Climate change may lead to the undoing of tireless efforts made over the years to boost agricultural production and improve food security.
The consequences of climate change are likely to be felt by the world’s poorest regions first and most severely. This may explain why efforts by high-income countries (arguably the largest greenhouse gas emitters) to slow or reverse this impact has been lacklustre at best. Sub-Saharan Africa is particularly vulnerable to climate change on many levels, including the threat of freshwater sources becoming depleted and hunger and malnutrition levels becoming exacerbated. Therefore, it may be left up to Africa and the rest of the developing world to begin adapting to climate change or be left to deal with the impending devastation.
Since the 1970s, land temperatures across Africa have been increasing consistently at around 0.4 °C per decade 1. Future temperatures are also expected to rise, but at a rate that is twice that of the rest of the world (between 2°C and 6°C); especially in the interior parts of the continent like the Sahel region1. Sea temperatures are also rising, although this time increasing less than the global average (0.6°C to 0.8°C). This is seen in the northern Atlantic, the north-west and south-west Pacific, and the Indian Oceans 2. At the 2015 UN Climate Change Conference (before Trump pulled the US out), attendees agreed to limit temperature increases to “well below 2°C above pre-industrial levels”, so as to avoid the most extreme worst-case climate scenarios3. However, temperature increases are unfortunately expected to continue for the foreseeable future, regardless of whether greenhouse gas emissions were to stabilize or decline altogether 4.
Alongside rising temperatures is the problem of erratic rainfall. Africa now experiences rainfall patterns that are both above and below normal levels; leading to extremities of wet and dry periods that cause droughts and flooding 5. For instance, while Southern Africa is experiencing decreased rainfall, some parts of East Africa, especially the highland areas, are facing heavier rainfall. This variation can even be observed in the same country.
Should the average global temperature rise by 2 °C above pre-industrial levels, rainfall could be up to 25% lower in semi-arid regions.
Such climate variability can be detrimental to the livelihoods of small-scale farmers, who carry out the bulk of agricultural activities in Africa. Farmers often lack the capacity to adapt quickly enough to climate change, mainly due to poor infrastructure. When you add climate change to the existing stresses that farmers already face (low market access, inefficient transport networks, inadequate postharvest facilities), the negative impact on food security and public health can be catastrophic. Small-scale farming communities make up two-thirds of the three billion people in rural areas across the developing world; and their contribution to the global food supply is substantial 6. However, according to all indicators, the negative impact of climate change on smallholder agriculture is real. For example, yields of rain-fed crops are expected to decline: up to 22% for maize and 8% for cassava 7. This is significant for Sub-Saharan Africa, when considering that 95 percent of crops grown in the region are rain-fed 8.
Small-scale farmers face the threat of decreased crop yields, which will affect the food security of the entire continent.
Many of Africa’s staple crops such as maize, rice, sorghum, wheat, millet and cassava are expected to one day reach their upper thermal limit; meaning the temperature at which yields will start to decline. Current estimates place yield losses anywhere between 2 ½ and 16 percent for every 1°C of seasonal temperature increase 9. Add this to the fact that the excess carbon dioxide in the atmosphere may affect the nutrient content of many crops, rendering them deficient in key micronutrients like zinc and iron 9. This will only fuel the already high disease burden, which will come with its own consequences.
Agriculture will not be the only sector to suffer; as climate change is also very much a public health issue. For example, warmer conditions in some regions will likely increase the incidence of vector-borne diseases like malaria; while increased flood conditions can create a thriving environment for water-borne infections like cholera, and other diarrhoeal infections that already kill millions of children from poor families 9. It is safe to say that these public health problems will be magnified by existing conditions such as poverty, lack of health and hygiene infrastructure, and of course food insecurity. Undernutrition (often used synonymously with “malnutrition”) refers to the insufficient intake of both nutrients and energy for an individual to remain healthy 10. This is already a long-standing problem in Africa; and with climate change threatening to destroy what is left of rain-fed agriculture, it is likely to get a ton-load worse 9 . Around 10 million more children across the world will become undernourished because of climate change 9 . A child’s mortality rate in Sub-Saharan Africa is 14 times higher than that of a high-income region; so, you can guess where most of these undernourished cases will be from 9.
