Climate change adaptation by smallholder farmers in Southern Africa: a bibliometric analysis and systematic review

Climate change adaptation research is currently a policy priority. For smallholder farmers, it provides opportunities for resilience building. The research area is growing rapidly and calls to synthesize existing data have been made. Existing work forms a basic picture of the trends in the research area. However, it is limited in scope and methodological approaches used. This work synthesizes climate change adaptation research on smallholder farmers in Southern Africa. It gives an overview of past and current directions of climate change adaptation research using a combination of bibliometric analysis techniques and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Results show a steady growth in research, a disproportionate distribution of research and weak research collaboration among Southern African countries. Diverse methodologies are in use but a combination of approaches is rare. Co-occurrence of keywords show recognizable strides in research ranging from adaptation to mitigation linkages to the influence of climate change impacts on adaptation and livelihood outcomes. Strengthened research collaboration between countries in Southern Africa should be advocated for. This would help develop viable, appropriate and localized adaptation solutions. Equitable allocation of funding is pertinent to ensure uniform research activity and adaptation action across the region. A combination of research approaches is needed to push forward adaptation research on smallholder farmers in Southern Africa.


Introduction
Research on Climate Change Adaptation (CCA) is an important policy priority at the global, regional, national and individual levels.One of the main goals of the 27th Conference of Parties (COP 27) held in Egypt was to ensure an enhanced global agenda for adaptation action.For regions like Southern Africa, limited resources and low adaptive capacity (United Nations Framework Convention on Climate Change (UNFCCC) 2011) makes CCA research important.National governments of countries in Southern Africa are demonstrating the necessary political will by streamlining CCA in policy agendas to enhance adaptation action in vulnerable communities.For smallholder farmers, CCA provides opportunities of progress towards building resilience.
CCA research is also important for identifying scalable and transferable practices that assist communities to learn by doing, showcasing the strategies that are adopted and whether they are adequate and effective (Currie-Alder et al 2021).Research in the field informs governments to effectively develop localized interventions that help communities adapt accordingly.Findings from CCA research assist in identifying areas that are more in need of assistance (Karki et al 2022).This aids efficient resource allocation for climate 'hotspot' areas.
The importance of CCA research cannot be undermined, however, some gaps in existing CCA research have been identified.For example, Adamson et al (2018) observed that existing literature lacks a historical focus important in grounding adaptation strategies and fails to uncover path-dependence processes that ensure equitable adaptation.A divide exist between the past and present CCA research.Dorward et al (2020) observed complex and divergent views in studies comparing farmers' perceptions of climate changes and meteorological analysis based on historical climate assessments.This means that present-day farmers' perceptions of climate change should not inform adaptation in isolation but should be incorporated with past meteorological data.This calls for integration of disciplines and participatory research to advance CCA research.
An important gap which forms the basis of this review is the 'attribution gap' (Callaghan et al 2020) where adaptation-related research in developing countries is less compared to developed countries.This challenge is compounded by topic biases in adaptation related research where in the global south attention is mainly on disaster and development related topics while in the global north focus is on governance issues (Sietsma et al 2021).This illustrates that existing knowledge about CCA in Africa and in particular Southern Africa relies much on evidence from global studies that use data obtained elsewhere (Zhao et al 2021).This is problematic because issues pertinent at a global level may be inadequate to solve regional problems.
Despite the gaps and challenges in CCA research, notable advancements have been made in the field.CCA research has evolved from a purely scientific to a complex socio-political and economic phenomenon (Solomon 2007).The field has broken traditional boundaries (Deppisch and Hasibovic 2013) from using basic approaches to trans-disciplinary approaches (Mauser et al 2013, Serrao-Neumann et al 2015) that incorporate multiple aspects of adaptation experiences.The field has also evolved from only focusing on the problems in CCA to solution-oriented research (Adamson et al 2018).
The progress made in CCA research is vast in terms of breadth and scope.It is argued that CCA literature is in greater need of synthesis to track its development and see how far it has come and where it should be going.The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6) (IPCC 2022) recommended comprehensive reviews of scientific literature on adaptation to assess progress, enable better understanding, facilitate knowledge sharing and identify persistent gaps.
The work that has been done so far in synthesizing CCA research is appreciated, however some of these works are more focused on the biophysical aspects of climate change research and only include adaptation into the mix (Haunschild et al 2016, Callaghan et al 2020).Of major importance to this review, work focusing on adaptation is largely at a global scale (Sietsma et al 2021) with only a few focusing on the regional scale.This is problematic because a global analysis would not give a true empirical picture of reality for Southern Africa.Furthermore, there is little work that focuses on describing past and current trends in CCA research for smallholder farmers who rely heavily on land-based livelihoods vulnerable to climate change (Mutenje et al 2019).
In terms of scope and methodologies used in existing literature reviews on CCA research for smallholder farmers in Southern Africa, the use of a combination of bibliometric analysis and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) is scarce.Existing reviews use either bibliometric analysis alone or PRISMA only.Rarely are the methods combined.For example, Li et al (2022) used bibliometric analysis alone to track knowledge domains and emerging trends for Climate Smart Agriculture (CSA), and focus was at a global level.Among the few reviews that combine the two methods is a research conducted by Chumky et al (2022) who tracked the research landscape for disaster-induced migration, however, focus was neither on a specific group nor in Southern Africa.Smallholder farmers were just thrown into the mix.
This review aims to highlight the direction that CCA research on smallholder farmers in Southern Africa has taken so far, and provide an indication for future directions using bibliometric analysis and PRISMA methods.It is envisaged that findings will inform national governments to make adaptation a priority just like mitigation (Pielke et al 2007) in Southern Africa.The intention is to assess whether adaptation support is translating into actions and compare adaptation actions across Southern Africa.It is hoped that findings will enlighten policy makers on the status and shortcomings in adaptation action (Berrang-Ford et al 2011).

