If the side of a square is increased by 50 find the percent increase in its area

5.1.1

Food security and insecurity, the food system and climate change

The food system encompasses all the activities and actors in the production, transport, manufacturing, retailing, consumption, and waste of food, and their impacts on nutrition, health and well-being, and the environment [Figure 5.1].

Figure 5.1

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Interlinkages between the climate system, food system, ecosystems [land, water and oceans] and socio-economic system. These systems operate at multiple scales, both global and regional. Food security is an outcome of the food system leading to human well-being, which is also indirectly linked with climate and ecosystems through the socio-economic system. Adaptation measures can help […]

Interlinkages between the climate system, food system, ecosystems [land, water and oceans] and socio-economic system. These systems operate at multiple scales, both global and regional. Food security is an outcome of the food system leading to human well-being, which is also indirectly linked with climate and ecosystems through the socio-economic system. Adaptation measures can help to reduce negative impacts of climate change on the food system and ecosystems. Mitigation measures can reduce GHG emissions coming from the food system and ecosystems.

5.1.1.1

Food security as an outcome of the food system

The activities and the actors in the food system lead to outcomes such as food security and generate impacts on the environment. As part of the environmental impacts, food systems are a considerable contributor to GHG emissions, and thus climate change [Section 5.4]. In turn, climate change has complex interactions with food systems, leading to food insecurity through impacts on food availability, access, utilisation and stability [Table 5.1 and Section 5.2].

We take a food systems lens in the Special Report on Climate Change and Land [SRCCL] to recognise that demand for and supply of food are interlinked and need to be jointly assessed in order to identify the challenges of mitigation and adaptation to climate change. Outcomes cannot be disaggregated solely to, for example, agricultural production, because the demand for food shapes what is grown, where it is grown, and how much is grown. Thus, GHG emissions from agriculture result, in large part, from ‘pull’ from the demand side. Mitigation and adaptation involve modifying production, supply chain, and demand practices [through, for example, dietary choices, market incentives, and trade relationships], so as to evolve to a more sustainable and healthy food system.

According to FAO [2001a], food security is a situation that exists when all people, at all times, have physical, social, and economic access to sufficient, safe, and nutritious food that meets their dietary needs and food preferences for an active and healthy life. ‘All people at all times’ implies the need for equitable and stable food distribution, but it is increasingly recognised that it also covers the need for inter-generational equity, and therefore ‘sustainability’ in food production. ‘Safe and nutritious food … for a healthy life’ implies that food insecurity can occur if the diet is not nutritious, including when there is consumption of an excess of calories, or if food is not safe, meaning free from harmful substances.

A prime impact of food insecurity is malnourishment [literally ‘bad nourishment’] leading to malnutrition, which refers to deficiencies, excesses, or imbalances in a person’s intake of energy and/or nutrients. As defined by FAO et al. [2018], undernourishment occurs when an individual’s habitual food consumption is insufficient to provide the amount of dietary energy required to maintain a normal, active, healthy life. In addition to undernourishment in the sense of insufficient calories [‘hunger’], undernourishment occurs in terms of nutritional deficiencies in vitamins [e.g., vitamin A] and minerals [e.g., iron, zinc, iodine], so-called ‘hidden hunger’. Hidden hunger tends to be present in countries with high levels of undernourishment [Muthayya et al. 2013], but micronutrient deficiency can occur in societies with low prevalence of undernourishment. For example, in many parts of the world teenage girls suffer from iron deficiency [Whitfield et al. 2015] and calcium deficiency is common in Western-style diets [Aslam and Varani 2016]. Food security is related to nutrition, and conversely food insecurity is related to malnutrition. Not all malnourishment arises from food insecurity, as households may have access to healthy diets but choose to eat unhealthily, or it may arise from illness. However, in many parts of the world, poverty is linked to poor diets [FAO et al. 2018]. This may be through lack of resources to produce or access food in general, or healthy food, in particular, as healthier diets are more expensive than diets rich in calories but poor in nutrition [high confidence] [see meta-analysis by Darmon and Drewnowski 2015]. The relationship between poverty and poor diets may also be linked to unhealthy ‘food environments,’ with retail outlets in a locality only providing access to foods of low nutritional quality [Gamba et al. 2015] – such areas are sometimes termed ‘food deserts’ [Battersby 2012].

Whilst conceptually the definition of food security is clear, it is not straightforward to measure in a simple way that encompasses all its aspects. Although there are a range of methods to assess food insecurity, they all have some shortcomings. For example, the FAO has developed the Food Insecurity Experience Scale [FIES], a survey-based tool to measure the severity of overall households’ inability to access food. While it provides reliable estimates of the prevalence of food insecurity in a population, it does not reveal whether actual diets are adequate or not with respect to all aspects of nutrition [Section 5.1.2.1].

5.1.1.2

Effects of climate change on food security

Climate change is projected to negatively impact the four pillars of food security – availability, access, utilisation and stability – and their interactions [FAO et al. 2018] [high confidence]. This chapter assesses recent work since AR5 that has strengthened understanding of how climate change affects each of these pillars across the full range of food system activities [Table 5.1 and Section 5.2].

While most studies continue to focus on availability via impacts on food production, more studies are addressing related issues of access [e.g., impacts on food prices], utilisation [e.g., impacts on nutritional quality], and stability [e.g., impacts of increasing extreme events] as they are affected by a changing climate [Bailey et al. 2015]. Low-income producers and consumers are likely to be most affected because of a lack of resources to invest in adaptation and diversification measures [UNCCD 2017; Bailey et al. 2015].

Table 5.1

Relationships between food security, the food system, and climate change, and guide to chapter

5.1.2

Status of the food system, food insecurity and malnourishment

5.1.2.1

Trends in the global food system

Food is predominantly produced on land, with, on average, 83% of the 697 kg of food consumed per person per year, 93% of the 2884 kcal per day, and 80% of the 81 g of protein eaten per day coming from terrestrial production in 2013 [FAOSTAT 2018]. With increases in crop yields and production [Figure 5.2], the absolute supply of food has been increasing over the last five decades. Growth in production of animal-sourced food is driving crop utilisation for livestock feed [FAOSTAT 2018; Pradhan et al. 2013a]. Global trade of crop and animal-sourced food has increased by around 5 times between 1961 and 2013 [FAOSTAT 2018]. During this period, global food availability has increased from 2200 kcal/cap/day to 2884 kcal/cap/day, making a transition from a food deficit to a food surplus situation [FAOSTAT 2018; Hiç et al. 2016].

The availability of cereals, animal products, oil crops, and fruits and vegetables has mainly grown [FAOSTAT 2018], reflecting shifts towards more affluent diets. This, in general, has resulted in a decrease in prevalence of underweight and an increase in prevalence of overweight and obesity among adults [Abarca-Gómez et al. 2017]. During the period 1961–2016, anthropogenic GHG emissions associated with agricultural production has grown from 3.1 GtCO2-eq yr–1 to 5.8 GtCO2-eq yr–1 [Section 5.4.2 and Chapter 2]. The increase in emissions is mainly from the livestock sector [from enteric fermentation and manure left on pasture], use of synthetic fertiliser, and rice cultivation [FAOSTAT 201821].

Figure 5.2

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Global trends in [a] yields of maize, rice, and wheat [FAOSTAT 2018] – the top three crops grown in the world; [b] production of crop and animal calories and use of crop calories as livestock feed [FAOSTAT 2018]; [c] production from marine and aquaculture fisheries [FishStat 2019]; [e] food trade in calories [FAOSTAT 2018]; [f] […]

Global trends in [a] yields of maize, rice, and wheat [FAOSTAT 2018] – the top three crops grown in the world; [b] production of crop and animal calories and use of crop calories as livestock feed [FAOSTAT 2018]; [c] production from marine and aquaculture fisheries [FishStat 2019]; [e] food trade in calories [FAOSTAT 2018]; [f] food supply and required food [i.e., based on human energy requirements for medium physical activities] from 1961–2012 [FAOSTAT 2018; Hiç et al. 2016]; [g] prevalence of overweight, obesity and underweight from 1975–2015 [Abarca-Gómez et al. 2017]; and [h] GHG emissions for the agriculture sector, excluding land-use change [FAOSTAT 2018]. For figures [b] and [e], data provided in mass units were converted into calories using nutritive factors [FAO 2001b]. Data on emissions due to burning of savanna and cultivation of organic soils is provided only after 1990 [FAOSTAT 2018].

5.1.2.2

Food insecurity status and trends

In addressing food security the dual aspects of malnutrition – under-nutrition and micro-nutrient deficiency, as well as over-consumption, overweight, and obesity – need to be considered [Figure 5.2 [g] and Table 5.2]. The UN agencies’ State of Food Security and Nutrition 2018 report [FAO et al. 2018] and the Global Nutrition Report 2017 [Development Initiatives 2017] summarise the global data. The State of Food Security report’s estimate for undernourished people on a global basis is 821 million, up from 815 million the previous year and 784 million the year before that. Previous to 2014/2015 the prevalence of hunger had been declining over the last three decades. The proportion of young children [under five] who are stunted [low height-for-age], has been gradually declining, and was 22% in 2017 compared to 31% in 2012 [150.8 million, down from 165.2 million in 2012]. In 2017, 50.5 million children [7.5%] under five were wasted [low weight-for-height]. Since 2014, undernutrition has worsened, particularly in parts of Sub-Saharan Africa, south-eastern Asia and Western Asia, and recently Latin America. Deteriorations have been observed most notably in situations of conflict and conflict combined with droughts or floods [FAO et al. 2018].

Regarding micronutrient deficiencies known as ‘hidden hunger’, reporting suggests a prevalence of one in three people globally [FAO 2013a; von Grebmer et al. 2014; Tulchinsky 2010] [Table 5.2]. In the last decades, hidden hunger [measured through proxies targeting iron, vitamin A, and zinc deficiencies] worsened in Africa, while it mainly improved in the Asia and Pacific regions [Ruel-Bergeron et al. 2015]. In 2016, 613 million women and girls aged 15 to 49 suffered from iron deficiency [Development Initiatives 2018]; in 2013, 28.5% of the global population suffered from iodine deficiency; and in 2005, 33.3% of children under five and 15.3% of pregnant women suffered from vitamin A deficiency, and 17.3% of the global population suffered from zinc deficiency [HLPE 2017].

Globally, as the availability of inexpensive calories from commodity crops increases, so does per capita consumption of calorie-dense foods [Ng et al. 2014; NCD-RisC 2016a; Abarca-Gómez et al. 2017 and Doak and Popkin 2017]. As a result, in every region of the world, the prevalence of obesity [body mass index >30 kg m–2] and overweight [body mass index range between normality [18.5–24.9] and obesity] is increasing. There are now more obese adults in the world than underweight adults [Ng et al. 2014; NCD-RisC 2016a; Abarca-Gómez et al. 2017 and Doak and Popkin 2017]. In 2016, around two billion adults were overweight, including 678 million suffering from obesity [NCD-RisC 2016a; Abarca-Gómez et al. 2017]. The prevalence of overweight and obesity has been observed in all age groups.

