Editing IPCC:AR6/SRCCL/Chapter-5 (section)

=== 5.6.4 Sustainable integrated agricultural systems ===

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A range of integrated agricultural systems are being tested to evaluate synergies between mitigation and adaptation and lead to low-carbon and climate-resilient pathways for sustainable food security and ecosystem health (robust evidence, medium agreement). Integration refers to the use of practices that enhance an agroecosystem’s mitigation, resilience, and sustainability functions. These systems follow holistic approaches with the objective of achieving biophysical, socio-cultural, and economic benefits from land management systems (Sanz et al. 2017 <sup>[[#fn:r1053|1053]]</sup> ). These integrated systems may include agroecology (FAO et al. 2018 <sup>[[#fn:r1054|1054]]</sup> ; Altieri et al. 2015 <sup>[[#fn:r1055|1055]]</sup> ), climate smart agriculture (FAO 2011c <sup>[[#fn:r1056|1056]]</sup> ; Lipper et al. 2014 <sup>[[#fn:r1057|1057]]</sup> ; Aggarwal et al. 2018 <sup>[[#fn:r1058|1058]]</sup> ), conservation agriculture (Aryal et al. 2016 <sup>[[#fn:r1059|1059]]</sup> ; Sapkota et al. 2015 <sup>[[#fn:r1060|1060]]</sup> ), and sustainable intensification (FAO 2011d <sup>[[#fn:r1061|1061]]</sup> ; Godfray 2015 <sup>[[#fn:r1062|1062]]</sup> ), amongst others.

Many of these systems are complementary in some of their practices, although they tend to be based on different narratives (Wezel et al. 2015 <sup>[[#fn:r1063|1063]]</sup> ; Lampkin et al. 2015 <sup>[[#fn:r1064|1064]]</sup> ; Pimbert 2015 <sup>[[#fn:r1065|1065]]</sup> ). They have been tested in various production systems around the world (Dinesh et al. 2017 <sup>[[#fn:r1066|1066]]</sup> ; Jat et al. 2016 <sup>[[#fn:r1067|1067]]</sup> ; Sapkota et al. 2015 <sup>[[#fn:r1068|1068]]</sup> and Neufeldt et al. 2013 <sup>[[#fn:r1069|1069]]</sup> ). Many technical innovations, for example, precision nutrient management (Sapkota et al. 2014 <sup>[[#fn:r1070|1070]]</sup> ) and precision water management (Jat et al. 2015 <sup>[[#fn:r1071|1071]]</sup> ), can lead to both adaptation and mitigation outcomes and even synergies; although negative adaptation and mitigation outcomes (i.e., trade-offs) are often overlooked. Adaptation potential of ecologically intensive systems includes crop diversification, maintaining local genetic diversity, animal integration, soil organic management, water conservation and harvesting the role of microbial assemblages (Section 5.3). Technical innovations may encompass not only inputs reduction, but complete redesign of agricultural systems (Altieri et al. 2017 <sup>[[#fn:r1072|1072]]</sup> ) and how knowledge is generated (Levidow et al. 2014 <sup>[[#fn:r1073|1073]]</sup> ), including social and political transformations.

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==== 5.6.4.1 Agroecology ====

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Agroecology (see Glossary) (Francis et al. 2003 <sup>[[#fn:r1074|1074]]</sup> ; Gliessman and Engles 2014 <sup>[[#fn:r1075|1075]]</sup> ; Gliessman 2018 <sup>[[#fn:r1076|1076]]</sup> ), provides knowledge for their design and management, including social, economic, political, and cultural dimensions (Dumont et al. 2016 <sup>[[#fn:r1077|1077]]</sup> ). It started with a focus at the farm level but has expanded to include the range of food system activities (Benkeblia 2018 <sup>[[#fn:r1078|1078]]</sup> ). Agroecology builds systems resilience through knowledge-intensive practices relying on traditional farming systems and co-generation of new insights and information with stakeholders through participatory action research (Menéndez et al. 2013 <sup>[[#fn:r1079|1079]]</sup> ). It provides a multidimensional view of food systems within ecosystems, building on ILK and co-evolving with the experiences of local people, available natural resources, access to these resources, and ability to share and pass on knowledge among communities and generations, emphasising the inter-relatedness of all agroecosystem components and the complex dynamics of ecological processes (Vandermeer 1995 <sup>[[#fn:r1080|1080]]</sup> ).

