Prospect of Sub-Saharan African Agriculture Amid Climate Change: A Review of Relevant Literatures

Sub-Saharan Africa is an important world region in terms of food and feed production. However, climate change is becoming more and more serious threat to agricultural production in the region. Various and relevant literatures were contacted aimed at finding the impacts, causes and possible solution to the threat of climate change in Sub-Saharan Africa. Declining agricultural productivity and farm incomes, occurrence of extreme weather conditions, soil degradation and proliferation of pests and diseases were some of the impacts of the Change. Deforestation, transportation, power generation, burning of fuel, poverty and agricultural practices were among the causes of climate change in the region. Poverty alleviation, adequate mitigation and adaptation campaigns, afforestation and incorporation of climate change into long-term developmental programs were some of the possible ways of dealing with climate change threat in the region. It is recommended that apart from provision of alternative sources of fuel, governments should also create job opportunities in the region as well as ensuring that fallen trees are replaced.


Introduction
Climate change is an evitable phenomenon, which is occurring in every part of the world. It affects people, plants, animals and otherthings in various ways. There is an escalating consensus among scientists that the earth is warming due to anthropometrically increases in greenhouse gas (FAO, 2009;Asfaw & Lipper, 2011). Sub-Saharan Africa (SSA) is an important world region in terms of crops and live stock production. Various agricultural commodities are produced in the region for consumption and exportation to different parts of the world, which are used as food and feed, as well as raw materials to numerous industries for processing into different types of finished products for human use. However, climate change turns to be a critical challenge militating against such important contribution the region is offering to the world. It is noted that its negative effects are threatening to reverse the developmental gains in many parts of the world, especially SSA where the overall impact of the change has been negative (Dube & Phiri, 2013). The change brings about unpredictable and variable rainfall both in amount and timing, changing seasonal patterns and an escalating frequency of adverse weather events such drought,cyclone,flood, soil erosion and so on.
Based on Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), warming in Sub-Saharan Africa (SSA) is expected to be greater than the global average, rainfall is projected to decline in certain areas and there will be reduction inthe production for a range of cereal crops (Ringler, Cai, Koo and Wang, 2011). Experts predicted that climate change will make dry areas to become drier and wet areas wetter across West and Central Africa, which will bring about longer and more frequent dry periods as well as an increase in temperature which is likely to encourage proliferation of pests that are threat to staple crops (IFAD, 2011). Thus, there is strong warning that climate change is a critical threat to food security in the region.
Therefore, it is important to glance back and found out the various effects of climate change on agriculture, especially in SSA as revealed by various studies. This will further give light to researchers, policy makers, donor agencies, governments as well as the farmers to further realizethe significance of climate change effects and implications in order to take appropriate measures to tacklethe menace of theChange at this point in timeso as to check or at least suppressed its future effects. The study tried to answer the following questions

Methodology
Sub-Saharan AfricaSub-Saharan Africa:SSA is aregion of the Africancontinent south of the Sahara Desert, consisting of 42 African countries ( Figure 1 revealed their names)situated on the Sub-Saharan African mainland, in addition to six island nations-Madagascar, Seychelles, Comoros, Cape Verde and São Tomé and Príncipe. The north andsub-Saharan regions (whichare distinct culturally as well as geographically) of Africa were separated by the extremely harsh climate of the Sahara, forming a barrier interrupted by the Nile River (New World Encyclopedia, 2015). "The modern term sub-Saharan corresponds with the standard representation of north as above and south as below. Tropical Africa and Equatorial Africa are alternative modern labels, used for the distinctive ecology of the region" (New World Encyclopedia, 2015, p.3).
The climate of the region is influenced largely by distance from the equator and altitude, whereby in the highlands, it can be temperate even close to the equator. Although precipitation is steadier in the humid forests, rainy and dry seasonsalternate. Rocks that solidified during the early cycles of eruptions on Earth are the greatest source of economically important metals, particularly gold and diamonds. The great age of sub-Saharan Africa's rocks has made the region well endowed with these and other metals, including copper and chromium (New World Encyclopedia, 2015).