Around 41 million children under five years and 340 million children and adolescents aged 5–19 years were suffering from overweight or obesity in 2016 [NCD-RisC 2016a; FAO et al. 2017; WHO 2015]. In many high-income countries, the rising trends in children and adolescents suffering from overweight or obesity have stagnated at high levels; however, these have accelerated in parts of Asia and have very slightly reduced in European and Central Asian lower and middle-income countries [Abarca-Gómez et al. 2017; Doak and Popkin 2017; Christmann et al. 2009].

There are associations between obesity and non-communicable diseases such as diabetes, dementia, inflammatory diseases [Saltiel and Olefsky 2017], cardiovascular disease [Ortega et al. 2016] and some cancers, for example, of the colon, kidney, and liver [Moley and Colditz 2016]. There is a growing recognition of the rapid rise in overweight and obesity on a global basis and its associated health burden created through non-communicable diseases [NCD-RisC 2016a; HLPE 2017].

Analyses reported in FAO et al. [2018] highlight the link between food insecurity, as measured by the FIES scale, and malnourishment [medium agreement, robust evidence]. This varies by malnourishment measure as well as country [FAO et al. 2018]. For example, there is limited evidence [low agreement but multiple studies] that food insecurity and childhood wasting [i.e., or low weight for height] are closely related, but it is very likely [high agreement, robust evidence] that childhood stunting and food insecurity are related [FAO et al. 2018]. With respect to adult obesity there is robust evidence, with medium agreement, that food insecurity, arising from poverty reducing access to nutritious diets, is related to the prevalence of obesity, especially in high-income countries and adult females. An additional meta-analysis [for studies in Europe and North America] also finds a negative relationship between income and obesity, with some support for an effect of obesity causing low income [as well as vice versa] [Kim and von dem Knesebeck 2018].

As discussed in Section 5.1.1.1, different methods of assessing food insecurity can provide differential pictures. Of particular note is the spatial distribution of food insecurity, especially in higher-income countries. FAO et al. [2018] reports FIES estimates of severe food insecurity in Africa, Asia and Latin America of 29.8%, 6.9% and 9.8% of the population, respectively, but of 1.4% of the population [i.e., about 20 million in total; pro rata 40% relative to those in 2010; and India [Green et al. 2017; Vetter et al. 2017], where alternative diet scenarios can affect emissions from the food system by –20 to +15%.

Springmann et al.[2018a] modelled the role of technology, waste reduction and dietary change in living within planetary boundaries [Rockström et al. 2009], with the climate change boundary being a 66% chance of limiting warming to less than 2°C. They found that all are necessary for the achievement of a sustainable food system. Their principal conclusion is that only by adopting a ‘flexitarian diet’, as a global average, would climate change be limited to under two degrees. Their definition of a flexitarian diet is fruits and vegetables, plant-based proteins, modest amounts of animal-based proteins, and limited amounts of red meat, refined sugar, saturated fats, and starchy foods.

Healthy and sustainable diets address both health and environmental concerns [Springmann et al. 2018b]. There is high agreement that there are significant opportunities to achieve both objectives simultaneously. Contrasting results of marginal GHG emissions, that is, variations in emissions as a result of variation in one or more dietary components, are found when comparing low to high emissions in self-selected diets [diets freely chosen by consumers]. Vieux et al. [2013] found self-selected healthier diets with higher amounts of plant-based food products did not result in lower emissions, while [Rose et al. 2019] found that the lowest emission diets analysed were lower in meat but higher in oil, refined grains and added sugar. Vieux et al. [2018] concluded that setting nutritional goals with no consideration for the environment may increase GHG emissions.

Tukker et al. [2011] also found a slight increase in emissions by shifting diets towards the European dietary guidelines, even with lower meat consumption. Heller and Keoleian [2015] found a 12% increase in GHG emissons when shifting to iso-caloric diets, defined as diets with the same caloric intake of diets currently consumed, following the USA guidelines and a 1% decrease in GHG emissions when adjusting caloric intake to recommended levels for moderate activity. There is scarce information on the marginal GHG emissions that would be associated with following dietary guidelines in developing countries.

Some studies have found a modest mitigation potential of diet shifts when economic and biophysical systems effects are taken into account in association with current dietary guidelines. Tukker et al. [2011], considering economic rebound effects of diet shifts [i.e., part of the gains would be lost due to increased use at lower prices], found maximum changes in emissions of the EU food system of 8% [less than 2% of total EU emissions] when reducing meat consumption by 40 to 58%. Using an economic optimisation model for studying carbon taxation in food but with adjustments of agricultural production systems and commodity markets in Europe, Zech and Schneider [2019] found a reduction of 0.41% in GHG emissions at a tax level of 50 USD per tCO2-eq. They estimate a leakage of 43% of the GHG emissions reduced by domestic consumption, [i.e., although reducing emissions due to reducing consumption, around 43% of the emissions would not be reduced because part of the production would be directed to exports].

Studying optimised beef production systems intensification technologies in a scenario of no grasslands area expansion de Oliveira Silva et al. [2016] found marginal GHG emissions to be negligible in response to beef demand in the Brazilian Cerrado. This was because reducing productivity would lead to increased emission intensities, cancelling out the effect of reduced consumption.

In summary, there is significant potential mitigation [high confidence] arising from the adoption of diets in line with dietary recommendations made on the basis of health. These are broadly similar across most countries. These are typically capped at the number of calories and higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts and seeds, and lower in animal-sourced foods, fats and sugar. Such diets have the potential to be both more sustainable and healthier than alternative diets [but healthy diets are not necessarily sustainable and vice versa]. The extent to which the mitigation potential of dietary choices can be realised requires both climate change and health being considered together. Socio-economic [prices, rebound effects], political, and cultural contexts would require significant consideration to enable this mitigation potential to be realised.

5.6.4

Sustainable integrated agricultural systems

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]. These integrated systems may include agroecology [FAO et al. 2018; Altieri et al. 2015], climate smart agriculture [FAO 2011c; Lipper et al. 2014; Aggarwal et al. 2018], conservation agriculture [Aryal et al. 2016; Sapkota et al. 2015], and sustainable intensification [FAO 2011d; Godfray 2015], 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; Lampkin et al. 2015; Pimbert 2015]. They have been tested in various production systems around the world [Dinesh et al. 2017; Jat et al. 2016; Sapkota et al. 2015 and Neufeldt et al. 2013]. Many technical innovations, for example, precision nutrient management [Sapkota et al. 2014] and precision water management [Jat et al. 2015], 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] and how knowledge is generated [Levidow et al. 2014], including social and political transformations.

5.6.4.1

Agroecology

Agroecology [see Glossary] [Francis et al. 2003; Gliessman and Engles 2014; Gliessman 2018], provides knowledge for their design and management, including social, economic, political, and cultural dimensions [Dumont et al. 2016]. It started with a focus at the farm level but has expanded to include the range of food system activities [Benkeblia 2018]. 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]. 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].

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; Altieri et al. 1998]. 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; Loconto et al. 2018].

Agroecology has been proposed as a key set of practices in building climate resilience [FAO et al. 2018; Altieri et al. 2015]. These can enhance on-farm diversity [of genes, species, and ecosystems] through a landscape approach [FAO 2018g]. 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; Kremen et al. 2012; Goh 2011; Gliessman and Engles 2014].

A principle in agroecology is to contribute to food production by smallholder farmers [Altieri 2002]. 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]. Resilience to extreme climate events is also linked to on-farm biodiversity, a typical feature of traditional farming systems [Altieri and Nicholls 2017].

Critiques of agroecology refer to its explicit exclusion of modern biotechnology [Kershen 2013] and the assumption that smallholder farmers are a uniform unit with no heterogeneity in power [and thus gender] relationships [Neira and Montiel 2013; Siliprandi and Zuluaga Sánchez 2014].

5.6.4.2

Climate-smart agriculture

‘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; Aggarwal et al. 2018; FAO 2013c]. 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]. 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]. 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; Harvey et al. 2014a].

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].

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; Newaj et al. 2016; Bioversity International 2016]. 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] 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; Newell and Taylor 2018]. Studying barriers to the adoption and diffusion of technological innovations for climate-smart agriculture in Europe, Long et al. [2016] 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]. 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].

5.6.4.3

Conservation agriculture

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; FAO 2011e]. CA has been shown to respond with positive benefits to smallholder farmers under both economic and environmental pressures [Sapkota et al. 2017a, 2015]. This agricultural production system uses a body of soil and residues management practices that control erosion [Blanco Sepúlveda 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 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]. CA has been reported to increase farm productivity by reducing costs of production [Aryal et al. 2015; Sapkota et al. 2015; Indoria et al. 2017] as well as to reduce GHG emission [Pratibha et al. 2016].

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; Sapkota et al. 2017a]. 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; Virto et al. 2011; Sapkota et al. 2017b]. 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]. 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; Bioversity International 2016], 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], 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] 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] [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] although a gender shift of the labour burden to women have also been described [Giller et al. 2009].

5.6.4.4

Sustainable intensification

The need to produce about 50% more food by 2050, required to feed the increasing world population [FAO 2018a], 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]. 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], thereby contributing to both increased agricultural production and improved natural capital outcomes [Pretty et al. 2018].

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]. 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], but also reduces the loss of such production inputs and associated emissions [Sapkota et al. 2017c; Wollenberg et al. 2016]. 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]. 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]. SI in intensively farmed areas may require a reduction in production in favour of increasing sustainability in the broad sense [Buckwell et al. 2014] [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]. 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].

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].

A study conducted by Palm et al. [2010] 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].

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]. 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]. 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].

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].

CCB6

Agricultural intensification: Land sparing, land sharing and sustainability

Eamon Haughey [Ireland], Tim Benton [United Kingdom], Annette Cowie [Australia], Lennart Olsson [Sweden], Pete Smith [United Kingdom]

Introduction

The projected demand for more food, fuel and fibre for a growing human population necessitates intensification of current land use to avoid conversion of additional land to agriculture and potentially allow the sparing of land to provide other ecosystem services, including carbon sequestration, production of biomass for energy, and the protection of biodiversity [Benton et al. 2018; Garnett et al. 2013]. Land-use intensity may be defined in terms of three components; [i] intensity of system inputs [land/soil, capital, labour, knowledge, nutrients and other chemicals], [ii] intensity of system outputs [yield per unit land area or per specific input] and [iii] the impacts of land use on ecosystem services such as changes in soil carbon or biodiversity [Erb et al. 2013]. Intensified land use can lead to ecological damage as well as degradation of soil, resulting in a loss of function which underpins many ecosystem services [Wilhelm and Smith 2018; Smith et al. 2016]. Therefore, there is a risk that increased agricultural intensification could deliver short-term production goals at the expense of future productive potential, jeopardising long term food security [Tilman et al. 2011].

