Building adaptive capacity of smallholder agriculture to climate change: evidence synthesis on learning outcomes

In addition to synthesising the scientific findings from the literature it is also important to consider how and where that evidence has developed over time. During the review process, key information was extracted to facilitate the production of summary statistics. SI figure 1 shows the temporal trend in relevant publications, and the rising and recent interest in the topic. As expected, most evidence (73%) was obtained from the peer reviewed literature, followed by technical project reports (18%) and book chapters (7%). There was also a noticeable rapid increase in the number of peer reviewed papers from 2016. SI table 4 shows there was a good balance between quantitative and qualitative based studies across all publication types. Regarding the quality assessment of the literature, in other disciplines, a 'hierarchy of research methodologies' is often used to score data in terms of its scientific rigour. However, this approach would not work in this study because the environmental context of each study provided too much 'internal' variability.

Regarding specific research topics, most of the evidence dealing with smallholder adaptation had a focus on farm management (29), followed by those on knowledge management (22) and governance and institutions (11). Only seven studies investigated specific issues linked to natural resources management, although some of the resources with a broader or multifaceted research scope classified 'other' (22) also dealt with environmental and natural resources issues (SI table 5). In terms of geographical focus, the literature included evidence from many different countries; however, sub-Saharan Africa was the most represented region (notably southern and East Africa), accounting for over half (53%) of all papers, followed by Asia and the Pacific (23%) and Latin America and the Caribbean (9%). A small proportion (15%) had a global or multi-country scope, but always with a focus on the Global South (figure 2). A fundamental question for the review was to assess the extent to which the available evidence would contribute to our understanding of the three learning outcomes. Most of the sources provided insights for 'scaling up', either directly (28%) or indirectly by addressing the determinants and barriers to the adoption of adaptive practices and behaviours by smallholders (24%). About a third (35%) provided insights in relation to knowledge management, whereas only 14% were relevant to human and ecosystem interactions.

Zoom In Zoom Out Reset image size

There is extensive empirical literature investigating the underlying conditions and enabling factors that determine the uptake of autonomous adaptation measures. These determinants were evaluated alongside the conditions and features of 'transformational' or more persistent adaptation pathways, usually framed in broader planned adaptation policies or interventions. Equity and inclusion considerations are also important determinants in the social and economic sustainability of smallholder adaptation. Access to knowledge is one of the most important determinants of smallholders' decisions to adopt climate change responses. It is also a critical element in building adaptive capacity. The way knowledge about the impacts of climate change and its variability—and of potential responses—is produced, transferred and exchanged is thus extremely relevant to securing scaling-up pathways.

Scaling up a process or initiative does not only imply bringing it to scale (to more people, and/or across a larger area) or adapting it to similar conditions in different locations (horizontal scaling up). It can also mean moving a project forward into a more developed, complex phase, possibly involving new components, configurations and stakeholders (diagonal scaling up). There can also be vertical scaling up which consists of mainstreaming a certain approach into policy, thus leveraging and catalysing policy and institutional change (Neufeldt et al 2015). This review thus explicitly considered the recurrent determinants including pre-conditions, capacities, drivers and triggers needed to secure effective scaling-up pathways. Two types of publication were relevant, namely (i) articles in the academic literature which explored the determinants and barriers to the adoption of practices and behaviours, and (ii) fewer articles and research papers which offered more articulated discussions on the long-term or transformational achievements of adaptation strategies. The former were quantitative analyses that considered a given population at one point in time to investigate possible correlations independent variables (gender, age, assets, social relations) and one or more dependent variables linked to the adoption of one or more changes in practice and/or behaviour. These studies were useful in tracing the underlying conditions and enabling factors that support farmers' decisions to respond to a particular risk—a critical step in planning adaptation. However, they often didn't provide deeper insights or understanding of what characterises sustainable and inclusive adaptation patterns over the longer-term.

Scaling up may also refer to 'social' scaling up (increasing social inclusiveness) and conceptual scaling up in terms of moving beyond participation to embedding empowerment in the entire development process (Binswanger-Mkhize et al 2009). A few studies addressed this broader definition by adopting a more dynamic, longer-term, and broader perspective in describing adaptation patterns. Some were case studies that investigated a specific practice or set of practices adopted in response to climate stressors (usually in combination with other sources of vulnerability) and then explored the causes behind their use and/or wider uptake over time. Of relevance was a review by Vermeulen et al (2018) that set out the concept of 'transformational' adaptation across 23 case studies.

