will not follow a path comparable to that of Asia. It will be driven by the evolution and revolution in climate smart agriculture.