At the farm level, agroecological practices recycle biomass and regenerate soil biotic activities. They strive to attain balance in nutrient flows to secure favourable soil and plant growth conditions, minimise loss of water and nutrients, and improve use of solar radiation. Practices include efficient microclimate management, soil cover, appropriate planting time and genetic diversity. They seek to promote ecological processes and services such as nutrient cycling, balanced predator/prey interactions, competition, symbiosis, and successional changes. The overall goal is to benefit human and non-human communities in the ecological sphere, with fewer negative environmental or social impacts and fewer external inputs (Vandermeer et al. 1998 <sup>[[#fn:r1081|1081]]</sup> ; Altieri et al. 1998 <sup>[[#fn:r1082|1082]]</sup> ). From a food system focus, agroecology provides management options in terms of commercialisation and consumption through the promotion of short food chains and healthy diets (Pimbert and Lemke 2018 <sup>[[#fn:r1083|1083]]</sup> ; Loconto et al. 2018 <sup>[[#fn:r1084|1084]]</sup> ).

Agroecology has been proposed as a key set of practices in building climate resilience (FAO et al. 2018 <sup>[[#fn:r1085|1085]]</sup> ; Altieri et al. 2015 <sup>[[#fn:r1086|1086]]</sup> ). These can enhance on-farm diversity (of genes, species, and ecosystems) through a landscape approach (FAO 2018g <sup>[[#fn:r1087|1087]]</sup> ). Outcomes include soil conservation and restoration and thus soil carbon sequestration, reduction of the use of mineral and chemical fertilisers, watershed protection, promotion of local food systems, waste reduction, and fair access to healthy food through nutritious and diversified diets (Pimbert and Lemke 2018 <sup>[[#fn:r1088|1088]]</sup> ; Kremen et al. 2012 <sup>[[#fn:r1089|1089]]</sup> ; Goh 2011 <sup>[[#fn:r1090|1090]]</sup> ; Gliessman and Engles 2014 <sup>[[#fn:r1091|1091]]</sup> ).

A principle in agroecology is to contribute to food production by smallholder farmers (Altieri 2002 <sup>[[#fn:r1092|1092]]</sup> ). Since climatic events can severely impact smallholder farmers, there is a need to better understand the heterogeneity of small-scale agriculture in order to consider the diversity of strategies that traditional farmers have used and still use to deal with climatic variability. In Africa, many smallholder farmers cope with and even prepare for climate extremes, minimising crop failure through a series of agroecological practices (e.g., biodiversification, soil management, and water harvesting) (Mbow et al. 2014a <sup>[[#fn:r1093|1093]]</sup> ). Resilience to extreme climate events is also linked to on-farm biodiversity, a typical feature of traditional farming systems (Altieri and Nicholls 2017 <sup>[[#fn:r1094|1094]]</sup> ).

Critiques of agroecology refer to its explicit exclusion of modern biotechnology (Kershen 2013 <sup>[[#fn:r1095|1095]]</sup> ) and the assumption that smallholder farmers are a uniform unit with no heterogeneity in power (and thus gender) relationships (Neira and Montiel 2013 <sup>[[#fn:r1096|1096]]</sup> ; Siliprandi and Zuluaga Sánchez 2014 <sup>[[#fn:r1097|1097]]</sup> ).

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==== 5.6.4.2 Climate-smart agriculture ====

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‘Climate-smart agriculture’ (CSA) is an approach developed to tackle current food security and climate change challenges in a joint and synergistic fashion (Lipper et al. 2014 <sup>[[#fn:r1098|1098]]</sup> ; Aggarwal et al. 2018 <sup>[[#fn:r1099|1099]]</sup> ; FAO 2013c <sup>[[#fn:r1100|1100]]</sup> ). CSA is designed to be a pathway towards development and food security built on three pillars: increasing productivity and incomes, enhancing resilience of livelihoods and ecosystems and reducing, and removing GHG emissions from the atmosphere (FAO 2013c <sup>[[#fn:r1101|1101]]</sup> ). Climate-smart agricultural systems are integrated approaches to the closely linked challenges of food security, development, and climate change adaptation/mitigation to enable countries to identify options with maximum benefits and those where trade-offs need management.