Agroecosystems which maintain or improve the natural and human capital and services they provide may be defined as sustainable systems, while those which deplete these assets as unsustainable [Pretty and Bharucha 2014]. Producing more food, fuel and fibre without the conversion of additional non-agricultural land while simultaneously reducing environmental impacts requires what has been termed sustainable intensification [Godfray et al. 2010; FAO 2011e] [Glossary and Figure 1 in this Cross-Chapter Box]. Sustainable intensification [SI] may be achieved through a wide variety of means; from improved nutrient and water use efficiency via plant and animal breeding programmes, to the implementation of integrated soil fertility and pest management practices, as well as by smarter land-use allocation at a larger spatial scale: for example, matching land use to the context and specific capabilities of the land [Benton et al. 2018]. However, implementation of SI is broader than simply increasing the technical efficiency of agriculture [‘doing more with less’]. It sometimes may require a reduction of yields to raise sustainability, and successful implementation can be dependent on place and scale. Pretty et al. [2018], following Hill [1985], highlights three elements to SI: [i] increasing efficiency, [ii] substitution of less beneficial or efficient practices for better ones, and [iii] system redesign to adopt new practices and farming systems [Table 1 in this Cross-Chapter Box].

Under a land sparing strategy, intensification of land use in some areas, generating higher productivity per unit area of land, can allow other land to provide other ecosystem services, such as increased carbon sequestration and the conservation of natural ecosystems and biodiversity [Balmford et al. 2018 and Strassburg et al. 2014]. Conversely under a land sharing strategy, less, or no, land is set aside, but lower levels of intensification are applied to agricultural land, providing a combination of provisioning and other functions such as biodiversity conservation from the same land [Green et al. 2005]. The two approaches are not mutually exclusive and the suitability of their application is generally system-, scale- and/or location-specific [Fischer et al. 2014]. One crucial issue for the success of a land sparing strategy is that spared land is protected from further conversion. As the profits from the intensively managed land increase, there is an incentive for conversion of additional land for production [Byerlee et al. 2014]. Furthermore, it is implicit that there are limits to the SI of land at a local and also planetary boundary level [Rockström et al. 2009]. These may relate to the ‘health’ of soil, the presence of supporting services, such as pollination, local limits to water availability, or limits on air quality. This implies that it may not be possible to meet demand ‘sustainably’ if demand exceeds local and global limits. There are no single global solutions to these challenges and specific in situ responses for different farming systems and locations are required. Bajželj et al. [2014] showed that implementation of SI, primarily through yield gap closure, had better environmental outcomes compared with ‘business as usual’ trajectories. However, SI alone will not be able to deliver the necessary environmental outcomes from the food system – dietary change and reduced food waste are also required [Springmann et al. 2018a; Bajželj et al. 2014].

Cross-Chapter Box 6, Table 1 | Approaches to sustainable intensification of agriculture [Pretty et al. 2018; Hill 1985].

ApproachSub-categoryExamples/notesImproving efficiencyPrecision agricultureHigh- and low-technology options to optimise resource use.Genetic improvementsImproved resource use efficiency through crop or livestock breeding.Irrigation technologyIncreased production in areas currently limited by precipitation [sustainable water supply required].Organisational scale-upIncreasing farm organisational scale [e.g., cooperative schemes] can increase efficiency via facilitation of mechanisation and precision techniques.SubstitutionGreen fertiliserReplacing chemical fertiliser with green manures, compost [including vermicompost], biosolids and digestate [by-product of anaerobic digestion] to maintain and improve soil fertility.Biological controlPest control through encouraging natural predators.Alternative cropsReplacment of annual with perennial crops reducing the need for soil disturbance and reducing erosion.Premium productsIncrease farm-level income for less output by producing a premium product.System redesignSystem diversificationImplementation of alternative farming systems: organic, agroforestry and intercropping [including the use of legumes].Pest managementImplementing integrated pest and weed management to reduce the quantities of inputs required.Nutrient managementImplementing integrated nutrient management by using crop and soil specific nutrient management – guided by soil testing.Knowledge transferUsing knowledge sharing and technology platforms to accelerate the uptake of good agricultural practices.

Improved efficiency – example of precision agriculture

Precision farming usually refers to optimising production in fields through site-specific choices of crop varieties, agrochemical application, precise water management [e.g., in given areas or threshold moistures] and management of crops at a small scale [or livestock as individuals] [Hedley 2015]. Precision agriculture has the potential to achieve higher yields in a more efficient and sustainable manner compared with traditional low-precision methods.

Precision agriculture

Precision agriculture is a technologically advanced approach that uses continual monitoring of crop and livestock performance to actively inform management practices. Precise monitoring of crop performance over the course of the growing season will enable farmers to economise on their inputs in terms of water, nutrients and pest management. Therefore, it can contribute to both the food security [by maintaining yields], sustainability [by reducing unnecessary inputs] and land sparing goals associated with SI. The site-specific management of weeds allows a more efficient application of herbicide to specific weed patches within crops [Jensen et al. 2012]. Such precision weed control has resulted in herbicide savings of 19–22% for winter oilseed rape, 46–57% for sugar beet and 60–77% for winter wheat production [Gutjahr and Gerhards 2010]. The use of on-farm sensors for real time management of crop and livestock performance can enhance farm efficiency [Aqeel-Ur-Rehman et al. 2014]. Mapping soil nutrition status can allow for more targeted, and therefore more effective, nutrient management practices [Hedley 2015]. Using wireless sensors to monitor environmental conditions, such as soil moisture, has the potential to allow more efficient crop irrigation [Srbinovska et al. 2015]. Controlled traffic farming, where farm machinery is confined to permanent tracks, using automatic steering and satellite guidance, increases yields by minimising soil compaction. However, barriers to the uptake of many of these high-tech precision agriculture technologies remain. In what is described as the ‘implementation problem’, despite the potential to collect vast quantities of data on crop or livestock performance, applying these data to inform management decisions remains a challenge [Lindblom et al. 2017].

Low-tech precision agriculture

The principle of precision agriculture can be applied equally to low capital-input farming, in the form of low-tech precision agriculture [Conway 2013]. The principle is the same, but instead of adopting capital-heavy equipment [such as sensor technology connected to the ‘internet of things’, or large machinery and expensive inputs], farmers use knowledge and experience and re-purposed innovative approaches, such as a bottle cap as a fertiliser measure for each plant, applied by hand [Mondal and Basu 2009]. This type of precision agriculture is particularly relevant to small-scale farming in the Global South, where capital investment is major limiting factor. For example, the application of a simple seed priming technique resulted in a 20 to 30% increase in yields of pearl millet and sorghum in semi-arid West Africa [Aune et al. 2017]. Low-tech precision agriculture has the potential to increase the economic return per unit land area while also creating new employment opportunities.

Cross Chapter Box 6 Figure 1

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There is a need to balance increasing demands for food, fuel and fibre with long-term sustainability of land use.Sustainable intensification can, in theory, offer a window of opportunity for the intensification of land use without causing degradation. This potentially allows the sparing of land to provide other ecosystem services, including carbon sequestration and the protection […]

There is a need to balance increasing demands for food, fuel and fibre with long-term sustainability of land use.Sustainable intensification can, in theory, offer a window of opportunity for the intensification of land use without causing degradation. This potentially allows the sparing of land to provide other ecosystem services, including carbon sequestration and the protection of biodiversity. However, the potential for SI is system specific and may change through time [indicated by grey arrows]. Current practice may already be outside of this window and be unsustainable in terms of negative impacts on the long-term sustainability of the system.

Sustainable intensification through farming system redesign

Sustainable intensification requires equal weight to be placed on the sustainability and intensification components [Benton 2016; Garnett et al. 2013]. Figure 1 in this Cross-Chapter Box outlines the trade-offs which SI necessitates between the intensity of land use against long-term sustainability. One approach to this challenge is through farming system redesign, including increased diversification.

Diversification of intensively managed systems

Incorporating higher levels of plant diversity in agroecosystems can improve the sustainability of farming systems [Isbell et al. 2017]. Where intensive land use has led to land degradation, more diverse land-use systems, such as intercropping, can provide a more sustainable land-use option with co-benefits for food security, adaptation and mitigation objectives. For example, in temperate regions, highly productive agricultural grasslands used to produce meat and dairy products are characterised by monoculture pastures with high agrochemical inputs. Multi-species grasslands may provide a route to SI, as even a modest increase in species richness in intensively managed grasslands can result in higher forage yields without increased inputs, such as chemical fertiliser [Finn et al. 2013; Sanderson et al. 2013; Tilman et al. 2011]. Recent evidence also indicates multispecies grasslands have greater resilience to drought, indicating co-benefits for adaptation [Hofer et al. 2016; Haughey et al. 2018].

Diversification of production systems

Agroforestry systems [see Glossary] can promote regional food security and provide many additional ecosystem services when compared with monoculture crop systems. Co-benefits for mitigation and adaptation include increased carbon sequestration in soils and biomass, improved water and nutrient use efficiency and the creation of favourable micro-climates [Waldron et al. 2017]. Silvopasture systems, which combine grazing of livestock and forestry, are particularly useful in reducing land degradation where the risk of soil erosion is high [Murgueitio et al. 2011]. Crop and livestock systems can also be combined to provide multiple services. Perennial wheat derivatives produced both high quality forage and substantial volumes of cereal grains [Newell and Hayes 2017], and show promise for integrating cereal and livestock production while sequestering soil carbon [Ryan et al. 2018]. A key feature of diverse production systems is the provision of multiple income streams for farming households, providing much needed economic resilience in the face of fluctuation of crop yields and prices.

Landscape approaches

The land sparing and land sharing approaches which may be used to implement SI are inherently ‘landscape approaches’ [e.g., Hodgson et al. 2010]. While the term landscape is by no means precise [Englund et al. 2017], landscape approaches, focused, for example, at catchment scale, are generally agreed to be the best way to tackle competing demands for land [e.g., Sayer et al. 2013], and are the appropriate scale at which to focus the implementation of sustainable intensification. The landscape approach allots land to various uses – cropping, intensive and extensive grazing, forestry, mining, conservation, recreation, urban, industry, infrastructure – through a planning process that seeks to balance conservation and production objectives. With respect to SI, a landscape approach is pertinent to achieving potential benefits for biodiversity conservation, ensuring that land ‘spared’ through SI remains protected, and that adverse impacts of agriculture on conservation land are minimised. Depending on the land governance mechanisms applied in the jurisdiction, different approaches will be appropriate/required. However, benefits are only assured if land-use restrictions are devised and enforced.

