Interlinkages between desertification, land degradation, food security and GHG fluxes: synergies, trade-offs and integrated response options

Integrated response option

Description

Context and caveats

Supporting evidence

Increased food productivity

Increased food productivity arises when the output of food commodities increases per unit of input, e.g., per unit of land or water. It can be realised through many other interventions such as improved cropland, grazing land and livestock management.

Many interventions to increase food production, particularly those predicated on very large inputs of agro-chemicals, have a wide range of negative externalities leading to the proposal of sustainable intensification as a mechanism to deliver future increases in productivity that avoid these adverse outcomes. Intensification through additional input of nitrogen fertiliser, for example, would result in negative impacts on climate, soil, water and air pollution. Similarly,

if implemented in a way that over-exploits the land, signifi- cant negative impacts would occur, but if achieved through sustainable intensification, and used to spare land, it could reduce the pressure on land.

Cross-Chapter Box 6 in Chapter 5; Chapter 3

Balmford et al. 2018¹²⁸⁷; Burney et al. 2010¹²⁸⁸; Foley et al. 2011¹²⁸⁹; Garnett
et al. 2013¹²⁹⁰; Godfray et al. 2010¹²⁹¹; IPBES 2018¹²⁹²; Lal 2016¹²⁹³; Lamb et al. 2016¹²⁹⁴; Lobell et al. 2008¹²⁹⁵; Shcherbak et al. 2014¹²⁹⁶; Smith et al. 2013¹²⁹⁷; Tilman et al. 2011¹²⁹⁸

Improved cropland management

Improved cropland management is a collection of practices consisting of a) management of the crop: including high input carbon practices, for example, improved crop varieties, crop rotation, use of cover crops, perennial cropping systems, integrated production systems, crop diversification, agricultural biotechnology, b) nutrient management: including optimised fertiliser application rate, fertiliser type (organic manures, compost and mineral), timing, precision application, nitrification inhibitors, c) reduced tillage intensity and residue retention, d) improved water management: including drainage of waterlogged mineral soils and irrigation

of crops in arid/semi-arid conditions, e) improved rice management: including water management such
as mid-season drainage and improved fertilisation and residue management in paddy rice systems,

and f) biochar application.

Improved cropland management can reduce GHG emissions and create soil carbon sinks, though if poorly implemented, it could increase nitrous oxide and methane emissions from nitrogen fertilisers, crop residues and organic amendments. It can improve resilience of food crop production systems to climate change, and can be used to tackle desertification and land degradation by improving sustainable land management. It can also contribute
to food security by closing crop yield gaps to increase food productivity.

Chapter 4; Chapter 3; Chapter 2; Chapter 5

Bryan et al. 2009¹²⁹⁹; Chen et al. 2010¹³⁰⁰; Labrière et al. 2015¹³⁰¹; Lal 2011¹³⁰²; Poeplau and Don 2015¹³⁰³; Porter et al. 2014¹³⁰⁴; Smith 2008b¹³⁰⁵; Smith et al. 2014¹³⁰⁶; Tilman et al. 2011¹³⁰⁷

Integrated response option

Description

Context and caveats

Supporting evidence

Improved grazing land management

Improved grazing land management is a collection
of practices consisting of a) management of vegetation: including improved grass varieties/sward composition, deep rooting grasses, increased productivity, and nutrient management, b) animal management: including appropriate stocking densities fit to carrying capacity, fodder banks, and fodder diversification, and c) fire management: improved use of fire for sustainable grassland management, including fire prevention
and improved prescribed burning (see also fire management as a separate response option)
(Table 6.8).

Improved grazing land management can increase soil carbon sinks, reduce GHG emissions, improve the resilience of grazing lands to future climate change, help reduce desertification and land degradation by optimising stocking density and reducing overgrazing, and can enhance food security through improved productivity.

Chapter 2; Chapter 3; Chapter 4; Chapter 5; Section 6.4

Archer et al. 2011¹³⁰⁸; Briske et al. 2015¹³⁰⁹; Conant et al. 2017¹³¹⁰; Herrero et al. 2016¹³¹¹; Porter et al. 2014¹³¹²; Schwilch et al. 2014¹³¹³; Smith et al. 2014¹³¹⁴; Tighe et al. 2012¹³¹⁵

Improved livestock management

Improved livestock management is a collection of practices consisting of a) improved feed and dietary additives (e.g., bioactive compounds, fats), used to increase productivity and reduce emissions from enteric fermentation; b) breeding (e.g., breeds with higher productivity or reduced emissions from enteric fermentation), c) herd management, including decreasing neo-natal mortality, improving sanitary conditions, animal health and herd renewal, and diversifying animal species, d) emerging technologies (of which some are not legally authorised in several countries) such as propionate enhancers, nitrate and sulphate supplements, archaea inhibitors and archaeal vaccines, methanotrophs, acetogens, defaunation of the rumen, bacteriophages and probiotics, ionophores/antibiotics; and e) improved manure management, including manipulation of bedding and storage conditions, anaerobic digesters; biofilters, dietary change and additives, soil-applied and animal-fed nitrification inhibitors, urease inhibitors, fertiliser type, rate and timing, manipulation of manure application practices, and grazing management.

