Abstract:

Sub-Saharan Africa’s (SSA) biggest source of GDP and livelihood is agriculture. Climate change is negatively impacting agriculture and decreasing crop yields, and agriculture in SSA has been declining for the past 50 years. In order to combat the effects of climate change, adaptations to its effects on agriculture need to be implemented. There are many different potential adaptations that should be tailored to the specific needs of individual farmers. Potential adaptations include increased crop area, increased irrigation, increased irrigation productivity, rainwater harvesting and management techniques, and genetically enhanced crops. If agriculture in SSA can successfully adapt to the changes brought by climate change, crop yields will increase and malnutrition can be decreased, and the GDP and livelihoods of SSA will no longer be threatened.

Introduction:

As climate change is causing drastic negative changes worldwide, there are many concerns on how humans will be able to successfully adapt. One major concern is feeding the growing population. The impact of climate change on agriculture varies across regions, but overall the trend is decreased crop yields. This is very worrying considering that feeding the world is already strained, especially in Sub-Saharan Africa (SSA), where almost a quarter of the world’s malnourished population lives. Agriculture in this region comprises up to 50% of gross domestic product (GDP) in some countries, according to Amy Dale. The impacts of climate change are not going to be equally distributed across all nations, and it is highly likely developing nations will suffer more from climate change than developed nations because many of these countries lack the ability to adapt as readily. According to Julius Kotir, SSA is classified as the most vulnerable to the impacts of climate change because of its dependence on agriculture and natural resources, and limited ability to adapt. SSA encompasses many developing countries where the current climate is already severe, with warm baseline climates and low precipitation. Furthermore, the available information on climate change is poor, and technological change is slow. According to a study by Kazi Farzan Ahmed, without adaptation, the long term mean yield of crops are projected to decrease in most countries, despite some projected increase in precipitation in some areas. The interannual variability of yield is also projected to increase significantly, because of the increase of inter-annual variability of growing season temperature and precipitation. The question that will be addressed in this paper is: what changes are going to needed to adapt crops to the changing climate and enhance agricultural productivity in Sub-Saharan Africa? I suggest that improved water management, new technologies in rain capture, and genetic improvement of crops will help farmers adapt to climate change and enhance the agricultural productivity of small scale farmers.

Background:

Understanding agricultural practices in SSA and how they are being affected by climate change is critical in determining adaptation techniques. The dependency of SSA on natural resources is one of the factors affecting its ability to adapt because more than 70% of the population lives in rural areas, and the livelihoods of about 85% depend on rain-fed agriculture and agriculture-based rural activities. Rainfed farming dominates agricultural production, covering around 97% of total cropland, exposing agricultural production to high seasonal rainfall variability (Kotir). According to a study by Alvaro Calzadilla,  agriculture in Sub-Saharan Africa is characterized by low yields compared to other regions in the world. Whereas Asia experienced a rapid increase in food production and yields during the Green Revolution in the late 1970s and early 1980s, in Sub-Saharan Africa per capita food production and yields remained stagnant. The failure of agriculture in SSA to increase yields had been attributed to its dependence on rainfed agriculture; low population densities; the lack of infrastructure, markets, and supporting institutions; the agro-ecological complexities and heterogeneity of the region; low use of fertilizers; and degraded soils (Calzadilla). Many of these factors can be contributed to the fact that this is still a developing country with such a dependence on agriculture and natural resources, and a lack of money and technology devoted to agriculture. Because SSA is already prone to low yields, climate change has the potential to devastate crop yields. 

Some of the biggest effects worldwide due to climate change are increased temperatures and decreased precipitation. Changes in temperature and precipitation can reduce crop productivity through various physiological mechanisms. The rates of physiological processes increase with temperature before reaching the optima and then decreasing, and therefore although crops develop more quickly in warmer conditions, the yield can potentially decline after the temperature goes past a certain threshold (Ahmed). In arid and semiarid regions and seasons, water is a limiting factor for growth. Another physiological mechanism in which crop yields are affected is through soil erosion and loss of soil moisture. A potential decrease in growing season precipitation can reduce soil moisture available to rainfed crops, and the resulting water stress can lead to a decrease in crop productivity (Kotir). Therefore because of SSA’s high dependency on rainfed farming, changes in the region’s temperature and precipitation may affect crop yields immensely. 