Method
Bibliometric analysis and PRISMA techniques were integrated to highlight CCA research on smallholder farmers in Southern Africa.The aim was to ensure a robust and comprehensive analysis of the research field.

Data extraction and search words
The main data source used for the review is the Clarivate Analytics Web of Science (WoS) Core Collection due to its phenomenal reputation in contemporary research (Li et al 2018).Clarivate Analytics WoS was used because it offers credible and rigorous evaluation processes which guarantees reliable results and is accepted as a comprehensive data source (Pranckutė 2021).A keyword search of related terms in CCA research was done in Clarivate Analytics WoS on the 26 August 2023.The term 'Climate change' was combined with search terms 'adaptation', 'adaptation measures', 'adaptation strategies', 'adaptive capacity', 'climate resilience', 'climate risk management', 'coping strategies', 'coping with climate change' for the initial search.A total of 289156 articles were retrieved.Since focus was on CCA research on smallholder farmers in Southern Africa, the results of the initial search were refined in two stages.First, a search within the results was conducted using search terms 'smallholder farmers' OR 'small-scale farmers'.This yielded 2198 articles.
The search results were filtered to capture research conducted in Southern Africa, the search was limited to research in South Africa, Zimbabwe, Malawi, Zambia, Botswana, Mozambique, Namibia, Lesotho, Swaziland and Angola as these countries cover the geographical region of Southern Africa.This yielded 431 articles which were exported as plain text format and used for the bibliometric analysis.Figure 1 is a flow diagram depicting the steps followed during data extraction for the bibliometric analysis.
Growth trend of CCA research on smallholder farmers in Southern Africa was tracked using, the Clarivate WoS analyze tool.It was established using the number of articles published per year.The distribution of CCA research on smallholder farmers in Southern Africa was established using the number of articles published for each of the countries.To track co-occurrence of keywords and co-operation in CCA research, the search result of 431 articles was exported as plain text into Visualisation of Similarities (VoS) Viewer software for analysis.A co-occurrence analysis of all keywords and co-authorship analysis between countries were conducted.For the co-occurrence of all keywords analysis, the minimum number of occurrences of a keyword was set on 5 as this facilitated better visualization and better emphasis of the more prominent keywords.Likewise, for the coauthorship analysis, the minimum number of documents per country was also set on 5 occurrences.
Results were presented using network visualizations.The network visualization for the co-occurrence of keywords analysis produces a set of clusters that group related keywords.Label and node sizes as well as link strength between nodes and labels on the network visualizations were used to interpret results.For cooccurrence analysis, the larger the label and node size, the higher the co-occurrence of a keyword.For coauthorship analysis, the higher the label and node size the higher dominance of co-operation with other countries.Table 1 summarizes the terms utilized by VoS Viewer in the bibliometric analysis conducted for the review.

Preferred reporting items for systematic reviews and meta-analyses
The review also sought to identify common research methods and establish key findings in CCA research for smallholder farmers in Southern Africa.To achieve these objectives the PRISMA guidelines (Moher et al 2009) were used.The 431 articles on CCA for smallholder farmers in Southern Africa identified from Clarivate WoS Core Collection and used for the bibliometric analysis were used as the starting point for the selection of relevant articles.Editorials, retracted material, conference proceedings and studies conducted outside Southern Africa were removed prior to the screening process.Therefore, 354 articles were eligible for the screening process.Title and abstract screening were conducted looking at whether the articles were within the context of the review.To gain comprehensive insights on the main thematic areas of smallholder farmers' CCA research and how it has evolved over time, highly cited articles (with at least 5 citations) were identified particularly for the review.Furthermore, the most current research articles, those published within the last five years (2019 to 2023) were chosen for full text analysis.Thus, only 87 articles were included for full text analysis with citations ranging from 5 to 132.The 87 articles were used to establish common methodological approaches and key findings on CCA research on smallholder farmers in Southern Africa. Figure 2 shows the stepwise procedure based on PRISMA guidelines.

Results and discussion
The results of the analysis are presented and discussed in this section.The section starts by presenting results from the bibliometric analysis and findings of the PRISMA method follows.

Development of CCA research on smallholder farmers in Southern Africa
Figure 3 shows the growth and development of CCA research on smallholder farmers in Southern Africa.The first article from the search results was published in 2001.The article utilized the participatory approach of Farmer Research Groups (FRGs) to establish the potential of incorporating pasture legumes for green manuring in maize production among small-scale farmers in Luapula Province, Zambia (Steinmaier 2001).The participatory nature of the approach used in the study promotes self-help among small-scale farmers which  Attribute of each link, expressed by a positive numerical value.In the case of co-authorship links, the higher the value, the higher the number of publications the two researchers have co-authored.

Network
Set of items connected by their links.

Cluster
Sets of items included in a map.One item can belong only to one cluster.

Weight attribute: Number of links
The number of links of an item with other items.Weight attribute: Total link strength The cumulative strength of the links of an item with other items.There is a noticeable increase in research from 2015 with the highest number of publications recorded in 2021.The increase from 2015 could be attributed to the establishment of the Sustainable Development Goals (SDGs) of the United Nations (UN).The SDGs agenda was set to establish improved and more sustainable future for all.Research efforts towards achieving this aim were accelerated.This could have correspondingly accelerated CCA research on smallholder farmers in Southern Africa.
The increase is in line with observations made by Callaghan et al (2020) who provided a topography of climate change research and observed that adaptation was one of the fast-growing topics and contained more citations in IPCC reports compared to other topics.Haunschild et al (2016) concurred and mentioned that CCA research is a topical issue in several major scientific fields including natural science, engineering, social and political sciences.Davidson (2016) provides evidence to this claim through a content analysis assessing the contribution of social sciences to CCA research.The main observation was that research attention on CCA research in agriculture is increasing substantially, with a rise in the proportion of studies focusing on developing countries and an overall growth in contribution of social science.