Improved livestock management can reduce GHG emissions, particularly from enteric methane and manure management. It can improve the resilience of livestock production systems to climate change by breeding better adapted livestock. It can help with desertification and land degradation, e.g., through use of more efficient and adapted breeds to allow reduced stocking densities. Improved livestock sector productivity can also increase food production.

Chapter 2; Chapter 3; Chapter 4; Chapter 5

Archer et al. 2011¹³¹⁶; Herrero et al. 2016¹³¹⁷; Miao et al. 2015¹³¹⁸; Porter et al. 2014¹³¹⁹; Rojas-Downing et al. 2017¹³²⁰; Smith et al. 2008¹³²¹, 2014¹³²²; Squires and Karami 2005¹³²³; Tighe et al. 2012¹³²⁴

Agroforestry

Agroforestry involves the deliberate planting of trees in croplands and silvo-pastoral systems.

Agroforestry sequesters carbon in vegetation and soils. The use of leguminous trees can enhance biological nitrogen fixation and resilience to climate change. Soil improvement and the provision of perennial vegetation can help to address desertification and land degradation. Agroforestry can increase agricultural productivity, with benefits for food security. Additionally, agroforestry can enable payments to farmers for ecosystem services and reduce vulnerability to climate shocks.

Antwi-Agyei et al. 2014¹³²⁵; Benjamin et al. 2018¹³²⁶; Guo et al. 2018¹³²⁷;
den Herder et al. 2017¹³²⁸; Mbow
et al. 2014a¹³²⁹; Mosquera-Losada
et al. 2018¹³³⁰; Mutuo et al. 2005¹³³¹; Nair and Nair 2014¹³³²; Ram et al. 2017¹³³³; Rosenstock et al. 2014¹³³⁴; Sain et al. 2017¹³³⁵; Santiago-Freijanes et al. 2018¹³³⁶; Sida et al. 2018¹³³⁷; Vignola et al. 2015¹³³⁸; Yirdaw et al. 2017¹³³⁹

Agricultural diversification

Agricultural diversification includes a set of agricultural practices and products obtained in the field that aim to improve the resilience of farmers to climate variability and climate change and to economic risks posed by fluctuating market forces. In general, the agricultural system is shifted from one based on low-value agricultural commodities to one that is more diverse, composed

of a basket of higher value-added products.

Agricultural diversification is targeted at adaptation
but could also deliver a small carbon sink, depending
on how it is implemented. It could reduce pressure on land, benefitting desertification, land degradation, food security and household income. However, the potential to achieve household food security is influenced by the market orientation of a household, livestock ownership, non-agricultural employment opportunities, and available land resources.

Birthal et al. 2015¹³⁴⁰; Campbell et al. 2014¹³⁴¹; Cohn et al. 2017¹³⁴²; Lambin and Meyfroidt 2011¹³⁴³; Lipper et al. 2014¹³⁴⁴; Massawe et al. 2016¹³⁴⁵; Pellegrini and Tasciotti 2014¹³⁴⁶; Waha et al. 2018¹³⁴⁷

Reduced grassland conversion to cropland

Grasslands can be converted to croplands by ploughing of grassland and seeding with crops. Since croplands have a lower soil carbon content than grasslands and are also more prone to erosion than grasslands, reducing conversion of grassland to croplands will prevent soil carbon losses by oxidation and soil loss through erosion. These processes can be reduced if the rate of grassland conversion to cropland is reduced.

Stabilising soils by retaining grass cover also improves resilience, benefitting adaptation, desertification and land degradation. Since conversion of grassland to cropland usually occurs to remedy food security challenges, food security could be adversely affected, since more land is required to produce human food from livestock products on grassland than from crops on cropland.

Chapter 3; Chapter 4; Chapter 5

Clark and Tilman 2017¹³⁴⁸; Lal 2001¹³⁴⁹; de Ruiter et al. 2017¹³⁵⁰; Poore and Nemecek 2018¹³⁵¹

Integrated response option

Description

Context and caveats

Supporting evidence

Integrated water management

Integrated water management is the process of
creating holistic strategies to promote integrated, efficient, equitable and sustainable use of water for agroecosystems. It includes a collection of practices including water-use efficiency and irrigation in arid/semi- arid areas, improvement of soil health through increases in soil organic matter content, and improved cropland management, agroforestry and conservation agriculture. Increasing water availability, and reliability of water for agricultural production, can be achieved by using different techniques of water harvesting, storage, and its judicious utilisation through farm ponds, dams, and community tanks in rainfed agriculture areas can benefit adaptation.

These practices can reduce aquifer and surface
water depletion, and prevent over-extraction, and the management of climate risks. Many technical innovations, e.g., precision water management, can have benefits for both adaptation and mitigation, although trade-offs are possible. Maintaining the same level of yield through use of site-specific water management-based approach could have benefits for both food security and mitigation.