Generally, SSA is the world poorest region, still suffering from the legacies of colonialism, slavery, native corruption and other vices. Many governments face difficulties in implementing policies aimed at mitigating the effects of the harsh situations (New World Encyclopedia, 2015).
The study reviewed relevant and reliable literatures such as that of FAO, 1GPCC, World Bank, WHO, UNFCCC, IFAD and other important ones.

Climate Change and Agriculture
Climate change can be define as a change in weather patterns due to human activities (industrial, domestic and agricultural) and earth's natural processes (such as variations in solar radiation received by Earth, volcanic eruptions, etc.) over a long period of time. In other words, "Climate change means a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods" (United Nations Framework Convention on Climate Change, 2014, par. 2). Climate is the primary determinant of agricultural productivity, and thus,base on the vital role of agriculture in human welfare, there was concerned regarding the potential effects of climate change on agricultural productivity, because climate change is expected to influence crop and livestock production, hydrologic balances, input supplies and other components of agricultural systems and the nature of these biophysical effects and the human responses to them are complex and uncertain. For example, crop and livestock yields are directly affected by changes in climatic factors such as temperature and precipitation and the frequency and severity of extreme events like droughts, floods, and wind storms (Adams, Hurd, Lenhart & Leary, 1998).
Climate change and agriculture are interrelated processeswhereas global warming is expected to have significant impacts on conditions affecting agriculture, agriculture has been shown to produce significant effects on climate change through the production and release of GHGs such as CO 2 , CH 4 , and N 2 O (Wikipedia, 2014). It is reported that agriculture contributed 13% of total GHG emissions in the year 2000, and it is alarming that in developing countries, such emissions are projected to rise in the next decades owing to population and income growth, among other factors, and within the agricultural sector, fertilizer application, livestock and manure management, rice cultivation, and savanna burning are the main sources of emissions (Rosegrant, Ewing, Yohe, Burton, Huq & Valmonte-Santos, 2008).
The socio-economic impacts of climate change implications are already visible, especially in Africa and the world at large. The most alarming effects is the intensity and frequency of extreme weather events like droughts, floods and heat waves, which have already started to create innumerable disaster for economic activities and livelihood sources derived from natural resource base of the countries, especially in Africa(Dube&Phiri, 2013). In West Africa, on average, temperatures have been rising faster than the overall rate of global warming and this will affect agriculture and could lead to flooding and erosion of low lying areas, with negative consequences for crop and livestock production and for the rural communities that depend on agriculture for their livelihoods (IFAD, 2011). Rosegrant et al. (2008) reported that global agriculture will be under serious pressure to meet the demands of growing populations using finite, often degraded soil and water resources that are predicted to be further stressed by the impact of the change. Vermeulen (2014) stated that, "Tropical crops, livestock and fisheries are most affected by current climate change; regions of major exposure to climate change coincide with high prevalence of poverty and food insecurity". He explained that its negative impacts on crop yields and fisheries are more serious in tropical regions with possibility of livestock in the regions having a greater risk of climate change owing to their sensitivity to temperature, water and feed availability. According Adamset al. (1998), climate change may also change the types, frequencies and intensities of various crop and livestock pests; the availability and timing of irrigation water supplies; and the severity of soil erosion.
Source: World Map, 2011 Despite the fact that the climate has so many adverse effects on agriculture, studies have shown that it has certain benefits to agricultural production. For instance, Rosegrant et al. (2008) confirmed that, CO 2 levels have a positive growth response for some staplecrops under controlled conditions known as the carbon "fertilization effect". Adamet al. (1998) reported that CO 2 is essential for plant production because, its rising concentrations have the potential to enhance the productivity of agro-ecosystems.