Distribution of CCA research on smallholder farmers in Southern Africa
Figure 4 shows the distribution of CCA research in Southern Africa.A huge gap is observed in terms of research conducted between South Africa and other Southern African countries, with absolutely no publications on WoS in Angola and Eswatini during the period under analysis.South Africa dominates the research field as shown by the dark blue colour, followed by Zimbabwe.
Results tally with previous analyses that reveal spatial differences in CCA research across the world.For example, Overland et al (2021), Sietsma et al (2021), Vincent and Cundill (2021) observed a larger empirical research focus on adaptation options for South Africa than any other country in the Southern African region.This may be explained by the funding pattern with South Africa having received most adaptation funding compared to other Southern African countries Hendrix (2017), Overland et al (2021).Hendrix (2017) links this inequality to 'the streetlight effect' which is described as researcher bias towards certain countries while overlooking other countries are equally in need of research attention.This explains why the distribution of CCA research is skewed towards South Africa.The challenge influence research activity including participation, implementation and communication.

Co-operation in CCA research on smallholder farmers in Southern Africa
Figure 5 shows a co-authorship network of countries publishing CCA research on smallholder farmers in Southern Africa.In general, the network shows a weak collaboration among countries in Southern Africa as they are mostly found in different clusters.The red cluster only has one Southern African country, while the yellow and blue have only 2 countries and the green cluster has none.There is however, a notable collaboration between South Africa and Zimbabwe as indicated by the thickness of the link between the two countries.The strong collaboration between South Africa and Zimbabwe can be attributed to the large number of trained scientists who have migrated to South African institutions of higher learning due to the economic meltdown who are establishing collaborations with colleagues back home.The strong collaboration could also be due to the fact that the two countries share borders and share a number of trans-boundary projects directed towards research activities between the two countries.

Co-occurrence of keywords in CCA research on smallholder farmers in Southern Africa
The analysis of the co-occurrence of keywords showed that out of 766 keywords in CCA research on smallholder farmers in Southern Africa, only 61 met the threshold.The top ten most occurring keywords are shown in Table 2 with total link strength ranging from 121 to 357.
The analysis of the co-occurrences of keywords in CCA research for smallholder farmers yielded five different clusters.The clusters were interpreted using keywords with largest nodes and labels since size represents higher occurrence of keywords in published articles.Figure 6 shows the resulting clusters.

Cluster 1 (Red): Adaptation and mitigation linkages
The red cluster grouped 16 keywords whose thematic focus is adaptation and mitigation linkages.Keywords 'Climate Smart Agriculture, Conservation Agriculture (CA), mitigation are found in this cluster.The cluster reflects the importance of integrating adaptation and mitigation in smallholder farming.Nonetheless, Harvey et al (2014) noted that the two processes are often pursued as separate activities and are rarely linked which reduces effectiveness in achieving wider conservation goals.Results of this review reflect this observation with only 14% of the articles included in the analysis exploring adaptation and mitigation linkages for smallholder farmers in Southern Africa.
Among the few studies, agro-forestry is recognized as a potential measure that can assist farmers in climate adaptation and mitigation (Coulibaly et al 2017).CSA also has both adaptation and mitigation benefits.Nyagumbo et al (2022) evaluated the merits of climate-smart technologies in Malawi and observed that CA, maize-pigeon pea intercropping and a local organic and inorganic soil amendment known as Mbeya fertilizations had higher potential for carbon sequestration, increased productivity, improved gross margins and enabled farmers to be more resilient and adapt better thereby improving food security and livelihoods.Madembo et al (2020) observed that maize-jack bean, maize-cowpea and maize-pigeon pea + cowpea intercrops resulted in more stable and less variable yields for smallholder farmers in Zimbabwe and would help reduce climate related risks.However, Madembo et al (2020) cautioned against planting these legumes in between or in the same rows with maize as this may create competition.Instead, the use of double row strips was recommended.
Adaptation and mitigation are two of the three pillars of CSA with food security being the third pillar (van Wijk et al 2020).In the context of CSA, adaptation is intended to enhance resilience while mitigation aims to reduce agriculture's contribution to climate change.Conservation Agriculture is an important example of CSA because it delivers all three aspects: adaptation, mitigation and food security also referred to as the 'triple-win effects' (Abegunde et al 2019a).
Despite the role of CSA in meeting the objectives of adaptation and mitigation linkages in the quest for protecting and transforming the agricultural sector (Okolie et al 2023), Thierfelder et al (2017) found out that  information on mitigation potential of CA, as a CSA approach, among smallholder farmers in Southern Africa is lagging due to insufficient data that is often contradictory and misleading.For example, Abegunde and Obi (2022) analyzed the state of CSA in Africa including some countries in Southern Africa and showed that poor availability of data hindered its uptake among smallholder farmers.Poor access to resources, widespread poverty, dilapidated infrastructure and lack of advisory services also limit adoption of CSA (Mutengwa et al 2023).The use of indigenous practices also demonstrates the importance of adaptation and mitigation linkages.Rankoana (2022) notes that small-scale farmers in Limpopo Province South Africa adopted the growing of indigenous crops like millet, sorghum, melons and nuts that assist in both adaptation and mitigation objectives stipulated in the South African National Climate Change Strategy.Such crops improve food production while minimising the risks of climate change.This shows that progress has been made towards establishing and meeting adaptation and mitigation linkages among smallholder farmers in Southern Africa.Although indigenous and traditional knowledge systems are a major resource for adaptation and mitigation, they are not sufficiently acknowledged and integrated as demonstrated in Chirumanzu District of Zimbabwe (Grey and Manyani 2020).