Many agricultural practices and technologies already provide proven benefits to farmers’ food security, resilience and productivity (Dhanush and Vermeulen 2016 <sup>[[#fn:r1102|1102]]</sup> ). In many cases, these can be implemented by changing the suites of management practices. For example, enhancing soil organic matter to improve the water-holding capacity of agricultural landscapes also sequesters carbon. In annual cropping systems, changes from conventional tillage practices to minimum tillage can convert the system from one that either provides adaptation or mitigation benefits or neither to one that provides both adaptation and mitigation benefits (Sapkota et al. 2017a <sup>[[#fn:r1103|1103]]</sup> ; Harvey et al. 2014a <sup>[[#fn:r1104|1104]]</sup> ).

Increasing food production by using more fertilisers in agricultural fields could maintain crop yield in the face of climate change, but may result in greater overall GHG emissions. But increasing or maintaining the same level of yield by increasing nutrient-use- efficiency through adoption of better fertiliser management practices could contribute to both food security and climate change mitigation (Sapkota et al. 2017a <sup>[[#fn:r1105|1105]]</sup> ).

Mixed farming systems integrating crops, livestock, fisheries and agroforestry could maintain crop yield in the face of climate change, help the system to adapt to climatic risk, and minimise GHG emissions by increasingly improving the nutrient flow in the system (Mbow et al. 2014a <sup>[[#fn:r1106|1106]]</sup> ; Newaj et al. 2016 <sup>[[#fn:r1107|1107]]</sup> ; Bioversity International 2016 <sup>[[#fn:r1108|1108]]</sup> ). Such systems can help diversify production and/or incomes and support efficient and timely use of inputs, thus contributing to increased resilience, but they require local seed and input systems and extension services. Recent whole farm modelling exercises have shown the economic and environmental (reduced GH emissions, reduced land use) benefits of integrated crop-livestock systems (Gil et al. 2018 <sup>[[#fn:r1109|1109]]</sup> ) compared different soy-livestock systems across multiple economic and environmental indicators, including climate resilience. However, it is important to note that potential benefits are very context specific.

Although climate-smart agriculture involves a holistic approach, some argue that it narrowly focuses on technical aspects at the production level (Taylor 2018 <sup>[[#fn:r1110|1110]]</sup> ; Newell and Taylor 2018 <sup>[[#fn:r1111|1111]]</sup> ). Studying barriers to the adoption and diffusion of technological innovations for climate-smart agriculture in Europe, Long et al. (2016) <sup>[[#fn:r1112|1112]]</sup> found that there was incompatibility between existing policies and climate-smart agriculture objectives, including barriers to the adoption of technological innovations.

Climate-smart agricultural systems recognise that the implementation of the potential options will be shaped by specific country contexts and capacities, as well as enabled by access to better information, aligned policies, coordinated institutional arrangements and flexible incentives and financing mechanisms (Aggarwal et al. 2018 <sup>[[#fn:r1113|1113]]</sup> ). Attention to underlying socio-economic factors that affect adoption of practices and access to technologies is crucial for enhancing biophysical processes, increasing productivity, and reducing GHG emissions at scale. The Government of India, for example, has started a programme of climate resilient villages (CRV) as a learning platform to design, implement, evaluate and promote various climate-smart agricultural interventions, with the goal of ensuring enabling mechanisms at the community level (Srinivasa Rao et al. 2016 <sup>[[#fn:r1114|1114]]</sup> ).

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==== 5.6.4.3 Conservation agriculture ====

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Conservation agriculture (CA) is based on the principles of minimum soil disturbance and permanent soil cover, combined with appropriate crop rotation (Jat et al. 2014 <sup>[[#fn:r1115|1115]]</sup> ; FAO 2011e <sup>[[#fn:r1116|1116]]</sup> ). CA has been shown to respond with positive benefits to smallholder farmers under both economic and environmental pressures (Sapkota et al. 2017a, 2015 <sup>[[#fn:r1117|1117]]</sup> ). This agricultural production system uses a body of soil and residues management practices that control erosion (Blanco Sepúlveda <sup>[[#fn:r1118|1118]]</sup> and Aguilar Carrillo 2016) and at the same time improve soil quality, by increasing organic matter content and improving porosity, structural stability, infiltration and water retention (Sapkota et al. 2017a, 2015 <sup>[[#fn:r1119|1119]]</sup> and Govaerts et al. 2009).