Chapter 3; Chapter 4; Chapter 5

Brindha and Pavelic 2016¹³⁵²; Jat et al. 2016¹³⁵³; Jiang 2015¹³⁵⁴; Keesstra et al. 2018¹³⁵⁵; Liu et al. 2017¹³⁵⁶; Nejad 2013¹³⁵⁷; Rao et al. 2017b¹³⁵⁸; Shaw et al. 2014¹³⁵⁹; Sapkota et al. 2017¹³⁶⁰; Scott et al. 2011¹³⁶¹; Waldron et al. 2017¹³⁶²

Integrated response option

Description

Context and caveats

Supporting evidence

Forest management

Forest management refers to management interventions in forests for the purpose of climate change mitigation.
It includes a wide variety of practices affecting the growth of trees and the biomass removed, including improved regeneration (natural or artificial) and a better schedule, intensity and execution of operations (thinning, selective logging, final cut, reduced impact logging, etc.). Sustainable forest management is the stewardship and use of forests and forest lands in a way, and at a rate, that maintains their biodiversity, productivity, regeneration capacity, vitality and their potential to fulfil, now and

in the future, relevant ecological, economic and social functions, at local, national, and global levels, and that does not cause damage to other ecosystems.

Sustainable forest management can enhance the carbon stock in biomass, dead organic matter, and soil – while providing wood-based products to reduce emissions in other sectors through material and energy substitution.
A trade-off exists between different management strategies: higher harvest decreases the carbon in the forest biomass in the short term but increases the carbon in wood products and the potential for substitution effects. Sustainable forest management, also through close- to-nature silvicultural techniques, can potentially offer many co-benefits in terms of climate change mitigation, adaptation, biodiversity conservation, microclimatic regulation, soil erosion protection, coastal area protection and water and flood regulation. Forest management strategies aimed at increasing the biomass stock levels may have adverse side effects, such as decreasing the stand-level structural complexity, biodiversity and resilience to natural disasters. Forest management also affects albedo and evapotranspiration.

Chapter 2; Chapter 4

D’Amato et al. 2011¹³⁶³; Dooley
and Kartha 2018¹³⁶⁴; Ellison et al. 2017¹³⁶⁵; Erb et al. 2017¹³⁶⁶; Grassi
et al. 2018¹³⁶⁷; Griscom et al. 2017¹³⁶⁸; Jantz et al. 2014¹³⁶⁹; Kurz et al. 2016¹³⁷⁰; Locatelli 2011¹³⁷¹; Luyssaert et al. 2018¹³⁷²; Nabuurs et al. 2017¹³⁷³; Naudts et al. 2016¹³⁷⁴; Pingoud et al. 2018¹³⁷⁵; Putz et al. 2012¹³⁷⁶; Seidl et al. 2014¹³⁷⁷; Smith et al. 2014¹³⁷⁸; Smyth et al. 2014¹³⁷⁹; Stanturf et al. 2015¹³⁸⁰

Reduced deforestation and forest degradation

Reduced deforestation and forest degradation includes conservation of existing carbon pools in forest vegetation and soil by controlling the drivers of deforestation
(i.e., commercial and subsistence agriculture, mining, urban expansion) and forest degradation (i.e., overharvesting including fuelwood collection, poor harvesting practices, overgrazing, pest outbreaks, and extreme wildfires),

also through establishing protected areas, improving law enforcement, forest governance and land tenure, supporting community forest management and introducing forest certification.

Reducing deforestation and forest degradation is a major strategy to reduce global GHG emissions. The combination of reduced GHG emissions and biophysical effects results in a large climate mitigation effect, with benefits also at local level. Reduced deforestation preserves biodiversity and ecosystem services more efficiently and at lower costs than afforestation/reforestation. Efforts to reduce deforestation and forest degradation may have potential adverse side effects, for example, reducing availability of land for farming, restricting the rights and access of local people to forest resources (e.g., firewood), or increasing the dependence of local people to insecure external funding.

Chapter 2

Alkama and Cescatti 2016¹³⁸¹; Baccini et al. 2017¹³⁸²; Barlow et al. 2016¹³⁸³; Bayrak et al. 2016¹³⁸⁴; Caplow et al. 2011¹³⁸⁵; Curtis et al. 2018¹³⁸⁶; Dooley and Kartha 2018¹³⁸⁷; Griscom et al. 2017¹³⁸⁸; Hansen et al. 2013¹³⁸⁹; Hosonuma et al. 2012¹³⁹⁰; Houghton et al. 2015¹³⁹¹; Lewis et al. 2015¹³⁹²; Pelletier et al. 2016¹³⁹³; Rey Benayas et al. 2009¹³⁹⁴

Reforestation and forest restoration

Reforestation is the conversion to forest of land that has previously contained forests but that has been converted to some other use. Forest restoration refers to practices aimed at regaining ecological integrity in a deforested or degraded forest landscape. As such, it could fall under reforestation if it were re-establishing trees where they have been lost, or under forest management if it were restoring forests where not all trees have been lost.

For practical reasons, here forest restoration is treated together with reforestation.