Summary

Intensification needs to be achieved sustainably, necessitating a balance between productivity today and future potential [high agreement, medium evidence]. Improving the efficiency of agriculture systems can increase production per unit of land through more effective resource use. To achieve SI, some intensively managed agricultural systems may have to be diversified as they cannot be further intensified without land degradation. A combination of land sparing and sharing options can be utilised to achieve SI – their application is most likely to succeed if applied using a landscape approach.

5.6.5

Role of urban agriculture

Cities are an important actor in the food system through demand for food by urban dwellers and production of food in urban and peri-urban areas [Cross-Chapter Box 4 in Chapter 2]. Both the demand side and supply side roles are important relative to climate change mitigation and adaptation strategies. Urban areas are home to more than half of the world’s population, and a minimal proportion of the production. Thus, they are important drivers for the development of the complex food systems in place today, especially with regard to supply chains and dietary preferences.

The increasing separation of urban and rural populations with regard to territory and culture is one of the factors favouring the nutrition transition towards urban diets [Weber and Matthews 2008; Neira et al. 2016]. These are primarily based on a high diversity of food products, independent of season and local production, and on the extension of the distances that food travels between production and consumption. The transition of traditional diets to more homogeneous diets has also become tied to consumption of animal protein, which has increased GHG emissions globally [Section 5.4.6].

Cities are becoming key actors in developing strategies of mitigation to climate change, in their food procurement and in sustainable urban food policies alike [McPhearson et al. 2018]. These are being developed by big and medium-sized cities in the world, often integrated within climate change policies [Moragues et al. 2013 and Calori and Magarini 2015]. A review of 100 cities shows that urban food consumption is one of the largest sources of urban material flows, urban carbon footprint, and land footprint [Goldstein et al. 2017]. Additionally, the urban poor have limited capacity to adapt to climate-related impacts, which place their food security at risk under climate change [Dubbeling and de Zeeuw 2011].

Urban and peri-urban areas. In 2010, around 14% of the global population was nourished by food grown in urban and peri-urban areas [Kriewald et al. 2019]. A review study on Sub-Saharan Africa shows that urban and peri-urban agriculture contributes to climate change adaptation and mitigation [Lwasa et al. 2014, 2015]. Urban and peri-urban agriculture reduces the food carbon footprint by avoiding long distance food transport. These types of agriculture also limit GHG emissions by recycling organic waste and wastewater that would otherwise release methane from landfills and dumping sites [Lwasa et al. 2014]. Urban and peri-urban agriculture also contribute in adapting to climate change, including extreme events, by reducing the urban heat island effect, increasing water infiltration and slowing down run-offs to prevent flooding, etc. [Lwasa et al. 2014, 2015; Kumar et al. 2017a]. For example, a scenario analysis shows that urban gardens reduce the surface temperature up to 10°C in comparison to the temperature without vegetation [Tsilini et al. 2015]. Urban agriculture can also improve biodiversity and strengthen associated ecosystem services [Lin et al. 2015].

Urban and peri-urban agriculture is exposed to climate risks and urban growth that may undermine its long-term potential to address urban food security [Padgham et al. 2015]. Therefore, there is a need to better understand the impact of urban sprawl on peri-urban agriculture; the contribution of urban and peri-urban agriculture to food self-sufficiency of cities; the risks posed by pollutants from urban areas to agriculture and vice-versa; the global and regional extent of urban agriculture; and the role that urban agriculture could play in climate resilience and abating malnutrition [Mok et al. 2014; Hamilton et al. 2014]. Globally, urban sprawl is projected to consume 1.8–2.4% and 5% of the current cultivated land by 2030 and 2050 respectively, leading to crop calorie loss of 3–4% and 6–7%, respectively [Pradhan et al. 2014 and Bren d’Amour et al. 2017]. Kriewald et al. 2019 shows that the urban growth has the largest impact in many sub-continental regions [e.g., Western, Central, and Eastern Africa], while climate change will mostly reduce potential of urban and peri-urban agriculture in Southern Europe and North Africa.

In summary, urban and peri-urban agriculture can contribute to improving urban food security, reducing GHG emissions, and adapting to climate change impacts [robust evidence, medium agreement].

5.6.6

Links to the Sustainable Development Goals

In 2015, the Sustainable Development Goals [SDGs] and the Paris Agreement were two global major international policies adopted by all countries to guide the world to overall sustainability, within the 2030 Sustainable Development Agenda and UNFCCC processes respectively. The 2030 Sustainable Development agenda includes 17 goals and 169 targets, including zero hunger, sustainable agriculture and climate action [United Nations 2015].

This section focuses on intra – and inter-linkages of SDG 2 and SDG 13 based on the official SDG indicators [Figure 5.16], showing the current conditions [Roy et al. [2018] and Chapter 7 for further discussion]. The second goal [Zero Hunger – SDG 2] aims to end hunger and all forms of malnutrition by 2030 and commits to universal access to safe, nutritious and sufficient food at all times of the year. SDG 13 [Climate Action] calls for urgent action to combat climate change and its impacts. Integrating the SDGs into the global food system can provide opportunities for mitigation and adaptation and enhancement of food security.

Ensuring food security [SDG 2] shows positive relations [synergies] with most goals, according to Pradhan et al. [2017] and the International Council for Science [ICSU] [2017], but has trade-offs with SDG 12 [Responsible Consumption and Production] and SDG 15 [Life on Land] under current development paradigms [Pradhan et al. 2017]. Sustainable transformation of traditional consumption and production approaches can overcome these trade-offs based on several innovative methods [Shove et al. 2012]. For example, sustainable intensification and reduction of food waste can minimise the observed negative relations between SDG 2 and other goals [Obersteiner et al. 2016] [Cross-Chapter Box 6 in Chapter 5 and Section 5.5.2]. Achieving target 12.3 of SDG 12 ‘by 2030, to halve per capita global food waste at the retail and consumer levels and reduce food losses along production and supply chains, including post-harvest losses’ will contribute to climate change mitigation.

Doubling productivity of smallholder farmers and halving food loss and waste by 2030 are targets of SDG 2 and SDG 12, respectively [United Nations Statistics Division 2016]. Agroforestry that promotes biodiversity and sustainable land management also contributes to food security [Montagnini and Metzel 2017]. Land restoration and protection [SDG 15] can increase crop productivity [SDG 2] [Wolff et al. 2018]. Similarly, efficient irrigation practices can reduce water demand for agriculture that could improve the health of the freshwater ecosystem [SDG 6 and SDG 15] without reducing food production [Jägermeyr et al. 2017].

Climate action [SDG 13] shows negative relations [trade-offs] with most goals and is antagonistic to the 2030 development agenda under the current development paradigm [Figure 5.16] [Lusseau and Mancini 2019 and Pradhan 2019]. The targets for SDG 13 have a strong focus on climate change adaptation, and the data for the SDG 13 indicators are limited. SDG 13 shares two indicators with SDG 1 and SDG 11 [United Nations 2017] and therefore, has mainly positive linkages with these two goals. Trade-offs were observed between SDG 2 and SDG 13 for around 50% of the linkages analysed [Pradhan et al. 2017].

Transformation from current development paradigms and the breaking of these lock-in effects can protect climate and achieve food security in future. Sustainable agriculture practices can provide climate change adaptation and mitigation synergies, linking SDG 2 and SDG 13 more positively, according to the International Council for Science [ICSU] [2017]. IPCC found that most of the current observed trade-offs between SDG 13 and other SDGs can be converted into synergies based on various mitigation options that can be deployed to limit the global warming well below 1.5°C [IPCC 2018b].

In summary, there are fundamental synergies that can facilitate the joint implementation of strategies to achieve SDGs and climate action, with particular reference to those climate response strategies related to both supply side [production and supply chains] and demand side [consumption and dietary choices] described in this chapter [high agreement and medium evidence].

Figure 5.16

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Intra and inter-linkages for SDG 2 [Zero Hunger] and SDG 13 [Climate Action] at the global level using the official indicators of Sustainable Development Goals that consist of data for 122 indicators for a total of 227 countries between the years 1983 and 2016 [United Nations Statistics Division 2016]. Synergies and trade-offs defined as significant […]

Intra and inter-linkages for SDG 2 [Zero Hunger] and SDG 13 [Climate Action] at the global level using the official indicators of Sustainable Development Goals that consist of data for 122 indicators for a total of 227 countries between the years 1983 and 2016 [United Nations Statistics Division 2016]. Synergies and trade-offs defined as significant positive [ρ > 0.6, red bar] and negative [ρ < –0.6, green bar] Spearman’s correlation between SDG indicators, respectively; ρ between 0.6 and –0.6 is considered as nonclassifieds [yellow bar] [Pradhan et al. 2017]. Grey bars show insufficient data for analysis; white box shows number of data pairs used in analysis. The correlation between unique pairs of indicator time-series is carried based on country data. For example, between ‘prevalence of undernourishment’ [an indicator for SDG 2.1] and ‘maternal mortality ratio’ [an indicator for SDG 3.1]. The data pairs can belong to the same goal or to two distinct goals. At the global level, intra-linkages of SDGs are quantified by the percentage of synergies, trade-offs, and nonclassifieds of indicator pairs belonging to the same SDG for all the countries. Similarly, SDG interlinkages are estimated by the percentage of synergies, trade-offs, and nonclassifieds between indicator pairs that fall into two distinct goals for all the countries.

5.7.1

Enabling policy environments

The scope for responses to make sustainable land use inclusive of climate change mitigation and adaptation, and the policies to implement them, are covered in detail in Chapters 6 and 7. Here we highlight some of the major policy areas that have shaped the food system, and might be able to shape responses in future. Although two families of policy – agriculture and trade – have been instrumental in shaping the food system in the past [and potentially have led to conditions that increase climate vulnerability] [Benton and Bailey 2019], a much wider family of policy instruments can be deployed to reconfigure the food system to deliver healthy diets in a sustainable way.

5.7.1.1

Agriculture and trade policy

Agriculture. The thrust of agricultural policies over the last 50 years has been to increase productivity, even if at the expense of environmental sustainability [Benton and Bailey 2019]. For example, in 2007–2009, 46% of OECD support for agriculture was based on measures of output [price support or payments based on yields], 37% of support was based on the current or historical area planted, herd size [or correlated measures of the notional costs of farming], and 13% was payments linked to input prices. In a similar vein, non-OECD countries have promoted productivity growth for their agricultural sectors.