Decreasing agriculture production:

In SSA, agricultural productivity has been steadily declining over the last 50 years and has seen the slowest record of productivity increase in the world. This dismal performance in the agriculture sector is due to long standing issues such as a lack of demand for irrigated products; poor market access and supporting institutions; low population densities; low incentives to agricultural intensification; unfavourable topography; low quality soils and inadequate policy environments (Kotir). This dismal performance is thought to be significantly exacerbated by climate change, and could severely worsen the livelihood conditions for the rural poor and increase food insecurity in the region. It is likely that the region will not be able to adapt quickly enough to the changes brought by climate change, considering that many of these impacts will occur in an area with high population growth projected to grow from 900 million people in 2005 to about 2 billion by 2050 (Kotir). This increase in population would increase agricultural consumption by 2.8% annually until 2030, and by 2.0% annually from 2030 to 2050. During these same periods, agricultural production is projected to increase by 2.7 and 1.9% per year, as a consequence, net food imports are expected to rise. This would cause the region to suffer greatly in terms of GDP and livelihoods. These high population growth rates, especially in rural areas, increase the challenge of reducing poverty and raise pressure on agricultural production and natural resources. Rural poverty accounts for 90% of total poverty in the region, and approximately 80% of the poor still depend on agriculture or farm labor for their livelihoods (Calzadilla). Agriculture plays a central role in supporting rural livelihoods and economic growth over most of Africa, supporting between 70 and 80% of employment and contributing an average of 30% of GDP, and 55% of the total value of African exports (Kotir). These crop yield losses combined with an increased population will severely compromise food security in Africa. 

Climate change is expected to increase the frequency of droughts, raise average temperatures, and threaten the availability of freshwater for agricultural production. Rainfall and temperature play a significant role in determining agricultural production and thus the economic and social being of rural communities since such a large portion depends on rainfed farming. The global mean surface temperature has increased by 0.74 °C over the last 100 years because of climate change. Globally, the Earth’s average surface temperature has increased by 0.6 ± 0.2°C in the twentieth century, and this trend is expected to persist with a total rise of 1.4 to 5.8°C by 2100. However, the temperature rise in SSA is estimated to be roughly +2.0 to +4.5°C by 2100, and this is expected to be stronger than the global average. The average is expected to be higher in SSA then globally because most of SSA lies in tropical and subtropical latitudes, where temperatures are high throughout the year and vary more from daytime to night time than during the course of the year. Although these trends appear to be widespread over the continent, the temperature changes vary considerably between regions and countries (Kotir). These higher temperatures lead to a hotter drier climate, which leads to water stress of crops and decreased crop yields. There is predicted to be a more than 15% decrease in the average production of maize, sorghum, and millet by mid century because of future changes in precipitation and temperature. With only 1 °C of warming, yields would be reduced by approximately 65% of the present day area for maize harvest in the region. The average decline in maize yield is projected to be as high as 30% in many parts of SSA (Ahmed).  According to Nkulumo Zinyengere, by 2050, crop yield losses could reach up to 50% in come countries in SSA. Since rain fed farming is 97% of agricultural production when there is less rain and no irrigation systems to water the crops, yields majorly suffer. 