Impacts of Climate Change on Sub-Saharan African Agriculture
Climate change has many effects on the productivity and farm income of farmers. Scientists have warned that SSA is vulnerable to the threat of climate change because 95% of its crop production relies totally on rainfall (SciDev. Net, 2016). Agriculture sector of the region is likely to experienceperiods of prolonged droughts and/or floods. Arid and semi aridland could expand in by 60-80m/ha. So also changesin sea temperatureswill affect fisheries productivityby 50-60%, and according to World Bank forecast SSA will exceed Asia as the most food insecure region having 40-50% of global malnourished people in 2080 compared with 24% today, and by 2080, 9-20% of arable land will be less suitable for agriculture (Isingoma, 2009). Due to variations in temperature and precipitation, crop pests and diseases in addition to altered soil fertility in Africa are predicted to increase leading declining farm incomes and rising unemployment (FAO, 2009).
The impactsof drought (cause by climate change) on the energy sector have been felt through losses in hydro-power potential for electricitygeneration and increased runoff, which led to siltation thereby retardingthe generating capacity (Isingoma, 2009). Table 1 shows the effects of the changes of various climatic elements in different countries and regions of SSA, which have serious consequences on food security in the region. As can be seen from the Table, all countries in SSA experienced increase in temperature which led to increase evapo-transpiration thereby leading to decline in soil moisture, which in turn results in the destruction of arable and permanent crops in the region. It can also be seen from the Table that changes in rainfall patterns and amount as well as occurrence of flood and drought had significant effects on the both the quality and quantity of agricultural products in the region. These are serious warnings about the negative effects of climate change on the food security of the region, which need urgent and appropriate measures to be taken by citizens and various governments of the region, Non-Governmental Organizations, donor agencies as well as international bodies. It was projected that cereal production for a range of crops in SSA will decline by a net 3. Even though, they face a world where climate change will increasingly threaten the food supplies, the less privilege in coastal cities and low-lying islands of SSA are among the most vulnerable to climate change in the world, as well as the least able to adapt to the change (World Bank, 2013).

Causes of Climate Change in Sub-Saharan Africa
Studieshave shown thatthere areso many factors that lead to climate change in SSA. Stern (2006) reported that there is strong scientific evidence that human activity is causing global warming, GHGs being the main sources. He explained that in order of global importance are electricity generation, land-use changes (particularly deforestation), agriculture and transport, and the fastest growing sources are transport and electricity. According to Rosegrant et al. (2008), climate change results from the concentration of GHGs such as CO 2 , nitrous oxide (N 2 O), and methane (CH 4 ) as well as emissions from agriculture which comes from four principal subsectors: Agricultural soils, livestock and manure management, rice cultivation, the burning of agricultural residues and savanna for land clearing,among which N 2 O is the largest source of GHG emissions, accounting for 38% of the global total, which is produced naturally in soils through the processes of nitrification and denitrification.
Even though some have argued that climate change is actually caused by natural occurrences, the Earth's average surface temperatures have risen by 0.4°C since 1970s, which is an irregular increase that is extremely difficult to explain by natural causes and thus, certain changes do occur in the sun's activity, volcanic eruptions, and other natural events which all contribute to changes in the earth's temperatures, but only an increase in GHGs can explain the abnormal increases. Therefore, human activities that result in the release of these greenhouse gases well beyond natural levels include things like deforestation, burning of fossil fuels, changes in wetland construction, and so forth (Ecolife, 2011). Some of the anthropogenic causes of climate change in Sub-Saharan Afirca include the following: (a) Agriculture: Sub-Saharan Afirca cannot do without agriculture because it is one of the important occupations of the people in the region-ranging from crop and livestock production to processing and marketing of different agricultural commodities. However, in the course of carrying out their activities, Sub-Saharan African farmers engage in some farm practices such as bush burning, clean clearing, overgrazing, same cropping,etc., whichexacerbate global warming.  Deforestation causes lost of species and soil degradationwhich are important form of environmental degradation. Unfortunately, sub saharan Africansdepend on subsistence farming as their means of livelihood and thus clear forests so as to expand their farms for feeding their growing population (Cunningham, 2010). From Figure 1 above, it could be seen that people in SSA rely on wood as a source of fuel for cooKing and similar activities, leading to indiscriminate felling of trees. The fact is that majority of the people cannot afford to use kerosene for all their cooking activities talk less of natural gas, due to high cost couple with unavailability of the commodities. In Nigeria (the highest oil exporting country in the region) for instance, the price of kerosene at black market usually more than triple the official price and it is on rare cases that one can get it at official price even after wasting lots of energy and time. Thus, people were left with no alternative except to be felling trees for various domestic purposes.