Three key messages on scaling up emerged from the evidence. Firstly, planned adaptation should rely on complementarity and integration of strategies so that the underlying determinants of adoption, such as access to knowledge and information, exist alongside enabling factors, such as the endowment of productive assets, human capital (education and skills) and institutional support (for example, existence of farmer groups and collective action). Secondly, understanding the existing socio-economic conditions is essential to align planning to the expected impacts for different smallholder categories and to meet different groups' adaptive capacities. The barriers to adaptation relating to wealth and gender as well as to the dynamics of power and decision-making need to be considered to ensure equitable and inclusive development patterns. Finally, whilst it is not possible to identify common solutions that are applicable across all contexts, there are some recurrent features of sustained adaptation and scaling up. These include (i) integrated, multi-sectoral character of interventions, (ii) participatory approaches to planning, implementation, and dissemination, and (iii) fostering knowledge exchange and co-creation of knowledge. Institutional and social capital aspects were also important.

The evidence on knowledge management focused on the relative importance of either local knowledge and/or external, scientific knowledge on patterns of smallholder adaptation and how potential tensions stemming from inequitable 'politics of knowledge' can be solved. Several publications suggested that social learning, facilitated by one or more 'knowledge brokers', was a viable and effective solution. Learning platforms for multiple stakeholder interactions, including farmer field schools and similar practical demonstration training and other participatory communication solutions were also reviewed.

The way knowledge and information are produced, shared and transferred exerts a strong influence on individual as well as community adaptation patterns. Awareness of risks and cognisance of potential responses are important determinants of smallholders' willingness to pursue adaptation strategies. In addition, knowledge in the form of education, technical training, and skills transfer are the enabling factors that facilitate smallholders to adapt, i.e., it is a critical element of adaptive capacity building. For example, in 2010 a participatory rural appraisal exercise conducted by IFPRI in Kenya confirmed that farmers were aware of this link. Both men and women who were involved mentioned 'capacity building' defined as training, extension and information but also as support to formal and informal groups, as the most important resource needed for adaptation (Roncoli et al 2010). Similarly, a study in South Africa revealed that while media sources provide smallholders with information on climate change, such information on its own doesn't allow them to cope with change (Thinda et al 2020). Farmers identified the most critical adaptation constraint being a lack of access to extension and other advisory services that help them mediate and assimilate the relevant information. The lack of information on climate change coupled with a knowledge gap in coping strategies were also identified as critical constraints in Nigeria, Ghana and Pakistan (Popoola et al 2020).

Building adaptive capacity doesn't rely solely on external, scientific knowledge. Knowledge embedded in farmers' experience and tradition is also critically important to raise their awareness of climate risks and to select appropriate responses. The evidence confirmed that indigenous knowledge is an important source of inspiration for locally suitable practices and behaviours. Autonomous adaptation often occurs based on farmers' perception of climate change and variability. Local knowledge is fundamentally important for understanding and dealing with climate change, as farmers take measures primarily based on their perception. However, autonomous adaptations may be limited in scope and may be not effective in the long run (and even lead to maladaptation) as they respond to experienced threats and not to ongoing or projected changes (Akinyemi 2017, Makate 2019). Also, knowledge based on local practices may not be sufficient to prompt more transformative actions that account for inter-generational equity (Derbile et al 2016), or to embark into risky activities such as changing crop types and/or investing in irrigation (Etana et al 2020).

Bridging local and external knowledge is therefore critical as it broadens the farmers' knowledge base to include more forward-looking considerations (or, to induce proactive adaptation alongside reactive strategies, which may not always be sustainable in the long-term). The supply of scientific or external information, per se, doesn't imply that it is passed on, understood, and accepted; it depends on how it is communicated and if it matches smallholders' needs. Information and knowledge barriers are strongly linked with cognitive barriers (in fact, information is mediated and understood by each person's education and culture). For instance, different initial interpretations due to farmers having a shorter timeframe of perception compared to scientists, may lead to misunderstanding and persistent mistrust (Shackleton 2015, Etana et al 2020). To support long-term, sustainable adaptation, both local and external knowledge should be embraced within innovation processes (Shackleton 2015, Makate 2019).

Three key messages on knowledge management emerged from the evidence. Firstly, access to knowledge influences awareness of risks and cognisance of potential responses and is thus an important determinant of smallholders' willingness to pursue adaptation strategies. Knowledge in the form of education, technical training and skills transfer are also critical enabling factors for up taking adaptation in practice; when knowledge and information are transferred along more 'structured', one-way channels, communication solutions need to be both easily available (supplied) and accessible (farmers should be able to receive it, understand it and use it effectively). Secondly, local knowledge is fundamentally important for understanding and dealing with climate change. However, autonomous adaptations may be limited in scope and may not be effective in the long run. Knowledge based on local practices may not be sufficient to prompt more transformative action. Bridging local and external knowledge is thus critical because it widens the farmers' knowledge base to include more forward-looking considerations or, to induce 'proactive' adaptation alongside 'reactive' strategies. Finally, social learning (deep understanding and assimilation of concepts through social interaction) was reported to be an effective mechanism to link science, policy and practice to tackle multiple and related challenges of agricultural development, food security and climate change adaptation. Both formal groups and informal collective action can foster synergies for capacity building through social learning, but to ensure inclusion, social differentiation must be considered. Learning platforms based on participatory action research that bring together different actors have been shown to be particularly effective in supporting adaptation.