Intensive agriculture during the second half of the 20th century led to soil degradation and loss of natural resources and contributed to climate change. Sustainable soil management practices can address both food security and climate change challenges faced by these agricultural systems. For example, sequestration of soil organic carbon (SOC) is an important strategy to improve soil quality and to mitigation of climate change (Lal 2004 <sup>[[#fn:r1120|1120]]</sup> ). CA has been reported to increase farm productivity by reducing costs of production (Aryal et al. 2015 <sup>[[#fn:r1121|1121]]</sup> ; Sapkota et al. 2015 <sup>[[#fn:r1122|1122]]</sup> ; Indoria et al. 2017 <sup>[[#fn:r1123|1123]]</sup> ) as well as to reduce GHG emission (Pratibha et al. 2016 <sup>[[#fn:r1124|1124]]</sup> ).

Conservation agriculture brings favourable changes in soil properties that affect the delivery of nature’s contribution to people (NCPs) or ecosystem services, including climate regulation through carbon sequestration and GHG emissions (Palm et al. 2013 <sup>[[#fn:r1125|1125]]</sup> ; Sapkota et al. 2017a <sup>[[#fn:r1126|1126]]</sup> ). However, by analysing datasets for soil carbon in the tropics, Powlson et al. (2014, 2016) argued that the rate of SOC increase and resulting GHG mitigation in CA systems, from zero-tillage in particular, has been overstated (Chapter 2).

However, there is unanimous agreement that the gain in SOC and its contribution to GHG mitigation by CA in any given soil is largely determined by the quantity of organic matter returned to the soil (Giller et al. 2009 <sup>[[#fn:r1127|1127]]</sup> ; Virto et al. 2011 <sup>[[#fn:r1128|1128]]</sup> ; Sapkota et al. 2017b <sup>[[#fn:r1129|1129]]</sup> ). Thus, a careful analysis of the production system is necessary to minimise the trade-offs among the multiple use of residues, especially where residues remain an integral part of livestock feeding (Sapkota et al. 2017b <sup>[[#fn:r1130|1130]]</sup> ). Similarly, replacing mono-cropping systems with more diversified cropping systems and agroforestry, as well as afforestation and deforestation, can buffer temperatures as well as increase carbon storage (Mbow et al. 2014a <sup>[[#fn:r1131|1131]]</sup> ; Bioversity International 2016 <sup>[[#fn:r1132|1132]]</sup> ), and provide diversified and healthy diets in the face of climate change.

Adoption of conservation agriculture in Africa has been low despite more than three decades of implementation (Giller et al. 2009 <sup>[[#fn:r1133|1133]]</sup> ), although there is promising uptake recently in east and southern Africa. This calls for a better understanding of the social and institutional aspects around CA adoption. Brown et al. (2017a) <sup>[[#fn:r1134|1134]]</sup> found that institutional and community constraints hampered the use of financial, physical, human and informational resources to implement CA programmes.

Gender plays an important role at the intra-household level in regard to decision-making and distributing benefits. Conservation agriculture interventions have implications for labour requirements, labour allocation, and investment decisions, all of which impact the roles of men and women (Farnworth et al. 2016 <sup>[[#fn:r1135|1135]]</sup> ) (Section 5.1.3). For example, in the Global South, CA generally reduces labour and production costs and generally leads to increased returns to family labour (Aryal et al. 2015 <sup>[[#fn:r1136|1136]]</sup> ) although a gender shift of the labour burden to women have also been described (Giller et al. 2009 <sup>[[#fn:r1137|1137]]</sup> ).

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==== 5.6.4.4 Sustainable intensification ====

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The need to produce about 50% more food by 2050, required to feed the increasing world population (FAO 2018a <sup>[[#fn:r1138|1138]]</sup> ), may come at the price of significant increases in GHG emissions and environmental impacts, including loss of biodiversity. For instance, land conversion for agriculture is responsible for an estimated 8–10% of all anthropogenic GHG emissions currently (Section 5.4). Recent calls for sustainable intensification (SI) are based on the premise that damage to the environment through extensification outweighs benefits of extra food produced on new lands (Godfray 2015 <sup>[[#fn:r1139|1139]]</sup> ). However, increasing the net production area by restoring already degraded land may contribute to increased production on the one hand and increased carbon sequestration on the other (Jat et al. 2016 <sup>[[#fn:r1140|1140]]</sup> ), thereby contributing to both increased agricultural production and improved natural capital outcomes (Pretty et al. 2018 <sup>[[#fn:r1141|1141]]</sup> ).