The region’s reliability on rain is problematic in terms of how the region will adapt to climate change. Current records indicate that rainfall patterns across Africa vary extremely, while some regions are predicted to have more long term wetting, such as East Africa, others such as South-East Africa displays a relatively stable regime, while the Sahel exhibits more recent drying. The Western Sahel saw a pattern of decreasing rainfall since the late 1960s, 20 to 40% between the periods 1931–1960 and 1968–1997. One-third of the people in Africa reside in drought-prone areas and are vulnerable to its consequences. In the 1990s and 2000s, a number of East African countries suffered severe droughts as a result of failed annual rains. With the severe droughts, crops were unable to grow and many people were left without food to eat. The 2000/2001 and 2006 droughts were the worst in at least 60 years in Kenya affecting more than 3.5 million people. However, some countries in SSA have had too much rainfall. For example, Burkina Faso (2007 and 2009), Mozambique (2000 and 2001), Ethiopia (2006) and Ghana (2007 and 2010) have experienced severe flooding with harsh livelihood consequences. The severe droughts and flooding is expected to worsen with climate change, both negatively affecting agriculture throughout Africa, the continent is expected to have lost on average 4.1% of its cropland by 2039, and 18.4% by the end of the century (Kotir). Future warming will be responsible for a net decrease in cereal crop yield across the region, and the productivity of some crops will be deceased by the drought resulting from the reduction in growing season precipitation (Ahmed). Without adaptation, total food production would fall by 1.6%, with a heavy loss of 10.6% of sugarcane, and 24.1% in wheat. In this case, the number of malnourished children would have increased by almost 2 million. The number of malnourished children is projected at 32 million in 2050, compared to about 30 million in 2000 (Calzadilla). This is a shockingly high and an unacceptable total number that the region can work towards decreasing with or without using adaptations to climate change.With these many negative effects, SSA is going to suffer and lose a lot more agriculture and their livelihoods if changes are not implemented in their agricultural practice in order to adapt. 

Adaptations:

Improved irrigation and expanded crop area:

Some major agricultural adaptations to climate change are improved irrigation systems and enhanced productivity. The lack of irrigation systems is an example of slow technological change in the area. Since only 4% of the total crop area is irrigated, compared with 39% in South Asia, there is much room for expansion. By applying supplemental irrigation to 15.2 million ha in SSA, there is a potential for reaching more than 30 million rural poor. Supplemental irrigation can provide about 100 mm of water during crucial dry spells, which can double rainfed cereal yields from about 1 to 2 Mg ha-1(Kotir). This shows promising results as an adaptation technique. Irrigation is one of the technological advances that has been able to advance agriculture to a great degree worldwide, as well as reducing poverty in multiple ways. One of these includes new employment opportunities on irrigated farms or higher wages on rainfed farms, which will lead to lower food prices as irrigation enables farmers to obtain more output per unit of input. Another way is that gains in agricultural productivity through irrigation can stimulate national and international markets, improving economic growth (Calzadilla). The problem with supplemental irrigation is that it is often expensive to buy and maintain, and many poor farmers cannot afford the initial investment. This may be part of the reason why the percentage of irrigated crop area is so low.  

In the study by Calzadilla, two different possible adaptation scenarios to climate change in SSA are investigated. The first doubles the irrigated area by 2050 but keeps the total number of crops constant. The second scenario keeps the irrigated area constant but doubles the total crop area. The efficacy of the scenarios as adaptation measures to cope with climate change is measured by changes in regional GDP. Both scenarios enable farmers to achieve higher yields and revenues from crop production, the first scenario increases regional welfare by US$119 million, but the second scenario reaches US$15.43 billion. This is at least in part because of the relatively low share of irrigated area in a total agricultural area in SSA, doubling irrigated area or even increasing it further does not offset the GDP losses caused by climate change. Not only is expanding the total crop area more beneficial for GDP, but it is more beneficial for child malnutrition as well. Under the first scenario, the number of malnourished children declines by only 0.3 million children. In contrast, the second scenario leads to a decline in the number of 1.6 million malnourished children. Therefore, improving crop yields in both rainfed and irrigated areas is a strategy that would almost completely offset the yearly impact of climate change on child malnutrition (Calzadilla). From these statistics, it is clear how increasing total crop area is a more effective adaptive measure in terms of decreasing child malnutrition and poverty, as well as increasing GDP, than implementing more irrigation systems. While on a large scale it may not be entirely possible to double the entire amount of crop area, for each individual small scale farm it may be more beneficial to increase their crop area rather then invest in irrigation. The problem with irrigation however, is that if the region is in a drought and there is no water anywhere, it may not be possible or at least be very expensive to find water to irrigate crops with. Therefore this adaptation is not always effective. An issue with increasing crop area as well is that when there is a drought and none of the crops a specific farm raises survives because of where they are located in the region, increasing crop area would not be able to effectively increase yields. This strategy would only be effective when a partial drought decreases the majority of yields but does not totally kill the crop.