Whilst the evidence on scaling up and knowledge management often proposed a multi-sector approach and stressed the importance environmental considerations to secure equitable and sustainable adaptation, literature on the interactions between humans and ecosystems, or that using an environmental lens to discuss adaptation in smallholder agriculture, was sparse. This lack of evidence is nonetheless relevant since it highlights an important gap in knowledge. This nexus 'learning outcome' focuses on the extent to which human and environmental interactions have been explicitly considered in climate adaptation policies for smallholders as well as in intervention design, implementation and assessment. However, some issues did emerge, including the importance of farmers' social networks to adopt environmentally sustainable practices, the opportunities linked to ecosystem-based adaptation and the relevance and importance of adopting a 'landscape' approach. Smallholder farming is tightly coupled to local ecosystems and ecosystem goods and services (EGS) are the backbone for farmers livelihoods. Agriculturally based economies depend on healthy soils, water, forests and farm based EGS, including for example, fodder for animal feed or dung and fuel wood for energy supply. At the landscape level, forests protect farmland from erosion, protect the biodiversity of natural predators and contribute to watershed management securing water for productive and other uses (Adhikari et al 2018). To varying extents, all smallholders rely on these interactions between their farming activities with those of their surrounding environment. Common natural pool resources such as forests and wetlands also provide households with alternative or complementary sources of livelihoods and income and, more generally, a healthy and productive landscape encourages households to remain in rural areas, slowing down outward migration from the countryside whilst increasing income opportunities and sustaining local adaptation (FAO 2014, Arouna and Akpa 2019).

The interactions between small-scale farming and the environment may also have negative connotations. Farmers are exposed to natural disasters and weather extremes. On the other hand, even if smallholder agriculture does not contribute to water and air pollution as much as large-scale farm and livestock production, anthropogenic activities such as grazing, intensive farming, encroachment, and deforestation can severely undermine the natural resource base at local level and ultimately smallholders' livelihoods. In Zimbabwe, for instance, declining and erratic agricultural yields pose increasing pressure on the use of EGS from common natural resources pools (CNRP) such as wetlands and woodlands. These play an important role in sustaining livestock, agriculture (especially irrigation) and crop-livestock integration but also as a source of food security (wild fruits, vegetables) as well as alternative livelihoods and income (wood, crafts, medicines, especially for vulnerable households).

The progressive increase in these alternative uses (and increasing competition over their use) places these areas at risk, exacerbating the impacts of climate change and climate variability. Two CNRP pressures are emerging as a direct consequence of climate change, firstly, the areas of wetlands and woodlands are reducing, and secondly, the impacts of climate change are coming indirectly through the human system, with higher extraction rates and land use changes to expand cultivated and grazing areas (Chagumaira et al 2015). Despite these important interactions, the review identified only a few studies that explicitly investigated the links between smallholder agriculture and the ecosystem within the context of climate change adaptation. For example, El Chami et al (2020) explored the literature dealing with the contribution of sustainable agriculture to resilient agro-systems in the context of a changing climate. Although it didn't have a specific focus on human-environment nexus or NRM, it confirmed the limited relationships that exist between disciplines and the gaps in the literature. It showed that different management aspects were often studied separately, meaning that the literature has not considered sustainable agriculture as an entity but merely some practices and technologies that form part of sustainable agriculture, mainly through the improvement of system biodiversity and ecosystem services (El Chami et al 2020).

While the results from this review are of course influenced by the search strings and inclusion criteria, the paucity of sources on this topic also reflects a reality where policymaking and planning in agriculture, environment and climate change still occur in silos with limited exchange between different disciplines and practices. This is a key concern and should be recognised as a strategic development priority. Drawing on our evidence, three main areas of intervention can be identified that support a stronger integration of the nexus between human and ecological systems into adaptation planning, implementation, and assessment. Firstly, several studies call for a reframing smallholder farming and, more generally, agriculture, as an integrated system alongside natural resource management, energy, and climate change through a more holistic approach. Secondly, some evidence exists on the benefits as well as challenges of ecosystem-based adaptation to pursue more equitable and transformational adaptive strategies. Finally, social capital in the form of social networks and collective action are critical to achieving environmental outcomes; community-based adaptation must be supported, and adaptation should be addressed across different levels from the individual through the community up to the landscape scale. Farming has important inter-linked social, ecological, and technical systems which need to be recognised.

