Toward climate-smart agriculture in West Africa: a review of climate change impacts, adaptation strategies and policy developments for the livestock, fishery and crop production sectors

Observed climate change impacts and projections for the livestock sector

The fifth assessment report of the IPCC reports that the vulnerability of livestock keeping communities may be amplified as climate change interacts with other stressors of the livestock sector such as rangeland degradation; increased variability in access to water; fragmentation of grazing areas; sedentarization; changes in land tenure from communal toward private ownership; in-migration of non-pastoralists into grazing areas; lack of opportunities to diversify livelihoods; conflict and political crisis; weak social safety nets; and insecure access to land and markets [15]. It is reported that the changing frequency of extreme climate conditions such as droughts and floods has had greater impacts on livestock and the associated livelihoods than average trends from climate change (that is, average change in precipitation and temperature) [16, 17]. For example, repeated occurrence of droughts in the Sahel has led to adoption of agro-pastoralism (combination of crop farming and livestock rearing within the same farm) among the pastoralists who were once solely depending on livestock for their livelihood [7]. Similarly, crop farmers have diversified in the past two decades into rearing livestock due to repeated crop failure associated with droughts [18].

Climate change is expected to affect livestock at both the species and breed levels, although this is a major research gap. Specific impacts of climate change on livestock may include changes in availability and quality of forage resources, access to water, species and breeds of livestock that can be kept, livestock mobility and animal diseases (emerging and re-emerging diseases) [19]. A hotter and drier climate in the arid and semiarid zones of the region may favor livestock species and breeds that thrive well under heat stress and those with less water requirements such as small ruminants (sheep and goats) and camels [20]. This is already the case in West African Sahel with the shift in livestock species from cattle before the droughts of early 1970s and 1980s to sheep and goats [21] as the latter (small ruminants) are less costly, hardier, require lower feed and reproduce faster than cattle. A hotter and drier climate in subhumid and humid zones will modify the habitat of the endemic livestock breeds which are resistant to trypanosomiasis, the major animal disease in the zones, and will consequently alter the breeds that can be kept. However, climate change impacts on forage availability and quality may include: changes in herbage growth, changes in floristic composition of vegetation, changes in herbage quality and changes in the importance of crop residues as animal feed [22]. Generally, the impacts of climate change on herbage growth will depend on the plant species as increase in future CO₂ levels may favor different grass species than currently, while the opposite is expected under associated temperature increases [23]. The consequences of these impacts for livestock producing households depend on the development pathway taken, such as population growth, changes in income levels, growth in regional trade and degree of technological development [22]. Meanwhile, the current low adaptive capacity is expected to make the region particularly vulnerable to climatic shocks such as drought and flood. In general, the impacts of climate change on the poor livestock keepers will be context-specific, reflecting factors such as geographic location, socioeconomic profiles, prioritization and concerns of individual households, as well as institutional and political constraints [24].

A critical challenge that will face livestock keepers particularly pastoralists is the inevitable switch from their livelihoods that are intertwined with their customs and traditions over generations. Some climate models predict growing wetness in large areas of key cattle-producing countries like Niger, Nigeria and Mali. High rainfall could make these areas inappropriate for cattle production due to increase in disease pressure. The consequences will be very grave in acquiring much needed skills in exclusively growing crops particularly those that are adapted to wet conditions which the herders have not been accustomed to. In addition to threats to their cattle, the infrastructure with regard to houses and roads is adapted to dry conditions. Persistent rainfall will pull down the characteristic mud houses and fragile roads. In the meantime, however, livestock will remain an important asset to help households manage climate risks.