Increased irrigation efficiency:

While implementing new irrigation systems may not always be possible for every farmer, improving irrigation efficiency in rainfed agriculture may be more realistic and also help to release the pressure on the regional water sources. Because of the lack of affordable technology, and due to the limited initial irrigated area in the region, an increase in agricultural productivity achieves better outcomes than an expansion of the irrigated area, increasing both rainfed and irrigated crop yields by 25% for all SSA countries. In order to improve the efficiency of irrigation through better-designed irrigation projects and the large untapped water resources, more opportunities need to be generated to invest in irrigation. In order to accomplish this, new investments in roads, extension services, and access to markets need to be made. The effectiveness of irrigation and agricultural productivity may also reduce poverty and promote economic growth. Improvements in agricultural productivity can provide a pathway out of poverty for rural households in several ways. There are poor households that own land who benefit from improvements in crop and livestock yields through greater output and high incomes. Households that do not own land but provide farm labor, who benefit from higher demand for farm labor and wages. Then there are households that do not own land or provide farm labor, who would benefit from a greater supply of agricultural products and lower food prices. Non-agricultural rural households and urban households may also benefit from improvements in agricultural productivity through a greater demand for food and other products. (Calzadilla). The measurement of how effective an adaptation is is through providing a pathway out of poverty is maybe a more directly helpful one to the people in the country than a measurement of GDP. 

Improve rainwater harvesting and management techniques:

While irrigation is an important adaptation when there is a lack of rain in the region, another important adaptation is rainwater harvesting and management, since even when there is rain, much of it gets wasted and is not effectively used towards crops. According to Birhanu Biazin, in SSA less than 15% of terrestrial precipitation takes the form of productive green transpiration. This means that only this limited amount of rainfall can actually be used by the crops. The rest of this rainfall is wasted, 50% by soil evaporation, as much as 10-30% by surface runoff, and depending on the rainfall pattern 10-30% from drainage. Not only that, but with a 2 C climate warming, there will be a 10% reduction in precipitation and a 150-200% decrease in water resources possible for regions located in arid climate zones. Because of these factors, in order to decrease the amount of wasted water, another useful adaptation is rainwater harvesting and management (RWHM) techniques, which have a significant potential for improving and sustaining the rainfed agriculture in the region. There is a wide variety of micro catchment, macro catchment, and in situ RWHM techniques available in SSA developed by researchers. It has been shown in studies that micro-catchment and in situ RWHM techniques could improve the soil water content in the rooting zone by up to 30%, hence substantially reducing non-productive losses (Biazin). 

