There is a lot of rainfed agriculture in many parts of Africa. Many people also depend on livestock and are pastoralists – taking their herds to where they can graze. But with climate change the grazing land is disappearing and becoming desertified. This means families will have to take their herds farther and farther away from the villages to find fodder.
Let’s look more closely what climate change may mean for Sahelian agriculture, livestock and fisheries.
Researchers think that yields could decline for maize and beans (two key staple crops in Africa) by 20-40% in areas where they can grow well compared to averages from between 1970-2000.
Western Africa is a highly-vulnerable region, with significant (>10%) reductions forecast in suitable areas for growing maize, sorghum, finger millet, groundnut and bananas. These are important staple crops for food security – but they also generate income. Therefore, peoples’ food intake and livelihoods will be affected.
Pests and diseases increase at higher temperatures and humidity. This means climate change will likely increase the frequency of new pest introductions and major pest outbreaks. This in turn will potentially increase the risk of harmful pesticide residues in the food that will be produced and consumed in the region.
Humidity is shown to result in increased risk of diseases from mildew, leaf spot, bacterial stem and root rot. And hot and dry environments enable aphids, borers, bollworm, beetles and whitefly to thrive.
Also, nematodes are sensitive to environmental disturbances. It’s very likely that any changes to nematode communities induced by warming may have a considerable influence on soil ecosystem function. Whitefly populations are also expected to expand to regions where increasing temperatures will eliminate frosts, allowing year-round breeding. The effects of such changes will probably be profound and may lead to substantial ecosystem-wide changes.
For example, livestock rearing is one of the main livelihoods activities in Africa. Livestock herding contributes up to 10-15% of GDP in Burkina Faso, Chad, Mali and Niger, and, in Mauritania, 50% of the population is pastoralist.
Goat, camel, sheep and cattle herding are essential for rural livelihoods - this means for employment, meat and milk, earning income and being able to save.
Climate change can affect livestock in three ways: it affects water availability, heat stress, and the quality and quantity of feed available.
Parasites and pathogens that come with higher temperatures and increased humidity will change the vulnerability of animals and alter the ecosystems we all live in.
Some important livestock diseases, such as bluetongue, have already increased because of climate change and changes are expected in priority diseases such as trypanosomosis (costs farmers in east Africa $2 billion a year), East Coast fever (kills one animal in Africa every 30 seconds) and Rift Valley fever (reduced exports from Africa by 75%).
Pasture, fodder, forest products and water that feed livestock are directly affected by climate variability, impacting productivity and herd migration routes.
Water-borne bacteria or viruses have the potential to spread at faster rates than in land-based systems. We have seen reports of two major climate-sensitive diseases spreading quickly recently, the epizootic ulcerative syndrome (EUS) in fish have increased since 2007 in Botswana, Namibia and Zambia and shrimp white spot disease (WSD) has also been more frequent since 2011 in Mozambique.
In the Sahel, for example, characin and perch are important inland species, and they are increasingly affected by changes in water quality and dissolved oxygen content, as well as water levels.
Climate change also affects fish migrations. Fish tend to migrate to rich flood plains for feeding and breeding and this changes the availability of fish to local populations. Finally, as water-borne pathogens can spread faster than terrestrial pathogens, disease levels are rising in fish and human populations.