Reforestation is similar to afforestation with respect
to the co-benefits and adverse side effects among
climate change mitigation, adaptation, desertification, land degradation and food security (see row on Afforestation below). Forest restoration can increase terrestrial carbon stocks in deforested or degraded forest landscapes and can offer many co-benefits in terms of increased resilience of forests to climate change, enhanced connectivity between forest areas and conservation of biodiversity hotspots.
Forest restoration may threaten livelihoods and local
access to land if subsistence agriculture is targeted.

Chapter 2

Dooley and Kartha 2018¹³⁹⁵; Ellison
et al. 2017¹³⁹⁶; Locatelli 2011¹³⁹⁷; Locatelli et al. 2015b¹³⁹⁸; Smith et al. 2014¹³⁹⁹; Stanturf et al. 2015¹⁴⁰⁰

Integrated response option

Description

Context and caveats

Supporting evidence

Afforestation

Afforestation is the conversion to forest of land that historically have not contained forests (see also ‘reforestation’).

Afforestation increases terrestrial carbon stocks but
can also change the physical properties of land surfaces, such as surface albedo and evapotranspiration with implications for local and global climate. In the tropics, enhanced evapotranspiration cools surface temperatures, reinforcing the climate benefits of CO₂ sequestration
in trees. At high latitudes and in areas affected by seasonal snow cover, the decrease in surface albedo after afforestation becomes dominant and causes an annual average warming that counteracts carbon benefits. Net biophysical effects on regional climate from afforestation is seasonal and can reduce the frequency of climate extremes, such as heat waves, improving adaptation to climate change and reducing the vulnerability of people and ecosystems. Afforestation helps to address land degradation and desertification, as forests tend to maintain water quality by reducing runoff, trapping sediments and nutrients, and improving groundwater recharge. However, food security could be hampered since an increase
in global forest area can increase food prices through land competition. Other adverse side effects occur when afforestation is based on non-native species, especially with the risks related to the spread of exotic fast-growing tree species. For example, exotic species can upset the balance of evapotranspiration regimes, with negative impacts on water availability, particularly in dry regions.

Chapter 2; Chapter 3; Chapter 4; Chapter 5

Alkama and Cescatti 2016¹⁴⁰¹; Arora and Montenegro 2011¹⁴⁰²; Bonan 2008¹⁴⁰³; Boysen et al. 2017a¹⁴⁰⁴; Brundu and Richardson 2016¹⁴⁰⁵; Cherubini et al. 2017¹⁴⁰⁶; Ciais et al. 2013¹⁴⁰⁷; Ellison et al. 2017¹⁴⁰⁸; Findell et al. 2017¹⁴⁰⁹; Medugu et al. 2010¹⁴¹⁰; Kongsager et al. 2016¹⁴¹¹; Kreidenweis et al. 2016¹⁴¹²; Lejeune et al. 2018¹⁴¹³; Li et al. 2015¹⁴¹⁴; Locatelli et al. 2015b¹⁴¹⁵; Perugini et al. 2017¹⁴¹⁶; Salvati et al. 2014¹⁴¹⁷; Smith et al. 2013¹⁴¹⁸, 2014¹⁴¹⁹; Trabucco et al. 2008¹⁴²⁰

Integrated response option

Description

Context and caveats

Supporting evidence

Increased soil organic carbon content

Practices that increase soil organic matter content include a) land-use change to an ecosystem with higher equilibrium soil carbon levels (e.g., from cropland to forest), b) management of the vegetation: including high input carbon practices, for example, improved varieties, rotations and cover crops, perennial cropping systems, biotechnology to increase inputs and recalcitrance of below ground carbon, c) nutrient management and organic material input to increase carbon returns to the soil, including: optimised fertiliser and organic material application rate, type, timing and precision application, d) reduced tillage intensity and residue retention, and
e) improved water management: including irrigation
in arid/semi-arid conditions.

Increasing soil carbon stocks removes CO₂ from the atmosphere and increases the water-holding capacity of
the soil, thereby conferring resilience to climate change and enhancing adaptation capacity. It is a key strategy for addressing both desertification and land degradation. There is some evidence that crop yields and yield stability increase by increased organic matter content, though some studies show equivocal impacts. Some practices to increase soil organic matter stocks vary in their efficacy. For example,
the impact of no-till farming and conservation agriculture on soil carbon stocks is often positive, but can be neutral
or even negative, depending on the amount of crop residues returned to the soil. If soil organic carbon stocks were increased by increasing fertiliser inputs to increase productivity, emissions of nitrous oxide from fertiliser use could offset any climate benefits arising from carbon sinks. Similarly, if any yield penalty is incurred from practices aimed at increasing soil organic carbon stocks (e.g., through extensification), emissions could be increased through indirect land-use change, and there could also be adverse side effects on food security.