(c) Transport: It was reported that Africa's emissions from the transport sector have grown 50% since 1990 -2nd fastestgrowing source of emissions in the world after Asia. This will increase health effects and climate change impacts (UNEP, 2013). Thus, urban air pollution is escalating in SSA, mainly causedby use of fossil fuels in transport;yet, vehicle emission standards are insufficient and inadequately enforced. Only eight countries in the region have operational routine air quality monitoring systems. Traffic congestion is of growing concern in many cities. The causes include ineffective public transport;lack of transport demand measures; poor quality of cycling and walking infrastructure; lack of integratedland-use policies, and poor road discipline (Stockholm Environment Institute, 2013). SEI revealed thatno country in SSA has diesel sulphur content less than 50 parts per million, several have between 2,000 and 5,000 ppm of such content or even more, only five countries have emission standards for vehicles,and only eight have set air quality. SEI lamented that SSA countries have many old vehicles lacking emissions control,poor vehicle maintenance, and a lack of cleaner fuels as well as inadequate regulatory frameworks specific to vehicle emissions coupled withinappropriate monitoring equipment,and existing laws and regulations are inadequately enforced.

Possible Ways of Combating Climate Change in Sub-Saharan African
Conducting Adaptation and mitigation workshops, seminars, and panel discussions on climate change are efficient ways of dealing with the acute temperature and rainfall variability which leads to decline in agricultural yield, water scarcity, drought and flooding, occurrence of various diseases and increase in deforestation. Key stakeholders, public and private officials, university academicians and researchers as well as personnel from different sectors; should be participate (World Bank, 2015). This will pave ways in enlightening people and governments about the danger of some practices that cause climate change in SSA and how the practices can be checked adequately and appropriately. It was reported that it was the inability of SSA governments to treat climate change into long-term investment and planning risks that leave countries across the region vulnerable to droughts, floods, heatwaves and rising sea-levels (The Guardian, 2016).
There are various strategies that can be employ in response to climate change so as to retard its escalating nature in such a way to cope with its impacts to some extents, the process of adopting these strategies is known as mitigation. According to Wikipedia (2014), climate change mitigations are actions to limit the magnitude and/or rate of long-term climate change and it is generally involves reductions in human (anthropogenic) emissions of GHGs, which may be achieved by increasing the capacity of carbon sinks, such as through afforestation. The Wikipedia pointed out that mitigation policies can greatly reduce the dangers associated with human-induced global warming. It however argued that effective climate change mitigation will not be achieved if each agent (individual, institution or country) acts independently in its own selfish interest. Therefore, there is the need for SSA countries to join hands to address the problems of climate change. Itis paramount to seek waysof improving productivity, via access to improved seeds, fertilizers, water management techniques, equipment, financing, and markets because, it is noted that only about 5% of Nigerian smallholders use improved seeds due to its availability, quality and pricing, whereas fertilizer application rate is approximately 7 kg per hectare, which is a small fraction of the global average of 100 kg/ha, and only 18% of farmers receive extension services (Nwuneli, 2011). Rosegrant et al. (2008) stated that, "Even with sufficient mitigation measures the current scientific consensus holds that GHG emissions and atmospheric concentrations are set to increase for some decades. Consequently, global mean surface temperature will continue to rise long after an emissions peak has passed". Thus, in this context scientists should be encourage to conduct research to come up with improve varieties of crops and breeds of animals that can resist adverse effects of climate change such as insufficient rainfall, high temperature, strong wind and so on. Such varieties and breeds should continuously be upgraded and made available to the farmers at affordable price or even free of charge. Adequate extension activities should be carried out in every nooks and corners of SSA to enlighten famers about the existence and technical knowhow of the varieties and breeds for possible utilization by the farmers of the region.