Trade. Along with agricultural policy to grow productivity, the development of frameworks to liberalise trade [such as the General Agreement on Tariffs and Trade – GATT – Uruguay Round, now incorporated into the World Trade Organization] have been essential in stimulating the growth of a globalised food system. Almost every country has a reliance on trade to fulfil some or all of its local food needs, and trade networks have grown to be highly complex [Puma et al. 2015; MacDonald et al. 2015; Fader et al. 2013 and Ercsey-Ravasz et al. 2012]. This is because many countries lack the capacity to produce sufficient food due to climatic conditions, soil quality, water constraints, and availability of farmland [FAO 2015b]. In a world of liberalised trade, using comparative advantage to maximise production in high-yielding commodities, exporting excess production, and importing supplies of other goods supports economic growth.

City states as well as many small island states, do not have adequate farmland to feed their populations, while Sub-Saharan African countries are projected to experience high population growth as well as to be negatively impacted by climate change, and thus will likely find it difficult to produce all of their own food supplies [Agarwal et al. 2002]. One study estimates that some 66 countries are currently incapable of being self-sufficient in food [Pradhan et al. 2014]. Estimates of the proportion of people relying on trade for basic food security vary from about 16% to about 22% [Fader et al. 2013; Pradhan et al. 2014], with this figure rising to between 1.5 and 6 billion people by 2050, depending on dietary shifts, agricultural gains, and climate impacts [Pradhan et al. 2014].

Global trade is therefore essential for achieving food and nutrition security under climate change because it provides a mechanism for enhancing the efficiency of supply chains, reducing the vulnerability of food availability to changes in local weather, and moving production from areas of surplus to areas of deficit [FAO 2018d]. However, the benefits of trade will only be realised if trade is managed in ways that maximise broadened access to new markets while minimising the risks of increased exposure to international competition and market volatility [Challinor et al. 2018; Brown et al. 2017b].

As described in Section 5.8.1, trade acts to buffer exposure to climate risks when the market works well. Under certain conditions – such as shocks, or the perception of a shock, coupled with a lack of food stocks or lack of transparency about stocks [Challinor et al. 2018; Marchand et al. 2016] – the market can fail and trade can expose countries to food price shocks.

Furthermore, Clapp [2016] showed that trade, often supported by high levels of subsidy support to agriculture in some countries, can depress world prices and reduce incomes for other agricultural exporters. Lower food prices that result from subsidy support may benefit urban consumers in importing countries, but at the same time they may hurt farmers’ incomes in those same countries. The outmigration of smallholder farmers from the agriculture sector across the Global South is significantly attributed to these trade patterns of cheap food imports [Wittman 2011; McMichael 2014; Akram-Lodhi et al. 2013]. Food production and trade cartels, as well as financial speculation on food futures markets, affect low-income market-dependent populations.

Food sovereignty is a framing developed to conceptualise these issues [Reuter 2015]. They directly relate to the ability of local communities and nations to build their food systems, based, among other aspects, on diversified crops and ILK. If a country enters international markets by growing more commodity crops and reducing local crop varieties, it may get economic benefits, but may also expose itself to climate risks and food insecurity by increasing reliance on trade, which may be increasingly disrupted by climate risks. These include a local lack of resilience from reduced diversity of products, but also exposure to food price spikes, which can become amplified by market mechanisms such as speculation.

In summary, countries must determine the balance between locally produced versus imported food [and feed] such that it both minimises climate risks and ensures sustainable food security. There is medium evidence that trade has positive benefits but also creates exposure to risks [Section 5.3].

5.7.1.2

Scope for expanded policies

There are a range of ways that policy can intervene to stimulate change in the food system – through agriculture, research and development, food standards, manufacture and storage, changing the food environment and access to food, changing practices to encourage or discourage trade [Table 5.6]. Novel incentives can stimulate the market, for example, through reduction in waste or changes in diets to gain benefits from a health or sustainability direction. Different contexts with different needs will require different set of policies at local, regional and national levels. See Supplementary Material Section SM5.7 for further discussion on expanded policies.

In summary, although agriculture is often thought to be shaped predominantly by agriculture and trade policies, there are over twenty families of policy areas that can shape agricultural production directly or indirectly [through environmental regulations or through markets, including by shaping consumer behaviour]. Thus, delivering outcomes promoting climate change adaptation and mitigation can arise from policies across many departments, if suitably designed and aligned.

Table 5.6

Potential policy ‘families’ for food-related adaptation and mitigation of climate change. The column ‘scale’ refers to scale of implementation: International [I], national [N], sub-national-regional [R], and local [L].

5.7.1.3

Health-related policies and cost savings

The co-benefits arising from mitigating climate change through changing dietary patterns, and thus demand, have potentially important economic impacts [high confidence]. The gross value added from agriculture to the global economy [GVA] was 1.9 trillion USD2013 [FAO 2015c], from a global agriculture economy [GDP] of 2.7 trillion USD2016. In 2013, the FAO estimated an annual cost of 3.5 trillion USD for malnutrition [FAO 2013a].

However, this is likely to be an underestimate of the economic health costs of current food systems for several reasons: [i] lack of data – for example there is little robust data in the UK on the prevalence of malnutrition in the general population [beyond estimates of obesity and surveys of malnourishment of patients in hospital and care homes, from which estimates over 3 million people in the UK are undernourished [BAPEN 2012]; [ii] lack of robust methodology to determine, for example, the exact relationship between over-consumption of poor diets, obesity and non-communicable diseases like diabetes, cardiovascular disease, a range of cancers or Alzheimer’s disease [Pedditizi et al. 2016], and [iii] unequal healthcare spending around the world.

In the USA, the economic cost of diabetes, a disease strongly associated with obesity and affecting about 23 million Americans, is estimated at 327 billion USD2017 [American Diabetes Association 2018], with direct healthcare costs of 9600 USD per person. By 2025, it is estimated that, globally, there will be over 700 million people with diabetes [NCD-RisC 2016b], over 30 times the number in the USA. Even if a global average cost of diabetes per capita were a quarter of that in the USA, the total economic cost of diabetes would be approximately the same as global agricultural GDP. Finally, [iv] the role of agriculture in causing ill-health beyond dietary health, such as through degrading air quality [e.g., Paulot and Jacob 2014].

Whilst data of the healthcare costs associated with the food system and diets are scattered and the proportion of costs directly attributable to diets and food consumption is uncertain, there is potential for more preventative healthcare systems to save significant costs that could incentivise agricultural business models to change what is grown, and how. The potential of moving towards more preventative healthcare is widely discussed in health economics literature, particularly in order to reduce the life-style-related [including dietary-related] disease component in aging populations [e.g., Bloom et al. 2015].

5.7.1.4

Multiple policy pathways

As discussed in more detail in Chapters 6 and 7, there is a wide potential suite of interventions and policies that can potentially enhance the adaptation of food systems to climate change, as well as enhance the mitigation potential of food systems on climate change. There is an increasing number of studies that argue that the key to sustainable land management is not in land management practices but in the factors that determine the demand for products from land [such as food]. Public health policy, therefore, has the potential to affect dietary choice and thus the demand for different amounts of, and types of, food.

Obersteiner et al. [2016] show that increasing the average price of food is an important policy lever that, by reducing demand, reduces food waste, pressure on land and water, impacts on biodiversity and through reducing emissions, mitigates climate change and potentially helps to achieve multiple SDGs. Whilst such policy responses – such as a carbon tax applied to goods including food – has the potential to be regressive, affecting the poor differentially [Frank et al. 2017; Hasegawa et al. 2018 and Kehlbacher et al. 2016], and increasing food insecurity – further development of social safety nets can help to avoid the regressive nature [Hasegawa et al. 2018]. Hasegawa et al. [2018] point out that such safety nets for vulnerable populations could be funded from the revenues arising from a carbon tax.

The evidence suggests, as with SR15 [IPCC 2018a] and its multiple pathways to climate change solutions, that there is no single solution that will address the problems of food and climate change, but instead there is a need to deploy many solutions, simultaneously adapted to the needs and options available in a given context. For example, Springmann et al. [2018a] indicate that maintaining the food system within planetary boundaries at mid-century, including equitable climate, requires increasing the production [and resilience] of agricultural outputs [i.e., closing yield gaps], reducing waste, and changes in diets towards ones often described as flexitarian [low-meat dietary patterns that are in line with available evidence on healthy eating]. Such changes can have significant co-benefits for public health, as well as facing significant challenges to ensure equity [in terms of affordability for those in poverty].

Significant changes in the food system require them to be acceptable to the public [‘public license’], or they will be rejected. Focus groups with members of the public around the world, on the issue of changing diets, have shown that there is a general belief that the government plays a key role in leading efforts for change in consumption patterns [Wellesley et al. 2015]. If governments are not leading on an issue, or indicating the need for it through leading public dialogue, it signals to their citizens that the issue is unimportant or undeserving of concern.

In summary, there is significant potential [high confidence] that, through aligning multiple policy goals, multiple benefits can be realised that positively impact public health, mitigation and adaptation [e.g., adoption of healthier diets, reduction in waste, reduction in environmental impact]. These benefits may not occur without the alignment across multiple policy areas [high confidence].

5.7.2

Enablers for changing markets and trade

‘Demand’ for food is not an exogenous variable to the food system but is shaped crucially by its ability to produce, market, and supply food of different types and prices. These market dynamics can be influenced by a variety of factors beyond consumer preferences [e.g., corporate power and marketing, transparency, the food environment more generally], and the ability to reshape the market can also depend on its internal resilience and/or external shocks [Challinor et al. 2018; Oliver et al. 2018].

5.7.2.1

Capital markets

Two areas are often discussed regarding the role of capital markets in shaping the food system. First, investment in disruptive technologies might stimulate climate-smart food systems [WEF/ McKinsey & Company 2018 and Bailey and Wellesley 2017], including alternative proteins, such as laboratory or ‘clean meat’ [which has significant ability to impact on land-use requirements] [Alexander et al. 2017] [Section 5.5.1.6]. An innovation environment through which disruptive technology can emerge typically requires the support of public policy, whether in directly financing small and emerging enterprises, or funding research and development via reducing tax burdens.

Second, widespread adoption of [and perhaps underpinned by regulation for] natural capital accounting as well as financial accounting are needed. Investors can then be aware of the risk exposure of institutions, which can undermine sustainability through externalising costs onto the environment. The prime example of this in the realm of climate change is the Carbon Disclosure Project, with around 2500 companies voluntarily disclosing their carbon footprint, representing nearly 60% of the world’s market capital [CDP 2018].

5.7.2.2

Insurance and re-insurance

The insurance industry can incentivise actors’ behaviour towards greater climate mitigation or adaptation, including building resilience. For example, Lloyd’s of London analysed the implications of extreme weather for the insurance market, and conclude that the insurance industry needs to examine their exposure to risks through the food supply chain and develop innovative risk-sharing products that can make an important contribution to resilience of the global food system [Lloyd’s 2015].