Though macro-catchment rainwater harvesting systems may be beyond the capacity of the poor because of the initial investment, in the long term there would be substantial net profits compared with the meager profits or losses from the existing smallholder based farming systems. Micro-catchment rainwater harvesting systems are designed to collect runoff from a relatively small catchment area within the farm boundary. The runoff water is usually then guided into a type of infiltration enhancement structure and used to grow plants, and the catchment area can be easily controlled by the farmer which makes the systems easy to adapt and replicate. Some of these techniques use things such as trenches and terraces made out of different materials to trap the water. Indigenous peoples use different and unique methods for their specific crops and land. Most smallholder farmers are indigenous people who have their own culture or specific way of doing things. The macro-catchment rainwater harvesting systems usually consists of the rainwater collection catchment, the storage structure, and the target areas. In this system, the runoff is usually collected from external catchments and diverted into well designed storage structures. This water is then used for either supplemental irrigation during dry-spells or for domestic consumption. The most common macro-catchment RWHT techniques in SSA include open ponds, cisterns, micro dams, sand dams, and spade-irrigation systems. Many of these widely applied methods are indigenous or modified from indegenous practices. In situ rainwater harvesting includes techniques for enhancing infiltration, reducing runoff and evaporation or for improving soil moisture storage in the crop rooting zone. These techniques are aimed at enhancing rainfall infiltration and reducing soil evaporation. The central idea is to turn blue water into green water to reduce direct soil evaporation, therefore causing it to be transpired by plants. Doing this requires appropriate land and crop management systems. There are two management periods to maximize the use of precipitation for dryland crop production: the first period of rain storage, which lasts from the harvesting of the previous crop until the planting of the next crop; and the second period, lasting from planting until harvesting of the crop (Biazin). RWHM techniques have a significant potential for improving and sustaining rainfed agriculture in the region. The indigenous RWHM practices are more common and widely accepted by smallholder farmers than the introduced ones (Biazin). Each different local area faces different challenges when it comes to climate change, and each must choose to tackle the changes differently depending on the resources available to them. Based on a review of the various indigenous soil and water conservation systems in SSA, it is recommended that development projects need to incorporate indigenous practices into recommended resource conservation techniques (Biazin). This is why localized adaptation techniques are practiced more than generalized techniques to increase crop yields. Each farmholder must decide for themselves what is best for them and their crop based off of available information, research, and resources. While there is often not easy access to information in SSA, recently there has been an effort made to distribute cell phones to make information more accessible. It would be best if every farmer had access to the information or research that is being done on how to adapt to these changes. It is recommended to have more integrated efforts to develop the indigenous practices and to modify the introduced RWHM techniques in accordance with existing socioeconomic and biophysical settings (Biazin). The focus on indigenous practices ties in nicely with the large amount of small scale agriculture in the region.

Tailor adaptations to small scale farmers:

While there are many different generalized adaptations for regions of Sub-Saharan Africa, not all adaptations are relevant in every area. There are more specific adaptations for unique areas that should be applied on a local scale rather than the regional scale depending on the effects of climate change. Since close to 70% of the population depends on small scale agriculture, it is more important to focus on adaptations for small scale farms then larger scale (Zinyengere). Climate change impact assessments on agriculture in Southern Africa mostly carried out at large spatial scales, which risks missing out on local impacts and adaptation potentials that reflect the range of unique biophysical and agronomic conditions under which farmers in the region operate. This large scale assessment leads to generalized and broad conclusions and recommendations of adaptation strategies over large areas, which are not reflective of impacts at the farm or community level and may not speak to local smallholder farmers. These types of studies may be useful for national and regional planning, but run the risk of missing out on local peculiarities where impacts vary considerably. These farmers operate under unique conditions and practices that often emanate from personal and community experience, culture, financial and physical resources, and vary over short spatial scales (Zinyengere). These factors make it clear that focusing on adaptations for small scale farmers will be more effective.

Genetically improve crops for increased productivity:

Another critical adaptation that will enhance agricultural productivity in SSA is genetic improvement of crops. Genetic improvement, as well as appropriate agronomic management techniques as described above, are vital to increasing agricultural productivity (Biazin). Genetic improvement includes diverse techniques such as breeding different varieties, altering genes, or transferring genes between species to accomplish a desired result, drought tolerance which will increase farmers’ yields. Although water is often the principal constraint for agricultural productivity, investment in research and development are also necessary. Observed yields are less than one-third of the maximum attainable yields, and therefore the potential for productivity enhancement is large, particularly for maize, sorghum, and millet (Calzadilla). Genetic approaches to increasing the water productivity of crops encompasses four traits of plants; traits that reduce the non-transpiration uses of water in agriculture, traits that reduce the transpiration of water without affecting productivity, traits that increase production without increasing transpiration and traits that enhance tolerance of water stress. Some genetic improvements made to crops include those that mature early, require less water, or produce higher yields. Some of these early-maturing cultivars can escape droughts and provide yield even during years with below average precipitation (Biazin). In SSA, there is research and development towards engineering drought tolerant and yield boosting varieties such as wheat. According to Lawton Nalley, wheat is the second most consumed grain crop and is a staple food for the majority of the population living in semi-rural and urban areas. The role of public wheat breeding is to reduce food insecurity in South Africa. More agricultural research is needed specifically in plant breeding to increase yields and help mitigate food insecurity. In order to foster scientific innovation for food security, the South African government funds the Agricultural Research Council (ARC), which conducts research on wheat as well as other crops. The ARC has worked to develop genetically enhanced wheat varieties to produce higher yields. South African farmers who adopted their wheat varieties experienced an annual yield gain of 0.75%, 0.30%, and 0.093% in winter, facultative, and irrigated spring wheat types, respectively. Using these ARC varieties, wheat producers gained $106.45 million (2016 USD) during 1992-2015. Every dollar invested in the ARC wheat breeding program generated a return of approximately $5.10. These gains are very positive and show a very bright future for the use of genetically improved crops. These public breeding programs such as ARC, must continue agricultural research to meet the growing food demand, decrease present global food insecurity, and maintain the genetic enhancements that directly enhances yield and benefits low income consumers. 