Climate change is likely to lead to more children suffering from undernutrition
Climate change will also affect water availability. A combination of increased temperatures and irregular rainfall makes water resources extremely vulnerable. For instance, longer dry seasons could mean a depletion of surface water. Observations show that freshwater sources in Sub-Saharan Africa are already scarce, and current water management systems leave much to be desired. In dry topical areas, freshwater is expected to decline by anywhere between 10% and 30%2. This is likely to intensify the frequency of droughts, which apart from the obvious impact on agriculture and health, will also affect the use of hydropower to generate electricity – especially in Southern Africa where it contributes significantly to the power grid 11. Further, decline in rainfall across Southern Africa will almost certainly deplete surface water; and higher temperatures will almost certainly increase groundwater evaporation 12. This will most certainly cause problems for sustainable agricultural production to bolster food security going forward 13. Rising temperatures may cause most rainwater to evaporate before it even gets the chance to replenish the groundwater. Up to 70% of rainfall will evaporate before ever reaching crops; crops that directly depend on moisture from the rain that remains in the soil 14.
The Central African region, which includes the Democratic Republic of Congo (DRC) is said to be ‘the wettest place on Earth’ during its rainy season. The Congo Basin is the largest water catchment in Africa and the Congo rainforest is the second largest tropical forest in the world.
While some regions are expected to suffer from a lack of water, many coastal regions will find themselves having too much of it; as they face rising sea levels that is likely to contaminate what’s left of the freshwater needed for agriculture and to manage the ecosystem 2. Then there are the extreme weather events like flooding; which will undoubtedly cause loss of life and damage to infrastructure, which disrupts and further delays economic development. Between 1980 and 2016, Southern Africa got hit with a bill of $10 billion dollars due to climate-related disasters; as well as the headache of rehousing 2 ½ million people that lost their homes, plus another 140 million people that were otherwise affected 2.
The frequency and intensity of climate-related disasters are likely to increase
In a nutshell, climate change is likely to reduce the availability of freshwater sources, increase the incidence of flooding and droughts, decrease the yield and nutrient content of major staple crops, and lower the productivity of the entire ecosystem. Sadly, this list is far from exhaustive, but the full magnitude goes beyond the scope of this article. However, provided that appropriate adaptations are made, increases in agricultural production despite climate change is a possibility 8.
According to “Climate Risk and Vulnerability: A Handbook for Southern Africa” 2, there are several proposed strategies worth exploring in an attempt to adapt to the changing climate. These include but are not limited to:
- Developing and promoting drought-tolerant crop species
- Soil conservation – (tree planting, grass cover, terrace farming, trenches, mulching, alternative cropping)
- Exploiting renewable energy sources (less reliance on wood energy)
- Natural forest conservation
- Investment in value-addition and post-harvest technology
- Increasing water supply (irrigation, rainwater harvesting)
Of particular interest is rainwater harvesting, which is a useful but often overlooked method for ensuring a sustainable supply of water to cultivate rain-fed crops – the backbone of African agriculture.
Domestic rainwater harvesting underground tank in South Africa. Water collected from the ground surface is channelled into an underground tank
Rainwater harvesting can be done on a small-scale using several methods like terracinga, which helps retain soil moisture; or by building dams/ditches, which help funnel run-off water into crop fields; or simply storage systems (tanks, ponds etc.) to conserve water 14. These methods are already being practised in East African countries like Eritrea, Ethiopia, and Sudan 14. Rainwater harvesting projects in Kenya and Tanzania dating back to the 1980s have already shown the ability of the method to improve crop yields and even quadruple per hectare productivity 15. Used together with irrigation systems like dripb, spatec, and sprinklers, rainwater harvesting has the potential to significantly improving water usage in agriculture. Given the long dry spells many farmers already face, they can indeed benefit from this and other innovative systems that improves the way rainwater is utilized; therefore, ensuring farmers achieve a more sustainable harvest in the long term.