Cluster 2 (Green): Farmers' perceptions of climate change and adaptive behaviour
The green cluster grouped 14 keywords used in CCA research on smallholder farmers in Southern Africa.Keywords 'perceptions, adaptation strategies' management and information are found in this cluster.The cluster reflects the importance of farmers' perceptions in influencing adaptive behaviour.The process of individual adaptation to climate change among smallholder farmers is strongly influenced by perceptions.Perceptions of climate change come in three dimensions (Grothmann and Patt 2005).First, it is the ability to observe and be aware of climate change (Hyland et al 2016).Studies included in the analysis shows that smallholder farmers in Southern Africa have made progress in this aspect.For example, early research work by Mubaya et al (2012) smallholder farmers in Zambia and Zimbabwe were able to perceive and explain diminishing agricultural production in terms of climate variability.
Second, perceptions of climate change can be the ability to identify the impacts of climate change stressors on farming (Talanow et al 2021).Smallholder farmers in Southern Africa have also made progress in this aspect as shown by studies included in the analysis.
uMhlanga-Ndlovu and Nhamo (2016) showed that smallholder farmers in Swaziland were able to link climate extremes such as drought and flood incidences, temperature fluctuations, decreased water availability, and increased pests and diseases, to reduced production in sugarcane farming.
Third, perceptions of climate change can be the ability to perform appraisals of the probability of exposure to climate related risks (Grothmann and Patt 2005).This has a bearing on the level of preparedness for climate change events.Research shows that although smallholder farmers in Southern Africa may be able to perform individual appraisals, their perceptions are marred by several biases.Waldman et al (2019) found evidence of cognitive bias among smallholder farmers in Zambia where they perceived late onset of rains.Mubaya et al (2012) made an important observation that smallholder farmers in Zimbabwe and Zambia were not able to distinguish the contribution of social, economic and political factors from the effect of climate variability on agricultural production.
Despite the importance of perceptions in adaptation, the relationship between perceptions and adaptation to climate change is not always linear (Wiid and Ziervogel 2012).This is because they are multiple factors such as non-cognitive factors that come into play and can influence adaptive behaviour.Chipfupa et al (2021) illustrated that self-confidence, optimism and hope can also influence adaptation behaviour among smallholder farmers in Jozini, KwaZulu Natal, South Africa.Contrastingly, Phiri et al 2019 observed that despite expert advice on the benefits of adopting small grains such as sorghum and millet, smallholder farmers in Zimbabwe are resisting.The perceptions and attitudes of smallholder farmers towards small grains influenced by cultural beliefs and consumer preferences discredit its adoption as a climate resilient crop.

Cluster 3 (Blue): Food security-sustainability-resilience nexus
The blue cluster grouped 13 keywords.Keywords food security, resilience sustainability and livelihoods fall in this cluster.The articles that mentioned these keywords depict the theme 'food security, sustainability and resilience nexus'.The cluster reflects the complex relationship between and among food security, sustainability and resilience.Food security is a concept that has evolved over the years.Several definitions have been developed; however, they all converge on the same idea.The Food and Agricultural Organization (FAO) and the Committee on World Food Security (CFS) defined 'food security as a situation when all people have physical, social and economic access to sufficient, safe and nutritious food that meet their dietary needs and food preferences for an active and healthy life at all times' (FAO 2003: chapter 2; CFS 2012: 6-7).This definition provides four important dimensions of food security, these are availability, accessibility, utilization, and stability (Peng and Berry 2019).
Southern Africa lacks the potential to meet the required amounts of food for its increasing population, compromising regional food security targets.This is because Southern Africa is a climate change hotspot, has low adaptive capacity, is underdeveloped and marginalized (Nhamo et al 2019).South Africa is known to be food secure at the national level but food insecure at the household level particularly in remote villages.According to Statistics South Africa (2022), more than 23% of South Africans were affected by moderate to severe food insecurity in 2020, while nearly 15% experienced severe food insecurity.Zimbabwe's food security status remains fragile due to the recurring droughts and floods, erratic rainfall, and long dry spells.In 2019, the Zimbabwe Vulnerability Assessment Committee estimated that 5.5 million rural Zimbabweans were food insecure.In Mozambique, an adequate diet is not affordable for 80% of the population who cannot afford it (World Food Programme 2022).To achieve food security in Southern Africa, there is need to ensure sustainability in the food systems.
The notion of 'sustainable diets' (Gussow and Clancy 1986) links food security to sustainability.'Sustainable diets are diets with low environmental impacts, contribute to food and nutrition security and healthy life for present and future generations' (FAO 2010: 7).Meybeck and Gitz (2017) postulated that sustainable food systems enhance the adoption of sustainable diets.This could be why sustainable agriculture is a priority in the SDGs agenda of 2015 with Goal-2 aiming to end hunger, achieve food security and improve nutrition and promote sustainable agriculture by 2030.Nevertheless, Southern African countries continue to battle with low agricultural production linked to unsustainable agricultural practices that are in continual use among smallholder farmers.Siulemba and Moodley (2014) noted that low productivity in Zambia was mainly due to the long-term use of unsustainable agricultural practices.It was also established that lack of knowledge of sustainable agricultural practices was the major constraint for females in Chankumba agricultural community, Zambia.
Closely related to both food security and sustainability is the concept of resilience (Keskinen et al 2019).Sustainable food systems and diets can only be a reality if agricultural systems are resilient.Agricultural systems need to be resilient to climate change to build sustainable food systems and diets.Resilience is a measure of the ability of an agricultural system to survive and persist within a variable environment that sees different kinds of changes over time (Meadows 2008).In Southern Africa, resilience among smallholder farmers is generally low (Field et al 2012).Maltou and Bahta (2019) established that only 9% of smallholder livestock farmers in the Northern Cape, South Africa were resilient to drought.However, efforts are being made to improve smallholder farmers' resilience.Jiri et al (2017) posited that understanding adaptation is important in developing and implementing effective measures that can lead to improved resilience among smallholder farmers in semi-arid areas of Zimbabwe.Government assistance (Maltou and Bahta 2019) and women empowerment (Maltitz and Bahta 2021) could help build smallholder livestock farmers' resilience in South Africa and is recommended as a way of improving resilience among female livestock farmers.Mugari et al (2020) reckons that knowledge of the factors which affect decisions concerning adaptation is critical towards developing resilience in semi-arid rural areas of Botswana.