Many of these potential areas for enabling healthy and sustainable food systems are also knowledge gaps, in that, whilst the levers are widely known, their efficacy and the ability to scale-up, in any given context, are poorly understood.

5.7.3

Just Transitions to sustainability

Research is limited on how land-use transitions would proceed from ruminant production to other socio-ecological farming systems. Ruminants have been associated with humans since the early development of agriculture, and the role of ruminants in many agricultural systems and smallholder communities is substantial. Ruminant production systems have been adapted to a wide range of socioeconomic and environmental conditions in crop, forestry, and food processing settings [Čolović et al. 2019], bioenergy production [de Souza et al. 2019], and food waste recycling [Westendorf 2000]. Pasture cultivation in succession to crops is recognised as important to management of pest and diseases cycles and to improve soil carbon stocks and soil quality [Carvalho and Dedieu 2014]. Grazing livestock is important as a reserve of food and economic stocks for some smallholders [Ouma et al. 2003].

Possible land-use options for transitions away from livestock production in a range of systems include [a] retain land but reduce investments to run a more extensive production system; [b] change land use by adopting a different production activity; [c] abandon land [or part of the farm] to allow secondary vegetation regrowth [Carvalho et al. 2019 and Laue and Arima 2016]; and [d] invest in afforestation or reforestation [Baynes et al. 2017]. The extensification option could lead to increases rather than decreases in GHG emissions related to reduction in beef consumption. Large-scale abandonment, afforestation, or reforestation would probably have more positive environmental outcomes, but could result in economic and social issues that would require governmental subsidies to avoid decline and migration in some regions [Henderson et al. 2018].

Alternative economic use of land, such as bioenergy production, could balance the negative socioeconomic impact of reducing beef output, reduce the tax values needed to reduce consumption, and avoid extensification of ruminant production systems [Wirsenius et al. 2011]. However, the analysis of the transition of land use for ruminants to other agricultural production systems is still a literature gap [Cross-Chapter Box 7 in Chapter 6].

Finally, it is important to recognise that, while energy alternatives produce the same function for the consumer, it is questionable that providing the same nutritional value through an optimised mix of dietary ingredients provides the same utility for humans. Food has a central role in human pleasure, socialisation, cultural identity, and health [Röös et al. 2017], including some of the most vulnerable groups, so Just Transitions and their costs need to be taken into account. Pilot projects are important to provide greater insights for large-scale policy design, implementation, and enforcement.

In summary, more research is needed on how land-use transitions would proceed from ruminant production to other farming systems and affect the farmers and other food system actors involved. There is limited evidence on what the decisions of farmers under lower beef demand would be.

5.7.4

Mobilising knowledge

Addressing climate change-related challenges and ensuring food security requires all types of knowledge [formal/non-formal, scientific/ indigenous, women, youth, technological]. Miles et al. [2017] stated that a research and policy feedback that allows transitions to sustainable food systems must take a whole system approach. Currently, in transmitting knowledge for food security and land sustainability under climate change there are three major approaches: [i] public technology transfer with demonstration [extension agents]; [ii] public and private advisory services [for intensification techniques] and; [iii] non-formal education with many different variants such as farmer field schools, rural resource centres; facilitation extension where front-line agents primarily work as ‘knowledge brokers’ in facilitating the teaching-learning process among all types of farmers [including women and rural young people], or farmer-to-farmer, where farmers act themselves as knowledge transfer and sharing actors through peer processes.

5.7.4.1

Indigenous and local knowledge

Recent discourse has a strong orientation towards scaling-up innovation and adoption by local farmers. However, autonomous adaptation, indigenous knowledge and local knowledge are both important for agricultural adaptation [Biggs et al.2013][Section5.3].These involve the promotion of farmer participation in governance structures, research, and the design of systems for the generation and dissemination of knowledge and technology, so that farmers’ needs and knowledge can be taken into consideration. Klenk et al. [2017] found that mobilisation of local knowledge can inform adaptation decision-making and may facilitate greater flexibility in government-funded research. As an example, rural innovation in terrace agriculture developed on the basis of a local coping mechanism and adopted by peasant farmers in Latin America may serve as an adaptation option or starting place for learning about climate change responses [Bocco and Napoletano 2017]. Clemens et al. [2015] found that an open dialogue platform enabled horizontal exchange of ideas and alliances for social learning and knowledge-sharing in Vietnam. Improving local technologies in a participatory manner, through on-farm experimentation, farmer-to- farmer exchange, consideration of women and youths, is also relevant in mobilising knowledge and technologies.

Citizen science has been tested as a useful tool with potential for biodiversity conservation [Schmitz et al. 2015] and mobilising knowledge from society. In food systems, knowledge-holders [e.g., farmers and pastoralists] are trained to gather scientific data in order to promote conservation and resource management [Fulton et al. 2019] or to conserve and use traditional knowledge in developed countries relevant to climate change adaptation and mitigation through the use of ICT [Calvet-Mir et al. 2018].

5.7.4.3

Capacity building and education

Mobilising knowledge may also require significant efforts on capacity building and education to scale up food system responses to climate change. This may involve increasing the capacity of farmers to manage current climate risks and to mitigate and adapt in their local contexts, and of citizens and consumers to understand the links between food demand and climate change emissions and impacts, as well as policy makers to take a systemic view of the issues. Capacity building may also require institutional change. For example, alignment of policies towards sustainable and healthy food systems may require building institutional capacity across policy silos.

As a tool for societal transformation, education is a powerful strategy to accelerate changes in the way we produce and consume food. Education refers to early learning and lifelong acquisition of skills for higher awareness and actions for solving food system challenges [FAO 2005]. Education also entails vocational training, research and institutional strengthening [Hollinger 2015]. Educational focus changes according to the supply side [e.g., crop selection, input resource management, yield improvement, and diversification] and the demand since [nutrition and dietary health implications]. Education on food loss and waste spans both the supply and demand sides.

In developing countries, extension learning such as farmer field schools – also known asrural resources centers – are established to promote experiential learning on improved production and food transformation [FAO 2016c]. In developed countries, education campaigns are being undertaken to reduce food waste, improve diets and redefine acceptable food [e.g., “less than perfect” fruits and vegetables], and ultimately can contribute to changes in the structure of food industries [Heller 2019; UNCCD 2017].

The design of new education modules from primary to secondary to tertiary education could help create new jobs in the realm of sustainability [e.g., certification programmes]. For example, one area could be educating managers of recycling programmes for food-efficient cities where food and organic waste are recycled to become fertilisers [Jara-Samaniego et al. 2017]. Research and education need to be coordinated so that knowledge gaps can be filled and greater trust established in shifting behaviour of individuals to be more sustainable. Education campaigns can also influence policy and legislation, and help to advance successful outcomes for climate change mitigation and adaptation regarding supply-side innovations, technologies, trade, and investment, and demand-side evolution of food choices for health and sustainability, and greater gender equality throughout the entire food system [Heller 2019].

5.7.5

Knowledge gaps and key research areas

Knowledge gaps around options and solutions and their [co-]benefits and trade-offs are increasingly important now that implementation of mitigation and adaptation measures is scaling up.

Research is needed on how a changing climate and interventions to respond to it will affect all aspects of food security, including access, utilisation and stability, not just availability. Knowledge gaps across all the food security pillars are one of the barriers hindering mitigation and adaptation to climate change in the food system and its capacity to deliver food security. The key areas for climate change, food systems, and food security research are enlisted below.

5.7.5.1

Impacts and adaptation

Climate Services [food availability]. Agriculture and food security is a priority area for the Global Framework for Climate Services [GFCS] a programme of the World Meteorological Organization [WMO]. The GFCS enables vulnerable sectors and populations to better manage climate variability and adapt to climate change [Hansen et al. 2018]. Global precipitation datasets and remote sensing technologies can be used to detect local to regional anomalies in precipitation as a tool for devising early-warning systems for drought-related impacts, such as famine [Huntington et al. 2017].

Crop and livestock genetics [food availability, utilisation]. Advances in plant breeding are crucial for enhancing food security under changing climate for a wide variety of crops including fruits and vegetables as well as staples. Genetics improvement is needed in order to breed crops and livestock that can both reduce GHG emissions, increase drought and heat tolerance [e.g., rice], and enhance nutrition and food security [Nankishore and Farrell 2016; Kole et al. 2015]. Many of these characteristics already exist in traditional varieties, including orphan crops and indigenous and local breeds, so research is needed to recuperate such varieties and evaluate their potential for adaptation and mitigation.

Phenomics-assisted breeding appears to be a promising tool for deciphering the stress responsiveness of crop and animal species [Papageorgiou 2017; Kole et al. 2015; Lopes et al. 2015; Boettcher et al. 2015]. Initially discovered in bacteria and archaea, CRISPR–Cas9 is an adaptive immune system found in prokaryotes and since 2013 has been used as a genome editing tool in plants. The main use of CRISPR systems is to achieve improved yield performance, biofortification, biotic and abiotic stress tolerance, with rice [Oryza sativa] being the most studied crop [Gao 2018 and Ricroch et al. 2017].

Climate impact models [food availability]. Understanding the full range of climate impacts on staple crops [especially those important in developing countries, such as fruits and vegetables] is missing in the current climate impact models. Further, the CO2 effects on nutrition quality of different crops are just beginning to be parameterised in the models [Müller et al. 2014]. Bridging these gaps is essential for projecting future dietary diversity, healthy diets, and food security [Bisbis et al. 2018]. Crop model improvements are needed for simulation of evapotranspiration to guide crop water management in future climate conditions [Cammarano et al. 2016]. Similarly, mores studies are needed to understand the impacts of climate change on global rangelands, livestock and aquaculture, which have received comparatively less attention than the impacts on crop production.

Resilience to extreme events [food availability, access, utilisation, and stability]. On the adaptation side, knowledge gaps include impacts of climate shocks [Rodríguez Osuna et al. 2014] as opposed to impacts of slow-onset climate change, how climate-related harvest failures in one continent may influence food security outcomes in others, impacts of climate change on fruits and vegetables and their nutrient contents.

5.7.5.2

Emissions and mitigation

GHG emissions inventory techniques [food utilisation]. Knowledge gaps include food consumption-based emissions at national scales, embedded emissions [overseas footprints] of food systems, comparison of GHG emissions per type of food systems [e.g., smallholder and large-scale commercial food systems], and GHG emissions from land-based aquaculture. An additional knowledge gap is the need for more socio-economic assessments of the potential of various integrated practices to deliver the mitigation potential estimated from a biophysical perspective. This needs to be effectively monitored, verified, and implemented, once barriers and incentives to adoption of the techniques, practices, and technologies are considered. Thus, future research needs fill the gaps on evaluation of climate actions in the food system.