Bestelmeyer and Briske 2012¹⁴²¹; Cheesman et al. 2016¹⁴²²; Frank et al. 2017¹⁴²³; Gao et al. 2018¹⁴²⁴; Hijbeek et al. 2017b¹⁴²⁵; Keesstra et al. 2016¹⁴²⁶; Lal 2016¹⁴²⁷; Lambin and Meyfroidt 2011¹⁴²⁸; de Moraes Sá et al. 2017¹⁴²⁹; Palm et al. 2014¹⁴³⁰; Pan et al. 2009¹⁴³¹; Paustian et al. 2016¹⁴³²; Powlson et al. 2014¹⁴³³, 2016¹⁴³⁴; Schjønning et al. 2018¹⁴³⁵; Smith et al. 2013¹⁴³⁶, 2014¹⁴³⁷, 2016c¹⁴³⁸; Soussana et al. 2019¹⁴³⁹; Steinbach and Alvarez 2006¹⁴⁴⁰; VandenBygaart 2016¹⁴⁴¹

Reduced soil erosion

Soil erosion is the removal of soil from the land surface by water, wind or tillage, which occurs worldwide but
it is particularly severe in Asia, Latin America and the Caribbean, and the Near East and North Africa. Soil erosion management includes conservation practices (e.g., the use of minimum tillage or zero tillage, crop rotations and cover crops, rational grazing systems), engineering-like practices (e.g., construction of terraces and contour cropping for controlling water erosion), or forest barriers and strip cultivation for controlling wind erosion. In eroded soils, the advance of erosion gullies and sand dunes can be limited by increasing plant cover, among other practices.

The fate of eroded soil carbon is uncertain, with some studies indicating a net source of CO₂ to the atmosphere and others suggesting a net sink. Reduced soil erosion has benefits for adaptation as it reduces vulnerability of soils to loss under climate extremes, increasing resilience to climate change. Some management practices implemented to control erosion, such as increasing ground cover, can reduce the vulnerability of soils to degradation/landslides, and prevention of soil erosion is a key measure used to tackle desertification. Because it protects the capacity of land to produce food, it also contributes positively to food security.

Chapter 3

Chen 2017; Derpsch et al. 2010¹⁴⁴²; FAO and ITPS 2015¹⁴⁴³; FAO 2015¹⁴⁴⁴; Garbrecht et al. 2015¹⁴⁴⁵; Jacinthe
and Lal 2001¹⁴⁴⁶; Lal and Moldenhauer 1987¹⁴⁴⁷; Lal 2001¹⁴⁴⁸; Lugato et al. 2016¹⁴⁴⁹; de Moraes Sá et al. 2017¹⁴⁵⁰; Poeplau and Don 2015¹⁴⁵¹; Smith et al. 2001¹⁴⁵², 2005¹⁴⁵³; Stallard 1998¹⁴⁵⁴; Van Oost et al. 2007¹⁴⁵⁵

Integrated response option

Description

Context and caveats

Supporting evidence

Reduced soil salinisation

Soil salinisation is a major process of land degradation that decreases soil fertility and affects agricultural production, aquaculture and forestry. It is a significant component
of desertification processes in drylands. Practices to reduce soil salinisation include improvement of water management (e.g., water-use efficiency and irrigation/ drainage technology in arid/semi-arid areas, surface

and groundwater management), improvement of soil health (through increase in soil organic matter content) and improved cropland, grazing land and livestock management, agroforestry and conservation agriculture.

Techniques to prevent and reverse soil salinisation may have small benefits for mitigation by enhancing carbon sinks. These techniques may benefit adaptation and food security by maintaining existing crop systems and closing yield gaps for rainfed crops. These techniques are central to reducing desertification and land degradation, since soil salinisation is a primary driver of both.

Section 3.6; Chapter 4; Chapter 5

Baumhardt et al. 2015¹⁴⁵⁶; Dagar et al. 2016¹⁴⁵⁷; Datta et al. 2000¹⁴⁵⁸; DERM 2011¹⁴⁵⁹; Evans and Sadler 2008¹⁴⁶⁰; He et al. 2015¹⁴⁶¹; D’Odorico et al. 2013¹⁴⁶²; Kijne et al. 1988¹⁴⁶³; Qadir et al. 2013¹⁴⁶⁴; Rengasamy 2006¹⁴⁶⁵; Singh 2009¹⁴⁶⁶; UNCTAD 2011¹⁴⁶⁷; Wong et al. 2010¹⁴⁶⁸

Reduced soil compaction

Reduced soil compaction mainly includes agricultural techniques (e.g., crop rotations, control of livestock density) and control of agricultural traffic.

Techniques to reduce soil compaction have variable impacts on GHG emissions but may benefit adaptation by improving soil climatic resilience. Since soil compaction is a driver of both desertification and land degradation, a reduction of soil compaction could benefit both. It could also help close yield gaps in rainfed crops.

Chamen et al. 2015¹⁴⁶⁹; Epron et al. 2016¹⁴⁷⁰; FAO and ITPS 2015¹⁴⁷¹; Hamza and Anderson 2005¹⁴⁷²; Soane and Van Ouwerkerk 1994¹⁴⁷³; Tullberg et al. 2018¹⁴⁷⁴

Biochar addition to soil

The use of biochar, a solid product of the pyrolysis process, as a soil amendment increases the water-holding capacity of soil. It may therefore provide better access
to water and nutrients for crops and other vegetation types (so can form part of cropland, grazing land and forest management).