Sustainable intensification is a goal but does not specify ''a priori'' how it could be attained, for example, which agricultural techniques to deploy (Garnett et al. 2013 <sup>[[#fn:r1142|1142]]</sup> ). It can be combined with selected other improved management practices, for example, conservation agriculture (see above), or agroforestry, with additional economic, ecosystem services, and carbon benefits. Sustainable intensification, by improving nutrient, water, and other input-use efficiency, not only helps to close yield gaps and contribute to food security (Garnett et al. 2013 <sup>[[#fn:r1143|1143]]</sup> ), but also reduces the loss of such production inputs and associated emissions (Sapkota et al. 2017c <sup>[[#fn:r1144|1144]]</sup> ; Wollenberg et al. 2016 <sup>[[#fn:r1145|1145]]</sup> ). Closing yield gaps is a way to become more efficient in use of land per unit production. Currently, most regions in Africa and South Asia have attained less than 40% of their potential crop production (Pradhan et al. 2015 <sup>[[#fn:r1146|1146]]</sup> ). Integrated farming systems (e.g., mixed crop/livestock, crop/aquaculture) are strategies to produce more products per unit land, which in regard to food security, becomes highly relevant.

Sustainable intensification acknowledges that enhanced productivity needs to be accompanied by maintenance of other ecosystem services and enhanced resilience to shocks (Vanlauwe et al. 2014 <sup>[[#fn:r1147|1147]]</sup> ). SI in intensively farmed areas may require a reduction in production in favour of increasing sustainability in the broad sense (Buckwell et al. 2014 <sup>[[#fn:r1148|1148]]</sup> ) (Cross-Chapter Box 6 in Chapter 5). Hence, moving towards sustainability may imply lower yield growth rates than those maximally attainable in such situations. For areas that contain valuable natural ecosystems, such as the primary forest in the Congo basin, intensification of agriculture is one of the pillars of the strategy to conserve forest (Vanlauwe et al. 2014 <sup>[[#fn:r1149|1149]]</sup> ). Intensification in agriculture is recognised as one of the pathways to meet food security and climate change adaptation and mitigation goals (Sapkota et al. 2017c <sup>[[#fn:r1150|1150]]</sup> ).

However, SI does not always confer co-benefits in terms of food security and climate change adaption/mitigation. For example, in the case of Vietnam, intensified production of rice and pigs reduced GHG emissions in the short term through land sparing, but after two decades, the emissions associated with higher inputs were likely to outweigh the savings from land sparing (Thu Thuy et al. 2009). Intensification needs to be sustainable in all components of food system by curbing agricultural sprawl, rebuilding soils, restoring degraded lands, reducing agricultural pollution, increasing water use efficiency, and decreasing the use of external inputs (Cook et al. 2015 <sup>[[#fn:r1151|1151]]</sup> ).

A study conducted by Palm et al. (2010) <sup>[[#fn:r1152|1152]]</sup> in Sub-Saharan Africa, reported that, at low population densities and high land availability, food security and climate mitigation goals can be met with intensification scenarios, resulting in surplus crop area for reforestation. In contrast, for high population density and small farm sizes, attaining food security and reducing GHG emissions require the use of more mineral fertilisers to make land available for reforestation. However, some forms of intensification in drylands can increase rather than reduce vulnerability due to adverse effects such as environmental degradation and increased social inequity (Robinson et al. 2015 <sup>[[#fn:r1153|1153]]</sup> ).

Sustainable intensification has been critiqued for considering food security only from the supply side, whereas global food security requires attention to all aspects of food system, including access, utilisation, and stability (Godfray 2015 <sup>[[#fn:r1154|1154]]</sup> ). Further, adoption of high-input forms of agriculture under the guise of simultaneously improving yields and environmental performance will attract more investment leading to higher rate of adoption but with the environmental component of SI quickly abandoned (Godfray 2015 <sup>[[#fn:r1155|1155]]</sup> ). Where adopted, SI needs to engage with the sustainable development agenda to (i) identify SI agricultural practices that strengthen rural communities, improve smallholder livelihoods and employment, and avoid negative social and cultural impacts, including loss of land tenure and forced migration; (ii) invest in the social, financial, natural, and physical capital needed to facilitate SI implementation; and (iii) develop mechanisms to pay poor farmers for undertaking sustainability measures (e.g., GHG emissions mitigation or biodiversity protection) that may carry economic costs (Garnett et al. 2013 <sup>[[#fn:r1156|1156]]</sup> ).

In summary, integrated agricultural systems and practices can enhance food system resilience to climate change and reduce GHG emissions, while helping to achieve sustainability ( ''high confidence'' ).

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