Food supply chains [food availability]. The expansion of the cold chain into developing economies means increased energy consumption and GHG emissions at the consumer stages of the food system, but its net impact on GHG emissions for food systems as a whole, is complex and uncertain [Heard and Miller 2016]. Further understanding of negative side effects in intensive food processing systems is still needed.

Blockchains, as a distributed digital ledger technology which ensures transparency, traceability, and security, is showing promise for easing some global food supply chain management challenges, including the need for documentation of sustainability and the circular economy for stakeholders including governments, communities, and consumers to meet sustainability goals. Blockchain-led transformation of food supply chains is still in its early stages; research is needed on overcoming barriers to adoption [Tripoli and Schmidhuber 2018; Casado-Vara et al. 2018; Mao et al. 2018; Saberi et al. 2019].

5.7.5.3

Synergies and trade-offs

Supply-side and demand-side mitigation and adaptation [food availability, utilisation]. Knowledge gaps exist in characterising the potential and risks associated with novel mitigation technologies on the supply side [e.g., inhibitors, targeted breeding, cellular agriculture, etc.]. Additionally, most integrated assessment models [IAMs] currently have limited regional data on BECCS projects because of little BECCS implementation [Lenzi et al. 2018]. Hence, several BECCS scenarios rely on assumptions regarding regional climate, soils and infrastructure suitability [Köberle et al. 2019] as well as international trade [Lamers et al. 2011].

Areas for study include how to incentivise, regulate, and raise awareness of the co-benefits of healthy consumption patterns and climate change mitigation and adaptation; to improve access to healthy diets for vulnerable groups through food assistance programmes; and to implement policies and campaigns to reduce food loss and food waste. Knowledge gaps also exist on the role of different policies, and underlying uncertainties, to promote changes in food habits towards climate resilience and healthy diets.

Food systems, land-use change, and telecoupling [food availability, access, utilisation]. The analytical framework of telecoupling has recently been proposed to address this complexity, particularly the connections, flows, and feedbacks characterising food systems [Friis et al. 2016; Easter et al. 2018]. For example, how will climate-induced shifts in livestock and crop diseases affect food production and consumption in the future. Investigating the social and ecological consequences of these changes will contribute to decision-making under uncertainty in the future. Research areas include food systems and their boundaries, hierarchies, and scales through metabolism studies, political ecology and cultural anthropology.

Food-Energy-Water Nexus [food availability, utilisation, stability]. Emerging interdisciplinary science efforts are providing new understanding of the interdependence of food, energy, and water systems. These interdependencies are beginning to take into account climate change, food security, and AFOLU assessments [Scanlon et al. 2017; Liu et al. 2017]. These science advances, in turn, provide critical information for coordinated management to improve the affordability, reliability, and environmental sustainability of food, energy, and water systems. Despite significant advances within the past decade, there are still many challenges for the scientific community. These include the need for interdisciplinary science related to the food-energy-water nexus; ground-based monitoring and modelling at local-to-regional scales [Van Gaelen et al. 2017]; incorporating human and institutional behaviour in models; partnerships among universities, industry, and government to develop policy-relevant data; and systems modelling to evaluate trade-offs associated with food-energy-water decisions [Scanlon et al. 2017].

However, the nexus approach, as a conceptual framework, requires the recognition that, although land and the goods and services it provides is finite, potential demand for the goods and services may be greater than the ability to supply them sustainably [Benton et al. 2018]. By addressing demand-side issues, as well as supply-side efficiencies, it provides a potential route for minimising trade-offs for different goods and services [Benton et al. 2018] [Section 5.6].

5.8.1

Food price spikes

Under average conditions, global food system markets may function well, and equilibrium approaches can estimate demand and supply with some confidence; however, if there is a significant shock, the market can fail to smoothly link demand and supply through price, and a range of factors can act to amplify the effects of the shock, and transmit it across the world [Box 5.5]. Given the potential for shocks driven by changing patterns of extreme weather to increase with climate change, there is the potential for market volatility to disrupt food supply through creating food price spikes. This potential is exacerbated by the interconnectedness of the food system [Puma et al. 2015] with other sectors [i.e., the food system depends on water, energy, and transport] [Homer-Dixon et al. 2015], so the impact of shocks can propagate across sectors and geographies [Homer-Dixon et al. 2015]. There is also less spare land globally than there has been in the past, such that if prices spike, there are fewer options to bring new production on stream [Marianela et al. 2016].

Increasing extreme weather events can disrupt production and transport logistics. For example, in 2012 the USA Corn Belt suffered a widespread drought; USA corn yield declined 16% compared to 2011 and 25% compared to 2009. In 2016, a record yield loss in France that is attributed to a conjunction of abnormal warmness in late autumn and abnormal wet in the following spring [Ben-Ari et al. 2018] is another well-documented example. To the extent that such supply shocks are associated with climate change, they may become more frequent and contribute to greater instability in agricultural markets in the future.

Furthermore, analogue conditions of past extremes might create significantly greater impacts in a warmer world. A study simulating analogous conditions to the Dust Bowl drought in today’s agriculture suggests that Dust Bowl-type droughts today would have unprecedented consequences, with yield losses about 50% larger than the severe drought of 2012 [Glotter and Elliott 2016]. Damages at these extremes are highly sensitive to temperature, worsening by about 25% with each degree centigrade of warming. By mid-century, over 80% of summers are projected to have average temperatures that are likely to exceed the hottest summer in the Dust Bowl years [1936] [Glotter and Elliott 2016].

Figure 5.17

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Underlying processes that affect the development of a food price spike in agricultural commodity markets [Challinor et al. 2018].

Underlying processes that affect the development of a food price spike in agricultural commodity markets [Challinor et al. 2018].

How a shortfall in production – or an interruption in trade due to an event affecting a logistics choke-point [Wellesley et al. 2017] – of any given magnitude may create impacts depends on many interacting factors [Homer-Dixon et al. 2015; Tadasse et al. 2016; Challinor et al. 2018]. The principal route is by affecting agricultural commodity markets, which respond to a perturbation through multiple routes as in Figure 5.17. This includes pressures from other sectors [such as, if biofuels policy is incentivising crops for the production of ethanol, as happened in 2007–2008]. The market response can be amplified by poor policies, setting up trade and non-trade barriers to exports, from countries seeking to ensure their local food security [Bailey et al. 2015]. Furthermore, the perception of problems can fuel panic buying on the markets that in turn drives up prices.

Thus, the impact of an extreme weather event on markets has both a trigger component [the event] and a risk perception component [Challinor et al. 2016, 2018]. Through commodity markets, prices change across the world because almost every country depends, to a greater or lesser extent, on trade to fulfil local needs. Commodity prices can also affect local market prices by altering input prices, changing the cost of food aid, and through spill-over effects. For example, in 2007– 2008 the grain affected by extreme weather was wheat, but there was a significant price spike in rice markets [Dawe 2010].

As discussed by Bailey et al. [2015], there are a range of adaptation measures that can be put in place to reduce the impact of climate-related production shortfalls. These include [i] ensuring transparency of public and private stocks, as well as improved seasonal forecasting to signal forthcoming yield shortfalls [FAO 2016a; Ceglar et al. 2018; Iizumi et al. 2018], [ii] building real or virtual stockholdings, [iii] increasing local productivity and diversity [as a hedge against a reliance on trade] and [iv] ensuring smoother market responses, through, for example, avoiding the imposition of export bans.

In summary, given the likelihood that extreme weather will increase, in both frequency and magnitude [Hansen et al. 2012; Coumou et al. 2014; Mann et al. 2017; Bailey et al. 2015], and the current state of global and cross-sectoral interconnectedness, the food system is at increasing risk of disruption [medium evidence, medium agreement], with large uncertainty about how this could manifest. There is, therefore, a need to build resilience into international trade as well as local supplies.

Box 5.5

Market drivers and the consequences of extreme weather in 2010–2011

The 2010–2011 food price spike was initially triggered by the exceptional heat in summer 2010, with an extent from Europe to the Ukraine and Western Russia [Barriopedro et al. 2011; Watanabe et al. 2013; Hoag 2014]. The heatwave in Russia was extreme in both temperature [over 40°C] and duration [from July to mid-August in 2010]. This reduced wheat yields by approximately one third [Wegren 2011; Marchand et al. 2016]. Simultaneously, in the Indus Valley in Pakistan, unprecedented rainfall led to flooding, affecting the lives and livelihoods of 20 million people. There is evidence that these effects were both linked and made more likely through climate change [Mann et al. 2017].

In response to its shortfall in yields, Russia imposed an export ban in order to maintain local food supplies. Other countries responded in a largely uncoordinated ways, each of them driven by internal politics as well as national self-interests [Jones and Hiller 2017]. Overall, these measures led to rapid price rises on the global markets [Welton 2011], partly through panic buying, but also through financial speculation [Spratt 2013].

Analysis of responses to higher food prices in the developing world showed that lower-income groups responded by taking on more employment, reducing food intake, limiting expenditures, spending savings [if available], and participating in demonstrations. People often identified their problems as stemming from collusion between powerful incumbent interests [e.g., of politicians and big business] and disregard for the poor [Hossain and Green 2011]. This politicised social response helped spark food-related civil protest, including riots, across a range of countries in 2010–2011 [Natalini et al. 2017]. In Pakistan, food price rises were exacerbated by the economic impacts of the floods, which further contributed to food-related riots in 2010.

Price spikes also impact on food security in the developed world. In the UK, global commodity price inflation influenced local food prices, increasing food-price inflation by about five times at the end of 2010. Comparing household purchases over the five-year period from 2007 to 2011 showed that the amount of food bought declined, on average, by 4.2%, whilst paying 12% more for it. The lowest income decile spent 17% more by 2011 than they did in 2007 [Holding et al. 2013; Tadasse et al. 2016]. Consumers also saved money by trading down for cheaper alternatives. For the poorest, in the extreme situation, food became unaffordable: the Trussell Trust, a charity supplying emergency food handouts for people in crisis, noted a 50% increase in handouts in 2010.

5.8.2

Migration and conflict

Since the IPCC AR5 [Porter et al. 2014; Cramer et al. 2014], new work has advanced multi-factor methodological issues related to migration and conflict [e.g., Kelley et al. 2015, 2017; Werrell et al. 2015; Challinor et al. 2018; Pasini et al. 2018]. These in particular have addressed systemic risks to food security that result from cascading impacts triggered by droughts and floods and how these are related to a broad range of societal influences.

