S ub -S aharan A frica : F ood P roduction at R isk
Figure 3.17: Observed cattle density in year 2000
A study of pastoral farmers’ responses to climate variability in the Sahel, Barbier, Yacoumba, Karambiri, Zorome, and Some (2009) reports that farmers are more interested in the specific characteristics of a rainy season, not necessarily total rainfall, reflecting the finding in some of the literature on crops about the importance of the temporal distribution of rainfall. Increased unpredictability of rainfall poses a threat to livestock (Sallu et al. 2010). Livestock is vulnerable to drought, particularly where it depends on local biomass production (Masike and Ulrich 2008), with a strong correlation between drought and animal death (Thornton et al. 2009). Specific factors that are expected to affect livestock include the following: • The quantity and quality of feeds: through changes in herbage because of temperature, water, and CO2 concentration, and species composition of pastures, which in turn can affect production quantity and nutrient availability for animals and quality. • Heat stress: altering feed intake, mortality, growth, reproduction, maintenance, and production). • Livestock diseases, both due to change to diseases themselves and the spread of disease through flooding.
Source: Adapted from Robinson et al. (2007) with updated data, with permission from Veterinaria Italiana. Further permission required for reuse.
Regional climate change is found to be the largest threat to the economic viability of the pastoral food system (Dougill et al. 2010). However, pastoral systems have largely been ignored in the literature on climate impacts, which has a bias toward the effects of climate change on crop production (Dougill et al. 2010; Thornton, Van de Steeg, Notenbaert, and Herrero 2009). Less is known, therefore, about the effects of climate change on livestock (Seo and Mendelsohn 2007). Climate change is expected to affect livestock in a many ways, including through changing means and variability of temperature and precipitation (Thornton et al. 2009), thereby potentially placing livelihoods dependent on the sector at risk (Box 3.4). The savannas and grasslands in which pastoral societies are often located are typically characterized by high variability in temperature and precipitation (Sallu, Twyman, and Stringer 2010). The pastoral systems of the drylands of the Sahel depend highly on natural resources, such as pasture, fodder, forest products, and water, all of which are directly affected by climate variability (Djoudi, Brockhaus, and Locatelli 2011). Sallu et al. (2010) note that historical drought events in the drylands of Botswana have reduced the diversity and productivity of vegetation, thereby limiting available grazing and fodder resources.
• Water availability: especially considering that water consumption increases with warmer weather. • Biodiversity: the genetic variety of domestic animals is being eroded as some breeds die out, while the livestock sector is a significant driver of habitat and landscape change and can itself cause biodiversity loss. (Thornton et al. 2009; Thornton and Gerber 2010). The factors listed above may interact in complex ways; for example, relationships between livestock and water resources or biodiversity can be two-way (Thornton et al. 2009). The ways in which climate change impacts interact with other drivers of change (such as population increases, land use changes, urbanization, or increases in demand for livestock) need to be considered (Thornton et al. 2009). Available rangeland may be
Box 3.4: Livestock Vulnerability to Droughts and Flooding The impacts of climatic conditions on livestock can be severe. As a result of droughts between 1995 and 1997, pastoralists in southern Ethiopia lost 46 percent of their cattle and 41 percent of their sheep and goats (FAO 2008). Damage to livestock stocks by flooding in the 1990s has also been recorded in the Horn of Africa, with mortality rates as high as 77 percent (Little, Mahmoud, and Coppock 2001).
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