The constraints and challenges in the agricultural sector should be addressed holistically, considering food and energy production, environmental protection, and climate, water and waste management being interconnected and mutually dependent (Reid et al 2013). One key element to such a holistic and circular economy approach is the local dimension. In adaptation planning, this implies keeping local perspectives central both in the search for technological solutions and in policy agreements. For this to happen, it may be necessary to challenge the power imbalances and decision-making rules to ensure local people and organisations' needs (and possible solutions) are acknowledged by policymakers. Knowledge management and how information is produced, transferred, and used was highlighted as a key component and one which could shift current mindsets in policy, practice and research (Reid et al 2013).

The key messages on human-ecosystem nexus interactions that emerged from this review are summarised below. Firstly, there were few studies that explicitly investigated the links between smallholder agriculture and the ecosystem within the context of climate adaptation. A paucity of sources on this topic reflects the fact that policies in agriculture, environment and climate change still tend to be formulated in isolation with limited exchange between different disciplines and practices. Secondly, a transdisciplinary approach across the economic, social, and environmental domains with explicit integration of potential interventions at multiple levels, is needed. Farmers' social structures, and especially networks based around knowledgeable actors, or sustainability champions can often help achieve desired environmental outcomes at the local scale, and social capital in the form of collective action is also extremely important. Finally, to be transformative, actions undertaken at individual and community levels should find space and consistency in a higher-level framework that ultimately solves the trade-offs and barriers for longer-term, sustainable results. Beyond providing the enabling policy and legal environment (for example, land tenure, access rights for natural resources), external institutions (such as governmental and international organisations) can help integrate the three levels of intervention—household, community, and landscape—and, importantly, provide the right economic incentives to compensate smallholders for investments that don't deliver immediate returns, such as agroforestry.

Evidence reviews are generally best applied to studies where there is good primary data. However, this review was limited to assessing outputs from a wide range of climate change adaptation studies, all of which inevitably contained 'effect modifiers'. These included, for example, gender, levels of education and access to educational support, land tenure/access to land and other natural resources, or landscapes. There was also much heterogeneity in the resources included in this review: many studies were context-specific (village or landscape level) and their methodologies varied greatly. The heterogeneity was also due to the overall review question being disaggregated to cover the three inter-linked, yet quite different domains. This made it difficult to compare and aggregate results. To minimise bias, care was exercised in interpreting studies reporting climate change adaptation interventions across similar agricultural systems but conducted using different methodologies, as there was no single discriminator that could be used to determine which model/approach was best.

Potential limitations in comparing evidence stem from the variety and often inconsistent use of definitions. Burnham and Ma (2016) explored how literature has documented and conceptualised autonomous adaptation and reported a lack of conceptual clarity: multiple definitions of adaptation were used, and it was not always specified whether climate change referred to long-term variations, seasonal variations, or a combination. Many studies also differentiated conceptually between coping and adapting, and many included very different concepts under the 'adaptation' term with no clear definition of the temporal dimensions of both responses and stressors (Burnham and Ma 2016).

The review identified some important pitfalls for policy making in systematically transferring lessons into practice to support transformational adaptation in agriculture. Some barriers were financial, technical and/or of organisational nature, but others were more fundamental and will require a marked shift in how different stakeholders decision-making processes are framed and implemented. For adaptation pathways to be transformative and inclusive, the current policy making process must undergo change, including taking on a more holistic approach to address vulnerability as stemming from a complex web of causes, of which climate change is only one aspect. High-level policies should also build upon local experiential knowledge and priorities. However, there was a disconnection with insufficient coordination between policy, research and practice whereby smallholders' needs, and preferences are increasingly shaped by external actors. Mainstreaming successful local adaptation into large-scale planning requires participation, active stakeholder engagement, and devolution of rights and responsibilities. Methodological improvements are also needed to assess and evaluate adaptation outcomes as monitoring and evaluation is at the core of understanding and scaling up what works in practice. Stakeholder platforms can also provide a powerful tool alongside other analytical methods to encourage mutual learning, communication, and governance. Participatory research and experimentation are also needed to better understand and manage the trade-offs amongst competing objectives, and to better evaluate the social costs and benefits in the calculation of payment for ecosystem services and other economic incentives for farmers.

Finally, although our understanding of climate change adaption and the priorities for action in development programmes have become clearer in recent years, incorporating more explicit recognition of youth and gender, marginalised communities, and the value of local knowledge, the consensus on actions needed remains contested. This is because understanding the elements and interventions within smallholder agriculture and its need to adapt to climate change are non-linear, complex and interdependent; the implementation of interventions through investment programmes requires effective partnerships and concerted cooperation across multiple organizations and scales and hence the inherent difficulty in identifying clear 'lines of sight' between planned interventions and desired impacts (Tomic et al 2019).