Cluster 4 (Yellow): risk and vulnerability
The yellow cluster grouped 11 keywords focusing on the theme, risk and vulnerability.The cluster shows the importance of risk and vulnerability assessments for smallholder farmers.It is generally accepted that assessing vulnerability of smallholder farmers enables clearer and more effective adaptation responses directly targeted towards them (Barsley et al 2013).Smallholder farmers in Southern Africa are highly dependent on rain-fed agriculture.This increases their exposure and sensitivity to climate change which are both components of vulnerability.Effects of a changing climate in north-central Namibia has resulted in unpredictable and variable rainfall for the past 30 to 40 years characterized by a variable pattern and shorter rain seasons making subsistence and small-scale farmers vulnerable (Angula and Kaundjua 2016) as their farming activities are highly dependent on rainfall.
Vulnerability varies from one farmer to the next because of social, cultural and geographical differentiation (Birkmann et al 2021).Spear and Chappel (2018) showed that social dependence contributes significantly to social vulnerability among smallholder farmers in Namibia.The same study illustrated that Namibian smallholder farmers' mindsets shaped by traditional customs, religious opinions and dependence on government worsens their vulnerability.Geographically, Hosu et al (2016) showed that current and future vulnerability of smallholder farmers is characterised by different agro-ecological zones in the Eastern Cape, South Africa and rain-fed agricultural activities in the Savannah were the most vulnerable while least vulnerability was observed in the Karoo.
Southern African countries have made progress in carrying out vulnerability assessments.There is an increase in vulnerability assessments for smallholder farmers across sub-Saharan Africa including countries in Southern Africa like Mozambique, Swaziland, Botswana and Zimbabwe (Williams et al 2018).However, some key gaps exist which include non-inclusion of local views, lack of clarity on the concept of vulnerability, generalizations in criteria used in measuring vulnerability and limited relevance of assessments in offering decision support to smallholder farmers (Williams et al 2018).
Mavhura (2019) proposed five important policy recommendations.Although the recommendations were specifically for smallholder farmers vulnerable to hydro meteorological threats in Northern Zimbabwe, they may be applicable elsewhere in Southern Africa.The recommendations include land-use use zoning into safe and unsafe areas, resettlement from unsafe floodplains, promoting a shift from rain-fed to irrigation cropping systems, enhancing adoption of drought tolerant and short-season varieties as well as promoting livelihood diversification.It is envisaged that this will reduce vulnerability by reducing exposure and sensitivity while improving adaptive capacity of smallholder farmers.
3.4.5.Cluster 5 (Purple): Impacts, adaptation and livelihood outcomes The purple cluster grouped 7 keywords showing the influence of climate change impacts and adaptation on livelihoods.Climate change impacts, adaptation and sustainable livelihoods scholarship are well interconnected however, Connolly-Boutin and Smit (2016) observed that they have evolved separately.This has led to a disconnect in the development of effective policies and programs that strengthens resilience among smallholder farmers.Appreciation and recognition of the interconnectedness would be the first step towards achieving positive livelihood outcomes for smallholder farmers in Southern Africa.
Climate change is a huge challenge with negative impacts on livelihoods especially for smallholder farmers (Cohn et al 2017) in Southern Africa.Impacts of increased temperatures, unpredictable rainfall and extreme weather events, increased incidence of pests and diseases on crop yields and livestock production threaten smallholder farmers' livelihoods (Harvey et al 2018).Smallholder farmers adopt a myriad of strategies to curb the negative impacts.Some of the strategies include the use of common natural resource pools such as wetlands and woodlands in Hwedza District, Zimbabwe (Chagumaira et al 2016) There are many advantages associated with adaptation among smallholder farmers.Smallholder farmers in Limpopo and Free State Provinces of South Africa adapted through growing maize substitutes like sunflower, sorghum and groundnuts improved economic and financial gain than when they used to grow maize (Kephe et al 2022).Khoza et al (2019) realised the social benefits of an innovative blend of both contemporary and classic gender mainstreaming approaches in CSA research, practice and technology development in Malawi and Zambia.The analysis shows that an understanding climate change impacts and adaptation outcomes on smallholder farmers' livelihoods is important.Effective adaptation is required to accomplish maximum benefits on different components of livelihoods (Moser and Ekstrom 2010).This brings desirable livelihood outcomes.Table 3 describes the resultant clusters and emerging themes.It also shows a selected set of research articles depicting each theme, location of the research and the authors.