The use of biochar increases carbon stocks in the soil. It
can enhance yields in the tropics (but less so in temperate regions), thereby benefitting both adaptation and food security. Since it can improve soil water-holding capacity and nutrient-use efficiency, and can ameliorate heavy metal pollution and other impacts, it can benefit desertification and land degradation. The positive impacts could be tempered by additional pressure on land if large quantities of biomass are required as feedstock for biochar production.

Chapter 2; Chapter 3; Chapter 4; Chapter 5

Jeffery et al. 2017¹⁴⁷⁵; Smith 2016¹⁴⁷⁶; Sohi 2012¹⁴⁷⁷; Woolf et al. 2010¹⁴⁷⁸

Integrated response option

Description

Context and caveats

Supporting evidence

Fire management

Fire management is a land management option aimed at safeguarding life, property and resources through the prevention, detection, control, restriction and suppression of fire in forest and other vegetation. It includes the improved use of fire for sustainable forestry management, including wildfire prevention and prescribed burning. Prescribed burning is used to reduce the risk of large, uncontrollable fires in forest areas, and controlled burning is among the most effective and economic methods of reducing fire danger and stimulating natural reforestation under the forest canopy and after clear felling.

The frequency and severity of large wildfires have increased around the globe in recent decades, which has impacted on forest carbon budgets. Fire can cause various GHG emissions such as carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), and others such as carbon monoxide (CO), volatile organic carbon, and smoke aerosols. Fire management can reduce GHG emissions and can reduce haze pollution, which has significant health and economic impacts. Fire management helps to prevent soil erosion and land degradation and is used in rangelands to conserve biodiversity and to enhance forage quality.

Chapter 2; Cross-Chapter Box 3 in Chapter 2

Esteves et al. 2012¹⁴⁷⁹; FAO 2006¹⁴⁸⁰;
Lin et al. 2017¹⁴⁸¹; O’Mara 2012¹⁴⁸²; Rulli et al. 2006¹⁴⁸³; Scasta et al. 2016¹⁴⁸⁴; Seidl et al. 2014¹⁴⁸⁵; Smith et al. 2014¹⁴⁸⁶; Tacconi 2016¹⁴⁸⁷; Valendik et al. 2011¹⁴⁸⁸; Westerling et al. 2006¹⁴⁸⁹; Whitehead et al. 2008¹⁴⁹⁰; Yong and Peh 2016¹⁴⁹¹

Reduced landslides and natural hazards

Landslides are mainly triggered by human activity
(e.g., legal and illegal mining, fire, deforestation) in combination with climate. Management of landslides and natural hazards (e.g., floods, storm surges, droughts) is based on vegetation management (e.g., afforestation) and engineering works (e.g., dams, terraces, stabilisation and filling of erosion gullies).

Management of landslides and natural hazards is important for adaptation and is a crucial intervention for managing land degradation, since landslides and natural hazards are among the most severe degradation processes. In countries where mountain slopes are planted with food crops, reduced landslides will help deliver benefits for food security. Most deaths caused due to different disasters have occurred in developing countries, where poverty, poor education and health facilities and other aspects of development, increase exposure, vulnerability and risk.

Noble et al. 2014¹⁴⁹²;
Arnáez J et al. 2015¹⁴⁹³; Campbell 2015¹⁴⁹⁴; FAO and ITPS 2015¹⁴⁹⁵; Gariano and Guzzetti 2016¹⁴⁹⁶; Mal et al. 2018¹⁴⁹⁷

Reduced pollution including acidification

Management of air pollution is connected to climate change by emission sources of air-polluting materials and their impacts on climate, human health and ecosystems, including agriculture. Acid deposition is one of the many consequences of air pollution, harming trees and other vegetation, as well as being a significant driver of land degradation. Practices that reduce acid deposition include prevention of emissions of nitrogen oxides (NOx) and sulphur dioxide (SO2), which also reduce GHG emissions and other short-lived climate pollutants (SLCPs). Reductions of SLCPs reduce warming in the near term and the overall rate of warming, which can be crucial for plants that are sensitive to even small increases in temperature.

There are a few potential adverse side effects of reduction in air pollution to carbon sequestration in terrestrial ecosystems, because some forms of air pollutants can enhance crop productivity by increasing diffuse sunlight, compared to direct sunlight. Reactive nitrogen deposition could also enhance CO₂ uptake in boreal forests and increase soil carbon pools to some extent. Air pollutants have different impacts on climate depending primarily on the composition, with some aerosols (and clouds seeded by them) increasing the reflection of solar radiation to space leading to net cooling, while others (e.g., black carbon and tropospheric ozone) having a net warming effect. Therefore, control of these different pollutants will have both positive and negative impacts on climate mitigation.