It is suggested that there is a very strong connection between deforestation and poverty and thus argued which causes the other. Whatever the case may be both are very important related problems that need to be addressed (Cunningham, 2010). Governments in SSA need to provide their citizens with alternative sources of fuel at affordable prices so that people can be restricted from indiscriminate felling of trees for firewood and other purposes. Without such alternatives no matter how much effort such governments put to stop the people from such acts, will be in vain. There is also need for SSA governments to device ways of improving the welfare of their citizens such as creation of jobs opportunities, provision of social amenities, etc., as well as awareness campaign about the danger of deforestation. Cunningham also explained thatTargeting and fixing poverty are considered to be conventional ways to deal with deforestation and thus, governments together with various organizations, sees development as the main key to solution of the problem. Nonetheless, industrialization is also one of the causes of deforestation. This never ending circle of frustration leave many people wondering if there solution to the problem of deforestation, apart from letting the nature and the economy to deal with it. He pointed out thatplanting trees to replace the fallen ones and establishing orchardmay help greatly.
To avoid climate change disaster, it isnecessary to reduce the GHGs emission of our modern energy systems, which haveadverse impacton our planetary boundaries (The Guardian, 2016). Here SSA leaders should collaborate with the rest of the world leaders to tackle the problems of GHGs emission from modern energy sources such as electricity generation. Because, Sub-Saharan Africa is still facing some of the earliest, most severe and most damaging effects of climate change. Thus, Africa's leaders need to support international efforts to address climate change. But they have to immediately deal with the alarming reality behind Africa's struggling and insufficient modern energy (The Guardian, 2016).
African countries are busy investing in long-lived investments such as ports, large dams, and social infrastructure, such as hospitals and schools which will probable last beyond 2050. But by then, Africa's climate may seriously change from what it is today. For instance, the Overseas Development Institute (ODI) and Climate and Development Knowledge Network (CDKN), revealed that governments and businesses across SSA are not considering long-term climate data in their investments and planning decisions. This includes studies from Zambia, Malawi, Rwanda, Ghana and Mozambique. It is alarming that poor use of climate data could put societies into conditions that make them very vulnerable to droughts, floods, high temperatures or sea-level rise in the future. Thus, putting climate change into long-term investments and planning decisions is vital for supporting climate-resilient development, but it's not happeningin SSA (The Guardian, 2016). Therefore, SSA leaders should be considering climate change in their long-term investments and planning decisions so that its impacts can be suppressed at the long-run.
Perhaps, the preliminary point is to enhance the quality and quantity of African climate observation networks and scientific capacity in SSA. This will not only help in establishing information about past and current climates, as well as 'ground-truth' climate science through generating domestic knowledge, perspectives and skill butwill also serve as a link between scientists, policy-makers and practitioners and help with presenting climate information in a format that decision-makers can act upon(The Guardian, 2016).
Generally there is little impact of agriculturalresearch across SSA on improving the living standard of wet season farmers underthe existingclimaticconditions. Thus, a comprehensive strategy is needed if the challengeof adapting agriculture tofutureclimate change is to bear fruit. It is useful to consider the criteria by which current successful initiatives should be judged. Success will be measured by the way that farmers are better able to cope with climate-induced risk and adapt tofuture climate change. But for that tohappen and for agricultural research to have made a considerable contribution, in the shorterterm there are key 'foundation stones' that must be in place upon which such research mustbe built (Cooper, Stern, Noguer and Gathenya, 2013).