Methodological approaches in CCA research on smallholder farmers in Southern Arica
The methodological approaches used in CCA research on smallholder farmers in Southern Africa are diverse.Data collection is mainly conducted through large scale surveys based on interviews (e.g.Popoola et al 2018, Bahta 2020).In some instances, small-scale case studies based on key-informant interviews were conducted (e.g.Khoza et al 2019).Face to face interviews were most common while key informant interviews were less used.Researchers relied more on interviews possibly because of the nature of the research field which is inclined to social sciences than natural sciences.The approach helps to understand CCA from the actual subjects with firsthand information and experience.
Questionnaires were the most used data collection tool.Both structured and unstructured questionnaires were used (e.g.Abegunde et al 2019a, Myeni et al 2021).CCA research that used structured questionnaires made use of closed-ended questions so that participants could remain focussed.Research that made use of unstructured questionnaires made use of open-ended questions and allowed the researcher to explore more about the research theme.On-farm and on-site experiments were also used (e.g.Madembo et al 2020).These were mainly used to establish and illustrate the effects of different types of climate adaptation strategies on production.Data were also collected using transect walks (e.g.Mavhura 2019) and observations (e.g.Manyati and Mutsau 2019).These were useful in explaining and illuminating the cause-effect relationships in less predetermined circumstances.
Analytical methods used in CCA constituted both quantitative and qualitative tools.Quantitative data was analysed using several complex statistical tools such as Binary Logit Model (e.g.Kgosikoma et al 2018), Heckman Probit Model (e.g.Mutandwa et al 2019) and Ward Linkage Cluster Analysis (e.g.Popoola et al 2018) while qualitative data were analysed through thematic content analyses (e.g.Mogomotsi et al 2020).Statistical tools and techniques dominated compared to qualitative tools possibly because of researchers' preference of quantitative over qualitative analyses.
It could also be because quantitative analyses produce results that are considered more scientific, objective and focussed than qualitative analyses.A combination of the quantitative and qualitative methods is rare.Combining the two, (e.g.Mogomotsi et al 2020) could enhance rigour and improve research findings in the field.
GIS and remote sensing were applied in mapping areas vulnerable to drought in Southern Africa (e.g.Shikwambana et al 2021).This assist policy makers in developing appropriate adaptation strategies (Lottering et al 2021).The use of transdisciplinary studies is slowly gaining momentum in CCA studies in Southern Africa.For example, Chagumaira et al (2016) used remote sensing, GIS and participatory approaches to demonstrate the importance of Common Natural Resource Pools (CNRPs) for CCA in Zimbabwe.

Key findings on CCA research on smallholder farmers in Southern Africa
Full text reading provided important insights that were grouped into five themes as explained in the following section.

Determinants of adoption
There are drivers that influence the way smallholder farmers respond to climate change.Abegunde et al (2019a), Kom et al (2020) established that farmer attributes and farm characteristics affect the type and choice of adaptation measures by different farmers in KwaZulu Natal and Limpopo Provinces, South Africa, respectively.Therefore, smallholder farmers adopt a variety of measures to reduce climate change effects.This illustrates farmer heterogeneity reflecting different adaptation reaction paths in response to climate change.
Abegunde et al (2019b), Khoza et al (2019), Kom et al (2020) raised an important dimension of gender as one of the determinants of adoption.Climate change affects men and women differently because gender influences power, responsibility and roles in households and communities and most women are trapped in cultural and traditional gender norms (Maltitz and Bahta 2021).This leads to an imbalance in economic opportunities and limited access to resources such as financial capital to invest in adaptation making their position weak in adaptation decision-making.
Although smallholder farming is dominated by females in Southern Africa, the analysis of the effect of gender showed conflicting results in South Africa.Abegunde et al (2019b) established that although gender may be significant, it negatively affected the adoption of CSA in KwaZulu Natal, South Africa.On the other hand, Kom et al (2020) found gender to be one of the significant drivers of adoption in Vhembe District, Limpopo.The conflicting results could be a result of the different circumstances of women who participated.Their study shows that Western gender approaches are not applicable to the realities of smallholder farmers in Southern Africa.The authors argue that Western gender approaches for CSA in Malawi and Zambia are aimed at fulfilling donor interests, disregarding the underlying socio-cultural issues shaping gender in both countries.Western gender approaches such as the Western-hegemonic feminism, centre on inclusion of all women under a shared and imposed identity disregarding other identities outside the model.
Other Western gender approaches include the Women in Development (WID) and Gender and Development (GAD).These approaches are anchored by the traditional feminist theories and inform gender mainstreaming for CSA adoption (Collins 2017).However, it has been noted that they fail to address gender issues including women's disempowerment and marginalisation in developing countries.Thus, it is recommended that African and Western gender approaches should be integrated to pave way for inclusivity of the realities of women smallholder farmers in Southern Africa.

Institutional support
The theme, institutional support emphasizes the important role played by institutions in enhancing adaptive capacity of smallholder farmers under a changing climate.Mogomotsi et al (2020) identified three types of institutions that play different roles in enhancing adaptive capacity of smallholder farmers in Botswana.These are local public, informal and national public institutions.The local public institutions are extension services who oversee farming activities in local communities.The review established that smallholder farmers in Botswana do not see much value of the local public institutions as they considered them biased towards more resourced farmers and less responsive to the needs of other smallholder farmers.As such, they rely more on the informal institutions such as farmer-to-farmer extension for information, knowledge and resources.
Other support institutions that smallholder farmers rely on include agro-finance institutions, banks and Non-Governmental Organizations (NGOs).They offer support such as capital, machinery, inputs such as seed, fertilizer and chemicals as well as educational support.To enhance the role of institutions, it is important to note that support needs of smallholder farmers vary.Kephe et al (2020) observed that support needs of smallholder farmers in Limpopo, South Africa varied across agro-ecological zones.The recommendation was that support should be location-specific to enhance adaptive capacity of smallholder farmers.