Climate variability and extremes have short-, medium – and long-term impacts on livelihoods and livelihood assets – especially of the poor – contributing to greater risk of food insecurity and malnutrition [FAO et al. 2018]. Drought threatens local food security and nutrition and aggravates humanitarian conditions, which can trigger large-scale human displacement and create a breeding ground for conflict [Maystadt and Ecker 2014]. There is medium agreement that existing patterns of conflict could be reinforced under climate change, affecting food security and livelihood opportunities, for example, in already fragile regions with ethnic divides such as North and Central Africa as well as Central Asia [Buhaug 2016; Schleussner et al. 2016] [Box 5.6].

Challinor et al. [2018] have developed a typology for transboundary and transboundary risk transmission that distinguishes the roles of climate and social and economic systems. To understand these complex interactions, they recommend a combination of methods that include expert judgement; interactive scenario building; global systems science and big data; and innovative use of climate and integrated assessment models; and social science techniques [e.g., surveys, interviews, and focus groups].

5.8.2.1

Migration

There has been a surge in international migration in recent years, with around five million people migrating permanently in 2016 [OECD 2017]. Though the initial driver of migration may differ across populations, countries and contexts, migrants tend to seek the same fundamental objective: to provide security and adequate living conditions for their families and themselves. Food insecurity is a critical ‘push’ factor driving international migration, along with conflict, income inequality, and population growth. The act of migration itself causes food insecurity, given the lack of income opportunities and adverse conditions compounded by conflict situations.

Warner et al. [2012] found the interrelationships between changing rainfall patterns, food and livelihood security in eight countries in Asia, Africa and Latin America. Several studies in Africa have found that persistent droughts and land degradation contributed to both seasonal and permanent migration [Gray 2011; Gray and Mueller 2012; Hummel 2015; Henry et al. 2004; Folami and Folami 2013], worsening the vulnerability of different households [Dasgupta et al. 2014].

Dependency on rainfed agriculture ranges from 13% in Mexico to more than 30% in Guatemala, Honduras, and Nicaragua, suggesting a high degree of sensitivity to climate variability and change, and undermined food security [Warner et al. 2009]. Studies have demonstrated that Mexican migration [Feng et al. 2010; Nawrotzki et al. 2013] and Central American migration [WFP 2017] fluctuate in response to climate variability. The food system is heavily dependent on maize and bean production and long-term climate change and variability significantly affect the productivity of these crops and the livelihoods of smallholder farmers [WFP 2017]. In rural Ecuador, adverse environmental conditions prompt out-migration, although households respond to these challenges in diverse ways resulting in complex migratory responses [Gray and Bilsborrow 2013].

Migration patterns have been linked to heat stress in Pakistan [Mueller et al. 2014] and climate variability in the Sundarbans due to decline in food security [Guha and Roy 2016]. In Bangladesh, the impacts of climate change have been on the rise throughout the last three decades with increasing migration, mostly of men leaving women and children to cope with increasing effects of natural disasters [Rabbani et al. 2015].

Small islands are very sensitive to climate change impacts [high confidence] [Nurse et al. 2014] and impacted by multiple climatic stressors [IPCC 2018a and SROCC]. Food security in the Pacific, especially in Micronesia, has worsened in the past half century and climate change is likely to further hamper local food production, especially in low-lying atolls [Connell 2016]. Migration in small islands [internally and internationally] occurs for multiple reasons and purposes, mostly for better livelihood opportunities [high confidence].

Beyond rising sea levels, the effects of increasing frequency and intensity of extreme events such as severe tropical cyclones are likely to affect human migration in the Pacific [Connell 2015; Krishnapillai and Gavenda 2014; Charan et al. 2017; Krishnapillai 2017]. On Yap Island, extreme weather events are affecting every aspect of atoll communities’ existence, mainly due to the islands’ small size, their low elevation, and extensive coastal areas [Krishnapillai 2018]. Displaced atoll communities on Yap Island grow a variety of nutritious vegetables and use alternative crop production methods such as small-plot intensive farming, raised bed gardening, as part of a community-based adaptation programme [Krishnapillai and Gavenda 2014; Krishnapillai 2018].

Recurrences of natural disasters and crises threaten food security through impacts on traditional agriculture, causing the forced migration and displacement of coastal communities to highlands in search of better living conditions. Although considerable differences occur in the physical manifestations of severe storms, such climate stressors threaten the life-support systems of many atoll communities [Campbell et al. 2014]. The failure of these systems resulting from climate disasters propel vulnerable atoll communities into poverty traps, and low adaptive capacity could eventually force these communities to migrate.

Box 5.6

Migration in the Pacific region: Impacts of climate change on food security

Climate change-induced displacement and migration in the Pacific has received wide attention in the scientific discourse [Fröhlich and Klepp 2019]. The processes of climate change and their effects in the region have serious implications for Pacific Island nations as they influence the environments that are their ‘life-support systems’ [Campbell 2014]. Climate variability poses significant threats to both agricultural production and food security. Rising temperatures and reductions in groundwater availability, as well as increasing frequency and severity of disaster events translate into substantial impacts on food security, causing human displacement, a trend that will be aggravated by future climate impacts [ADB 2017]. Declining soil productivity, groundwater depletion, and non-availability of freshwater threatens agricultural production in many remote atolls.

Many countries in the Pacific devote a large share of available land area to agricultural production. For example, more than 60% of land area is cultivated in the Marshall Islands and Tuvalu and more than 40% in Kiribati and Tonga. With few options to expand agricultural area, the projected impacts of climate change on food production are of particular concern [ADB 2013, 2017]. The degradation of available land area for traditional agriculture, adverse disruptions of agricultural productivity and diminishing livelihood opportunities through climate change impacts leads to increasing poverty and food insecurity, incentivising migration to urban agglomerations [ADB 2017; FAO et al. 2018].

Campbell [2014] describe the trends that lead to migration. First, climate change, including rising sea levels, affects communities’ land security, which is the physical presence on which to live and sustain livelihoods. Second, they impinge on livelihood security [especially food security] of island communities where the productivity of both subsistence and commercial food production systems is reduced. Third, the effects of climate change are especially severe on small-island environments since they result in declining ecological habitat. The effects on island systems are mostly manifested in atolls through erosion and inundation, and on human populations through migration. Population growth and scenarios of climate change are likely to further induce food stress as impacts unfold in the coming decades [Campbell 2015].

While the populations of several islands and island groups in the Pacific [e.g., Tuvalu, Carteret Islands, and Kiribati] have been perceived as the first probable victims of rising seas so that their inhabitants would become, and in some quarters already are seen to be, the first ‘environmental’ or ‘climate change refugees’, migration patterns vary. Especially in small islands, the range and nature of the interactions among economic, social, and/or political drivers are complex. For example, in the Maldives, Stojanov et al. [2017] show that while collective perceptions support climate change impacts as being one of the key factors prompting migration, individual perceptions give more credence to other cultural, religious, economic or social factors.

In the Pacific, Tuvalu has long been a prime candidate to disappear due to rising sea levels, forcing human migration. However, results of a recent study [Kench et al. 2018] challenge perceptions of island loss in Tuvalu, reporting that there is a net increase in land area of 73.5 ha. The findings suggest that islands are dynamic features likely to persist as habitation sites over the next century, presenting opportunities for adaptation that embrace the heterogeneity of island types and processes. Farbotko [2010] and Farbotko and Lazrus [2012] present Tuvalu as a site of ‘wishful sinking’, in the climate change discourse. These authors argue that representations of Tuvalu as a laboratory for global climate change migration are visualisations by non-locals.

In Nanumea [Tuvalu], forced displacements and voluntary migrations are complex decisions made by individuals, families and communities in response to discourses on risk, deteriorating infrastructure and other economic and social pressures [Marino and Lazrus 2015]. In many atoll nations in the Western Pacific, migration has increasingly become a sustainable livelihood strategy, irrespective of climate change [Connell 2015].

In Lamen Bay, Vanuatu, migration is both a cause and consequence of local vulnerabilities. While migration provides an opportunity for households to meet their immediate economic needs, it limits the ability of the community to foster longer-term economic development. At the same time, migration adversely affects the ability of the community to maintain food security due to lost labour and changing attitudes towards traditional ways of life among community members [Craven 2015].

5.8.2.2

Conflict

While climate change will not alone cause conflict, it is often acknowledged as having the potential to exacerbate or catalyse conflict in conjunction with other factors. Increased resource competition can aggravate the potential for migration to lead to conflict. When populations continue to increase, competition for resources will also increase, and resources will become even scarcer due to climate change [Hendrix and Glaser 2007]. In agriculture-dependent communities in low-income contexts, droughts have been found to increase the likelihood of violence and prolonged conflict at the local level, which eventually pose a threat to societal stability and peace [FAO et al. 2017]. In contrast, conflicts can also have diverging effects on agriculture due to land abandonment, resulting in forest growth, or agriculture expansion causing deforestation, for example, in Colombia [Landholm et al. 2019].

Several studies have explored the causal links among climate change, drought, impacts on agricultural production, livelihoods, and civil unrest in Syria from 2007–2010, but without agreement as to the role played by climate in subsequent migration [Kelley et al. 2015, 2017; Challinor et al. 2018; Selby et al. 2017; Hendrix 2018]. Contributing factors that have been examined include rainfall deficits, population growth, agricultural policies, and the influx of refugees that had placed burdens on the region’s water resources [Kelley et al. 2015]. Drought may have played a role as a trigger, as this drought was the longest and the most intense in the last 900 years [Cook et al. 2016; Mathbout et al. 2018]. Some studies linked the drought to widespread crop failure, but the climate hypothesis has been contested [Selby et al. 2017; Hendrix 2018]. Recent evidence shows that the severe drought triggered agricultural collapse and displacement of rural farm families, with approximately 300,000 families going to Damascus, Aleppo and other cities [Kelley et al. 2017].

Persistent drought in Morocco during the early 1980s resulted in food riots and contributed to an economic collapse [El-Said and Harrigan 2014]. A drought in Somalia that fuelled conflict through livestock price changes, establishing livestock markets as the primary channel of impact [Maystadt and Ecker 2014]. Cattle raiding as a normal means of restocking during drought in the Great Horn of Africa led to conflict [ICPAC and WFP 2017] whereas a region-wide drought in northern Mali in 2012 wiped out thousands of livestock and devastated the livelihoods of pastoralists, in turn swelling the ranks of armed rebel factions and forcing others to steal and loot for survival [Breisinger et al. 2015].

On the other hand, inter-annual adjustments in international trade can play an important role in shifting supplies from food surplus regions to regions facing food deficits which emerge as a consequence of extreme weather events, civil strife, and/or other disruptions [Baldos and Hertel 2015]. A more freely functioning global trading system is tested for its ability to deliver improved long run food security in 2050.

In summary, given increasing extreme events and global and cross-sectoral interconnectedness, the food system is at increasing risk of disruption, for example, via migration and conflict [high confidence]. {5.2.3, 5.2.4}

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