Climate change adaptation and mitigations are essential instruments to save the life of the vulnerable communities particularly in African continent. Integration of adaptation measures into sustainable development strategies is an efficient way of tackling climate change impacts. This will help to reduce the pressure on natural resources. After adequateenvironmental education and awareness campaign, stakeholders should do their best to bring change through adaptation and mitigation options. Through adaptation and mitigation workshops, the attitudes of peoples towards climate change solutionswill be changed (World Bank, 2015).
A key factor to implement is to encourage the community to participate in all adaptation and mitigation plan. In general, to minimize the impacts of climate change on Africa all governmental and non-governmental organizations, private sectors and individuals should participate in afforestation, re-afforestation and forest conservation, and there should be concern from all organizations(private and individual) for water and soil conservation as well as wise use of water. The culture of water harvesting and storage techniques, livelihood diversifications and enhancing the use of climate resilient green economy are vital practices (World Bank, 2015). Conducting research on climate change and dissemination of the finding to decision makers and stakeholders is another way of minimizing the impacts of climate change. Therefore, educational institutions, research centers and meteorological organization should focus on climate change researches. The data for such researches should be made available to researchers free of charge in order encourage such researches and publication of the findings. The people of Africa should be educated and made aware of their role and how they can deliver such role in climate change adaptation and mitigations. It is noted that any governmental plan without the recognition of the people is difficult to implement and be unsuccessful. (Gemeda and Sima, 2015).
Increase in Population worldwide, increase food demand, thus there is need for higher crop yields, leading to more intensive land use, which in turn result in nutrientsdepletion and soils degradation. Such nutrients depletion can only be immediately reversed with the help of chemical fertilizers thus, fertilizer usetrends can act as a useful investment in agriculture. However, it is noted that Average rates offertilizer use have risen ten times, that is from 5 to 50 kg/ha in many parts of Asia and LatinAmerica during the last 50 years whereas in SSA they remain atabout 5 kg/ha from 1980 onwards as can be seen in figure 4 (Cooper, Stern, Noguer and Gathenya, 2013).
Therefore, SSA governments should try as much as possible to ensure adequate supply of fertilizers to every parts of the region at prices that are affordable to farmers. When this happened, the farmers could able to produce more food to meet the demand of the escalating population of the region.  Considering that the vast majority of actions on climate change are funded by developedcountries, the slow release of funding for adaptation projects is a significant cause for alarm. Regrettably, the principle of common but differentiated responsibilities and respective capabilities has not been consistently applied in relation tofunding for climate change programmes in Africa (FAO, 2009). The FAO explained that the window of opportunity for investment in agricultureis restrained due to the potential impact of climate change inminimizing viable options for rural development. For exampleinvestment in productivity can be optimized in conditions wherenatural and labour resources are undamaged by the disruption tocrop cycles caused by climate change. This would meangovernments and key stakeholders would be required to accelerate their efforts on expandingproduction capacity to maximize results. Thus, strategies for agriculturalintensification and resilience of food production systems should be fortified through thecreation of key synergies between mitigation and food security.
Renewable energy is an ideal option to complementlarge-scale hydro-power generation. Geothermal, smallhydro, biomass cogeneration and wind energy optionsare attractive since the resources are widely availableacross the continent. These renewable energy options arenot only environmentally friendly, but are more suitableadaptation responses to the adverse impacts of climatechange (Ibingom, 2009).

Conclusion
Climate change has been causing a lot of problems to agriculture in Sub-Saharan Africa leadingto decline in productivity due extreme weather conditions such as high temperature, drought, flood, cyclones, etc. This gives an important signal about food security in the region. It was found that climate change and agriculture are inter-relatedcausing significant effects on each other.
Deforestation, agricultural activities, power generation, transportation and level of poverty are some of the anthropogenic causes of climate change in Sub-Saharan Africa.
Improvement of the welfare of the people through provision of social amenities and job creation, power generation through renewable energy,enlightening people about the danger of climate change and provision of alternatives sources of fuel to people at affordable price are some of the solutions to climate change threats in Sub-Saharan Africa.