There is a widespread consensus that agricultural research and development are pivotal to economic progress in SSA’s overall growth. In order to feed the growing global population, total wheat output would need to increase by 38%, or 0.86% annually to meet the estimated demand in 2050 via increased areas planted or genetic gains. From 1870 to 2010 global wheat yield potential was rising only 0.61% annually, and is still not on track to meet the estimated demand by 2050 with current agricultural strategies and crop yields. However, by using some of the ARCs genetically enhanced winter strains with an annual yield gain of 0.75%, there is a little more hope to get closer to meeting the estimated demand. In order to secure food supplies, it is essential for the current low rates of progress in yield potential of wheat to be accelerated. Out of all major food crops, wheat has shown the lowest rate of progress in yield potential despite its growth in demand as a food crop. The role of public wheat breeding in reducing food insecurity in South Africa climate change requires integrated approaches cross plant breeding, economic, agronomic, soil, biologic, hydrologic, and other scientific disciplines. Feeding a growing population will need to be met with both increased domestic supply supplemented with global imports. Increasing domestic supply through public and private wheat breeding, extension services, and scientific agricultural research will help shield south africa from an uncertain global grain market and risk from exchange rate fluctuations. Continued funding for public plant breeding programs ensures that genetic gains accomplished by wheat breeders globally avoid plateauing, which is a potent tool for combating global food insecurity. Food security cannot flow from plant breeding alone, and payoff from the investment in enhanced breeding is one piece of the puzzle of achieving food security (Nalley). While the widespread use of genetically improved crops would greatly increase yields, not all small scale farmers have access or even information about these crops. However, if there is widespread education about these crops, there is a better chance that they will be better understood and used, greatly increasing the amount of crop yields and decreasing the threat of food security.

Conclusion:

A combination techniques need to be made in order to adapt to the effects of climate change on agriculture in Sub-Saharan Africa. Since such a large portion of agriculture in SSA depends on rainfed crops and are farmed by small scale agriculture, which are more likely to use indeginous practice then new more generalized practices, big sweeping adaptations to climate need to be modified and adapted to each unique farm, region, and culture. Depending on each individual farm’s available resources, different adaptations are possible. Some adaptations that should be used if a farm has every resource available to them would be to increase crop area, increase irrigation area, increase irrigation productivity, use rainwater and harvesting management techniques, and use genetically improved crops.When there is a lack of rain and the climate gets drier, shifting to genetically improved  crops may be the most profitable direction to take. However, for farmers to make a decision on which forms of adaptations will be the most effective for them, they first need to be educated on what kinds of adaptations there are and then have the means to obtain some of the needed resources.They may need money or programs to help them get to the point where they can make these changes to their agriculture. There are programs run by the UN, such as The Food and Agriculture Organization (FAO), which is a specialized agency that leads international efforts to defeat hunger. The South African government also funds the Agricultural Research Council (ARC), to research crop improvements. There are a variety of other programs designed to help with many different issues occuring in SSA.

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