Livestock-based adaptation strategies
The theme livestock-based adaptation strategies emerged from studies including Bahta (2020) who investigated livestock smallholder farmers' coping strategies under drought conditions in Frances Baard District, Northern Cape, South Africa.Generally, focus on livestock-based adaptation strategies is limited compared to crop-based adaptation strategies in literature.This is a challenge for smallholder livestock farmers because they are tempted to make use of crop-related information on climate change for livestock (Ntombela 2017).Bahta (2020) found that the major coping strategy adopted by livestock smallholder farmers in Frances Baard District, Northern Cape Province, South Africa was selling-off livestock.Results depict narratives in existing literature on reliance on unsustainable means of survival among smallholder farmers when confronted with difficult situations (Harvey et al 2014) like climate change.To cushion the effects of the drought, smallholder farmers resort to unsustainable means of survival (Torres-Vitolas et al 2019).However, this makes smallholder farmers worse-off.
Other strategies reported were reducing production through culling, selling off assets and completely stopping livestock farming.These measures are in line with the phenomenon of deagrarianization in South Africa where deanimalization (Musial and Musial 2019) has become a common feature.Zantsi and Bester (2019) provided evidence of deanimalization in Amathole District, Eastern Cape where it was shown that the average herd composition of the households who participated in the study was very low.

Adaptation constraints
The theme adaptation constraints emerged from studies including Popoola et al (2020).The theme illustrates the barriers to adaptation (Biesbroek et al 2013) facing smallholder farmers.Adaptation constraints were equated to barriers of adaptation in this review.These are conditions that hamper the ability to adapt proactively.Although smallholder farmers face several constraints in adapting to climate change, Popoola et al (2020) ranked lack of access to agricultural extension services as the most critical constraint for farmers in Amathole District Eastern Cape.Extension services are important in building adaptive capacity of smallholder farmers.Southern Africa's extension services face many challenges.For example, in Zimbabwe high extension officer to farmer ratio, lack of transport to reach targeted communities are some of the issues that hamper access.Extension service delivery should be made a critical policy priority to enhance smooth flow of information to smallholder farmers.

Resilience building
Building the resilience of smallholder farmers is crucial in Southern Africa where climate changes are common and adaptive capacity is low.Some studies included in the review illustrated ways in which resilience among smallholder farmers can be strengthened.Access to credit facilities, training, provision of inputs and involvement in cooperatives and social networks are important in enhancing resilience to drought in South Africa (Maltou and Bahta 2019).CNRPs such as wetlands and woodlands were important in enhancing resilience of smallholder farmers' communities in Zimbabwe through providing food and generating income (Chagumaira et al 2016).However, farmers were cautioned against over-reliance on these CNRPs as it causes tremendous decline.Use of other farm management options that increase crop and livestock production should be designed to reduce pressure on CNRPs.Table 4 provides a summary of the methodological approaches used in CCA research for smallholder farmers in Southern Africa and the key findings.Research has shown that adoption is constrained by a number of factors including financial resource constraints, lack of expertise, limited access to agricultural inputs ecological settings, labour bottlenecks (Abegunde and Obi 2022, Ariom et al 2022), Several recommendations aimed at improving adoption of CSA practices have been suggested to enhance CSA adoption among smallholder farmers in Southern Africa.Abegunde et al (2019a) posits that farmer associations and groups and improving contact between farmers and extension officers could facilitate adoption of CSA.van Wijk et al (2020) advocates for a combination of the empirical and theoretical approaches in CCA research to ensure that all the three pillars of CSA, food security, mitigation and adaptation are achieved.

Past and current issues in CCA research on smallholder farmers in Southern Africa
Current research on CCA on smallholder farmers also points to sustainability constraints of some adaptation measures.Farmers practicing irrigation in perennial dry areas are confronted with sustainability constraints that limit them from realising the full potential of adaptation.Muhoyi and Mbonigaba 2021 observed that variation in water distribution, water pricing, the absence of regular and efficient maintenance of the pumps, poor state of irrigation infrastructure, poor agronomic practices, lack of markets soil erosion and siltation issues could threaten the sustainability of the Mutema, Tawona, Bwerudza and Charuma irrigation schemes in Chipinge District, Manicaland Province, Zimbabwe.
An important finding on CCA research on is that there is low awareness of CCA policies, sensitization campaigns are limited and capacity building training are lacking among smallholder farmers in Southern Africa.Popoola et al (2020a) found that 89% of the farmers who participated in the study did not know about the South African National Climate Change Response Policy while 90% claimed nothing has been done for public sensitization of the policy.This portrays a gloomy picture when considering the increasing climate change impacts and the high vulnerability status of smallholder farmers in the region.Immediate government intervention is required to ensure that appropriate adaptation education and support is rendered to smallholder farmers.