- Engelbrecht, F., Adegoke, J., Bopape, M., Naidoo, M., Garland, R., Thatcher, M., McGregor, J., Katzfey, J., Werner, M. & Ichoku, C. (2015). “Projections of rapidly rising surface temperatures over Africa under low mitigation”, Environmental Research Letters, vol. 10, no. 8, pp. 085004.
- Davis-Reddy C, Vincent K. (2017). Climate Risk and Vulnerability: A Handbook for Southern Africa (2nd Edition). CSIR, Pretoria, South Africa. Available at: https://www.weadapt.org/sites/weadapt.org/files/2017/november/sadc_handbook_second_edition_final_full_report.pdf
- Nino, F.S., (2015). UN Climate Change Conference Paris 2015. United Nations Sustainable Development. Available at: https://www.un.org/sustainabledevelopment/climatechange/
- Stocker, T., Qin, D. & Platner, G. (2013), Climate Change 2013: The Physical Science Basis. Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Summary for Policymakers, Cambridge University Press, Cambridge, UK.
- MacKellar, N., New, M. & Jack, C. (2014), “Observed and modelled trends in rainfall and temperature for South Africa: 1960-2010”, South African Journal of Science, vol. 110, no. 7 & 8, pp. 51-63.
- Innovation Forum (2018). What does the future look like for sustainable smallholder farms? Innovation Forum Editorial Team. Available at: https://innovation-forum.co.uk/analysis.php?s=what-does-the-future-look-like-for-sustainable-smallholder-farms
- Campbell, M.M., Casterline, J., Castillo, F., Graves, A., Hall, T.L., May, J.F., Perlman, D., Potts, M., Speidel, J.J., Walsh, J., Wehner, M.F., Zulu, E.M., (2014). Population and climate change: who will the grand convergence leave behind? The Lancet Global Health 2, e253–e254. https://doi.org/10.1016/S2214-109X(14)70021-X
- Müller, C., (2013). African Lessons on Climate Change Risks for Agriculture. Annual Review of Nutrition 33, 395–411. https://doi.org/10.1146/annurev-nutr-071812-161121
- USAID (2017). Risk Expands, But Opportunity Awaits: Emerging Evidence on Climate Change and Health in Africa. weADAPT. Available at: https://www.weadapt.org/sites/weadapt.org/files/2017/may/170414_atlas_project_ssa_health.pdf
- Maleta, K., (2006). Undernutrition. Malawi Med J 18, 189–205.
- Field, C.B., Barros, V.R., Mach, K. & Mastrandrea, M. (2014). “Climate change 2014: impacts, adaptation, and vulnerability”, Working Group II Contribution to the IPCC 5th Assessment Report – Technical Summary, pp. 1-76.
- Gordon, C., Nukpeza, D., Tweneboah-Lawson, E., Ofori, B., Yirenya-Taiwiah, D., Ayivor, J., Koranteng, S., Darko, D. & Mensah, A. (2013). “West Africa – Water Resources Vulnerability Using a Multidimensional Approach: Case Study of Volta Basin. Climate Vulnerability: Understanding and Addressing Threats to Essential Resources”, Elsevier Inc., Academic Press, 283–309.
- UN-Habitat (2013). State of the World’s Cities 2012/2013. Prosperity of Cities, United Nations Human Settlements Programme, Nairobi, Kenya.
- Rockström, J., Falkenmark, M., (2015). Agriculture: Increase water harvesting in Africa. Nature News 519, 283. https://doi.org/10.1038/519283a
15. Rockström, J., Falkenmark, (2000) Semiarid Crop Production from a Hydrological Perspective: Gap between Potential and Actual Yields. Crit. Rev. Plant Sci. 19, 319–346