Climate change effects on irrigation and rain-fed production

As mentioned at the end of the previous post, this entry will seek to explore how climate change might have an effect on human behaviour and choices in relation to water in Africa.

I managed to find a paper on the use of a modelling framework to explore the effect of irrigation on farm performance: ‘Endogenous irrigation: the impact of climate change on farmers in Africa’ (Kurukulasuriya and Mendelsohn 2007). The authors argue that when considering the impact of climate change, irrigation should be treated as endogenous, as opposed to exogenous, as the decision to irrigate is a choice and this is influenced by climate (Mendelsohn and Dinar 2003). Factors which influence the choice to irrigate include surface flows, soil types, and subsidies.

The Ricardian analysis, taking into account irrigation as an endogenous factor showed that warming would lead many farmers in Africa will experience net revenue losses from warming. It also showed that irrigation increases resilience to temperature change and may even realise slight gains in productivity. Therefore, by extension, climate change conditions that encourage the choice to irrigate could in fact bring about improvements in agricultural yield

In another paper by Cooper et al. (2008): ‘Coping better with current climatic variability in the rain-fed farming systems of SSA: An essential first step in adapting to future climate change?’, the effect of climate change on rain-fed farming performance (as opposed to agricultural reliance on irrigation) is explored. Rain-fed food production is the dominant source of food production and the means of livelihood for the majority of the rural poor in sub-Saharan Africa (SSA). Yet, it is vulnerable to between and within season rainfall variability, which is likely to worsen with climate change. In particular, the semi-arid tropics of Africa, where 80mil of the continent’s poorest communities live and under increasing population and livestock numbers, is also where climate variability has the most profound impacts on production. As seen below, the inherent variability increases disproportionately as one moves from the wetter to the semi-arid locations that receive between 250 and 600mm of seasonal rainfall.

Figure: Seasonal rainfall means and their coefficient of variation in Eastern

and Southern Africa.

Source: Cooper et al. (2008)

The authors suggested ways in which climate change can be coped with, in the area of agriculture, from which I have gleaned the following two learning points that I feel are rather insightful:

•  Farmers have traditionally coped with climate variability by seeking to mitigate the negative impacts of poor seasons and then fail to exploit the positive opportunities of average and better-than-average season. It is therefore important to consider climate variations holistically, and implement strategies from a long-term perspective. As said in one of my previous posts, seasons with exceptionally high rainfall may lead to groundwater recharge which may be harnessed for irrigation during dry periods.
• Coping strategies must be tailored to specific contextual factors, including physical, economic, and socio-cultural factors. For instance, some communities may be able to diversify into off-farm activities to cope with water shortage but this may be less feasible for small-holder farms in isolated and less-favoured areas if rain-fed systems in Africa. Instead, resilience in water provision to maintain agricultural productivity can be achieved by working with the available resources and present circumstances. Examples of strategies include improving water productivity and integrated management of land and water resources though more investments in farming practice would be necessary.

In the next post, I will be looking at another aspect of the relationship between climate change-water-human welfare by writing about the impact of climate change on the quality of water, till next time! :D