Chapter 2

Anderson et al. 2017¹⁴⁹⁸; Chum et al. 2011¹⁴⁹⁹; Carter et al. 2015¹⁵⁰⁰; Coakley 2005¹⁵⁰¹; Maaroufi et al. 2015¹⁵⁰²; Markandya et al. 2018¹⁵⁰³; Melamed and Schmale 2016¹⁵⁰⁴; Mostofa et al. 2016¹⁵⁰⁵; Nemet et al. 2010¹⁵⁰⁶; Ramanathan et al. 2001¹⁵⁰⁷; Seinfeld and Pandis¹⁵⁰⁸; Smith et al. 2015¹⁵⁰⁹; UNEP 2017¹⁵¹⁰; UNEP and WMO 2011¹⁵¹¹; Wild et al. 2012¹⁵¹²; Xu et al. 2013¹⁵¹³; Xu and Ramanathan 2017¹⁵¹⁴

Integrated response option

Description

Context and caveats

Supporting evidence

Reduced pollution including acidification continued

Management of harmful air pollutants such as fine particulate matter (PM2.5) and ozone (O3) also mitigate
the impacts of incomplete fossil fuel combustion and GHG emissions. In addition, management of pollutants such as tropospheric O3 has beneficial impacts on food production, since O3 decreases crop production. Control of urban and industrial air pollution would also mitigate the harmful effects of pollution and provide adaptation co-benefits via improved human health. Management of pollution contrib- utes to aquatic ecosystem conservation since controlling air pollution, rising atmospheric CO₂ concentrations, acid deposition, and industrial waste will reduce acidification of marine and freshwater ecosystems.

Management of invasive species/ encroachment

Agriculture and forests can be diverse, but often

much of the diversity is non-native. Invasive species

in different biomes have been introduced intentionally

or unintentionally through export of ornamental plants

or animals, and through the promotion of modern

agriculture and forestry. Non-native species tend to

be more numerous in larger than in smaller human-

modified landscapes (e.g., over 50% of species in an

urbanised area or extensive agricultural fields can be

non-native). Invasive alien species in the USA cause major

environmental damage amounting to almost 120 billion

–1
USD yr . There are approximately 50,000 foreign species

and the number is increasing. About 42% of the species on the Threatened or Endangered species lists are at risk primarily because of alien-invasive species. Invasive species can be managed through manual clearance of invasive species, while in some areas, natural enemies of the invasive species are introduced to control them.

Exotic species are used in forestry where local indigenous forests cannot produce the type, quantity and quality of forest products required. Planted forests of exotic tree species make significant contributions to the economy and provide multiple products and Nature’s Contributions to People. In general, exotic species are selected to have higher growth rates than native species and produce more wood per unit of area and time. In 2015, the total area of planted forest with non-native tree species was estimated

2
to be around 0.5 Mkm . Introduced species were dominant

in South America, Oceania and Eastern and Southern Africa, where industrial forestry is dominant. The use of exotic tree species has played an important role in the production of roundwood, fibre, firewood and other forest products. The challenge is to manage existing and future plantation forests of alien trees to maximise current benefits, while minimising present and future risks and negative impacts, and without compromising future benefits. In many countries or regions, non-native trees planted for production or other purposes often lead to sharp conflicts of interest when they become invasive, and to negative impacts on Nature’s Contributions to People and nature conservation.

Brundu and Richardson 2016¹⁵¹⁵; Cossalter and Pye-Smith 2003¹⁵¹⁶; Dresner et al. 2015¹⁵¹⁷; Payn et al. 2015¹⁵¹⁸; Pimentel et al. 2005¹⁵¹⁹; Vilà et al. 2011¹⁵²⁰

Restoration and reduced conversion of coastal wetlands

Coastal wetland restoration involves restoring degraded/ damaged coastal wetlands, including mangroves, salt marshes and seagrass ecosystems.

Coastal wetland restoration and avoided coastal wetland impacts have the capacity to increase carbon sinks and can provide benefits by regulating water flow and preventing downstream flooding. Coastal wetlands provide a natural defence against coastal flooding and storm surges by dissipating wave energy, reducing erosion and by helping to stabilise shore sediments. Since large areas of global coastal wetlands are degraded, restoration could provide benefits land degradation. Since some areas of coastal wetlands are used for food production, restoration could displace food production and damage local food supply (Section 6.3.4), though some forms (e.g., mangrove restoration)

can improve local fisheries.

Griscom et al. 2017¹⁵²¹; Lotze et al. 2006¹⁵²²; Munang et al. 2014¹⁵²³; Naylor et al. 2000¹⁵²⁴

Restoration and reduced conversion of peatlands

Peatland restoration involves restoring degraded/ damaged peatlands, which both increases carbon sinks, but also avoids ongoing CO₂ emissions from degraded peatlands. So, as well as protecting biodiversity, it both prevents future emissions and creates a sink.

Avoided peat impacts and peatland restoration can provide significant mitigation, though restoration can lead to an increase in methane emissions, particularly in nutrient rich fens. There may also be benefits for climate adaptation by regulating water flow and preventing downstream flooding. Considering that large areas of global peatlands are degraded, peatland restoration is a key tool in addressing land degradation. Since large areas of tropical peatlands and some northern peatlands have been drained and cleared for food production, their restoration could displace food production and damage local food supply, potentially leading to adverse impacts on food security locally, though the global impact would be limited due to the relatively small areas affected.