Conclusions
The synthesis of CCA literature on smallholder farmers in Southern Africa is pertinent to track its development, identify gaps and strategize on ways to enhance effective adaptation.Although, several works have been done, a number of gaps exist.In terms of scope, there is less focus of synthesized literature on a regional scale while focus on smallholder farmers is also limited.In terms of methods used for synthesizing the literature, a combination of the bibliometric analysis and PRISMA techniques is rare.Hence, this review paper aimed to synthesize CCA research on smallholder farmers in Southern Africa using a combination of bibliometric analysis and PRISMA techniques.Focus was on the development trend, common keywords, methodological approaches, key findings, distribution and co-operation between institutions.
Results show that CCA research on smallholder farmers in Southern Africa is developing at a steady rate.CCA research on smallholder farmers in Southern Africa is mainly concentrated in South Africa followed by Zimbabwe.Results show weak research collaboration among countries in Southern Africa.It is recommended that research collaboration should be strengthened to develop locally-based adaptation solutions for smallholder farmers in the region.The co-occurrence of keywords shows that CCA research on smallholder farmers in Southern Africa has made recognizable strides reflecting important adaptation and mitigation linkages, the role of farmers' perceptions in adaptation, the nexus between food security, sustainability and resilience, the significance of risk and vulnerability assessments and the influence of climate change impacts on adaptation and livelihood outcomes.Methodological approaches used in CCA research on smallholder farmers, although diverse, used either qualitative or quantitative methods with a combination of the two in one study being rare.
CCA research on smallholder farmers in Southern Africa illustrates a number of important aspects that are often overlooked/ masked in research conducted at a global level.These aspects are specific to the Southern African region and should be prioritized to ensure effective adaptation among smallholder farmers in the region.Gender emerged as one of the most important determinant of adoption of adaptation measures.Hence, national governments in the region should mainstream gender in CCA policies.Institutional support has been shown to enhance adaptive capacity of smallholder farmers in the region and should be provided according to the needs of different farmers.Research on livestock-based adaptation strategies on smallholder farmers in Southern Africa is less prioritized yet it deserves equal research priority so that livestock farmers do not depend on crop related information to adapt effectively.Lack of agricultural extension services is deemed one of the most critical constraint in the region hence it should be made a policy priority to enhance smooth flow of CCA information to smallholder farmers.Relying on research conducted at a global level would not suffice as it focuses less on regional priorities.Equitable allocation of funding for CCA research in Africa is paramount to ensure uniform distribution of CCA research as research led by external researchers may overlook local priorities.Researchers

Figure 1 .
Figure 1.Flow diagram of the steps followed for the bibliometric analysis.Source: Authors' conceptualization.

Figure 2 .
Figure 2. Flow diagram of the selection process based on PRISMA.Source: Authors' conceptualization.

Source:
Pauna et al 2019.enhances development through farmer emancipation and involvement in decision making of matters that concern them.Results show that in early years (2001 to 2015), research on CCA among smallholder farmers was limited.This may be attributed to a general lack of CCA research in highly vulnerable countries including Southern Africa as observed by Overland et al (2021), Sietsma et al (2021).Results provide evidence to claims made by Blicharska et al (2017) who noted a North-South divide in research relevant to climate change policy and practice.Despite contributing very little to climate change, Southern Africa is highly vulnerable, yet adaptation research is isolated (IPCC 2022).This may be because countries in Southern Africa are low to middle income countries.Possibly, during these early years their governments lacked funds to channel towards CCA research hence it was lagging.

Figure 3 .
Figure 3. Development of CCA research on smallholder farmers in Southern Africa.

Figure 4 .
Figure 4. Spatial coverage of CCA research on smallholder farmers in Southern Africa.

Figure 5 .
Figure 5. Co-authorship network of countries publishing CCA research on smallholder farmers in Southern Africa.

Figure 6 .
Figure 6.Network visualization of the co-occurrence of keywords on CCA research on smallholder farmers in Southern Africa.
, the use of climate information in livelihood decision-making in semi-arid lands of central Namibia (Gitonga et al 2020), staggering planting dates in Chimanimani District, Zimbabwe (Mutandwa et al 2019), crop diversification in OR Tambo District Eastern Cape, South Africa (Muroyiwa et al 2022), irrigation in the Midlands Province, Zimbabwe (Mwadzingeni et al 2021).
Figure 7 shows an overlay visualisation of the past and current issues in CCA research for smallholder farmers in Southern Africa.Previous research prior to and during 2018 and 2019 focused on climate change impacts, risk and vulnerability, adaptation and resilience.This is shown by the keywords grouped in the blue and turquoise clusters illustrating the first steps in CCA research for smallholder farmers in Southern Africa.Researchers attempted to understand the implications of climate change impacts and smallholder farmers' exposure especially on food security and livelihoods (Mavhura 2019).Researchers also sought to understand how smallholder farmers adapted to the climate changes.Studies on adaptation strategies adopted by smallholder farmers were closely aligned to building adaptive capacity and resilience (Mashizha 2019, Maltou and Bahta 2019).Enhancing adaptive capacity and building resilience is crucial for smallholder farmers because the livelihoods are derived from agriculture which is susceptible to climate extremes.Current research topics on CCA among smallholder farmers in Southern Africa shown by the keywords grouped in the green and yellow clusters.The studies are from 2020 onward and topics focused on CSA (Abegunde et al 2019a), mitigation (Chitakira and Ngcobo 2021), perceptions on CCA (Zinyemba et al 2020), sustainability constraints (Muhoyi and Mbonigaba 2021) and CCA policy formulation interventions and implications among smallholder farmers in Southern Africa (Popoola et al 2020a).CCA research on smallholder farmers illustrates low rates of adoption of CSA (e,g.Abegunde et al 2019a) despite the many benefits associated with the practices and this is an major concern.

Figure 7 .
Figure 7. Overlay visualisation of past and current trends in CCA research on smallholder farmers in Southern Africa.

Table 1 .
Terms utilized in VoS viewer for bibliometric analysis.
Term DefinitionItems Objects of interest (e.g., publications, researchers, keywords, authors).Link Connection or a relation between two items (e.g., co-occurrence of keywords) Link strength

Table 2 .
Ten most occurring keywords in CCA research on smallholder farmers in Southern Africa.

Table 3 .
Summary and interpretation of clusters.Khoza et al (2019) provides a different lens on gender based on CSA adoption among smallholder farming communities in Malawi and Zambia.

Table 4 .
Methodological approaches and key findings on CCA research on smallholder farmers in Southern Africa.