Griscom et al. 2017¹⁵²⁵; Jauhiainen et al. 2008¹⁵²⁶; Limpens et al. 2008¹⁵²⁷; Munang et al. 2014¹⁵²⁸

Integrated response option

Description

Context and caveats

Supporting evidence

Biodiversity conservation

Biodiversity conservation refers to practices aimed
at maintaining components of biological diversity. It includes conservation of ecosystems and natural habitats, maintenance and recovery of viable populations of species in their natural surroundings (in-situ conservation) and, in the case of domesticated or cultivated species,
in the surroundings where they have developed their distinctive properties outside their natural habitats (ex-situ conservation). Examples of biodiversity conservation measures are establishment of protected areas to achieve specific conservation objectives, preservation of biodiversity hotspots, land management to recover natural habitats, interventions to expand or control selective plant or animal species in productive lands or rangelands (e.g., rewilding).

Biodiversity conservation measures interact with the
climate system through many complex processes, which
can have either positive or negative impacts. For example, establishment of protected areas can increase carbon storage in vegetation and soil, and tree planting to promote species richness and natural habitats can enhance carbon uptake capacity of ecosystems. Management of
wild animals can influence climate via emissions of GHGs (from anaerobic fermentation of plant materials in the rumen), impacts on vegetation (via foraging), changes in fire frequency (as grazers lower grass and vegetation densities as potential fuels), and nutrient cycling and transport
(by adding nutrients to soils). Conserving and restoring megafauna in northern regions also prevents thawing of permafrost and reduces woody encroachment, thus avoiding methane emissions and increases in albedo. Defaunation affects carbon storage in tropical forests and savannahs. In the tropics, the loss of mega-faunal frugivores is estimated be responsible for up to 10% reduction in carbon storage
of global tropical forests. Frugivore rewilding programmes in the tropics are seen as carbon sequestration options that can be equally effective as tree planting schemes. Biodiversity conservation measures generally favour adaptation,
but can interact with food security, land degradation or desertification. Protected areas for biodiversity reduce
the land available for food production, and abundancies
of some species (such as large animals) can influence
land degradation processes by grazing, trampling
and compacting soil surfaces, thereby altering surface temperatures and chemical reactions affecting sediment and carbon retention.

Bello et al. 2015¹⁵²⁹; Campbell et al. 2008¹⁵³⁰; Cromsigt et al. 2018¹⁵³¹; Kapos et al. 2008¹⁵³²; Osuri et al. 2016¹⁵³³; Schmitz et al. 2018¹⁵³⁴; Secretariat of the Convention on Biological Diversity 2008¹⁵³⁵

Integrated response option

Description

Context and caveats

Supporting evidence

Enhanced weathering of minerals

The enhanced weathering of minerals that naturally absorb CO₂ from the atmosphere has been proposed as a CDR technology with a large mitigation potential. The rocks are ground to increase the surface area and the ground minerals are then applied to the land where they absorb atmospheric CO2.

Enhanced mineral weathering can remove atmospheric carbon dioxide (CO₂). Since ground minerals can increase pH, there could be some benefits for efforts to prevent or reverse land degradation where acidification is the driver of degrada- tion. Since increasing soil pH in acidified soils can increase productivity, the same effect could provide some benefit for food security. Minerals used for enhanced weathering need to be mined, and mining has large impacts locally, though the total area mined is likely to be small on the global scale.

Beerling et al. 2018¹⁵³⁶; Lenton 2010¹⁵³⁷; Schuiling and Krijgsman 2006¹⁵³⁸; Smith et al. 2016a¹⁵³⁹; Taylor et al. 2016¹⁵⁴⁰

Bioenergy and bioenergy with carbon capture and storage (BECCS)

Bioenergy production can mitigate climate change
by delivering an energy service, therefore avoiding combustion of fossil energy. It is the most common renewable energy source used in the world today and has a large potential for future deployment (see Cross- Chapter Box 7 in this chapter). BECCS entails the use of bioenergy technologies (e.g., bioelectricity or biofuels) in combination with CO₂ capture and storage (see also Glossary). BECCS simultaneously provides energy and can reduce atmospheric CO₂ concentrations (Chapter 2; Cross-Chapter Box 7 in this chapter) for a discussion of potentials and atmospheric effects); thus, BECCS
is considered a CDR technology. While several BECCS demonstration projects exist, it has yet to be deployed at scale. Bioenergy and BECCS are widely-used in many future scenarios as a climate change mitigation option in the energy and transport sector, especially those scenarios aimed at a stabilisation of global climate
at 2°C or less above pre-industrial levels.

Bioenergy and BECCS can compete for land and water with other uses. Increased use of bioenergy and BECCS can result in large expansion of cropland area, significant deforestation, and increased irrigation water use and water scarcity. Large- scale use of bioenergy can result in increased food prices and can lead to an increase in the population at risk of hunger. As a result of these effects, large-scale bioenergy and BECCS can have negative impacts for food security. Interlinkages

of bioenergy and BECCS with climate change adaptation, land degradation, desertification, and biodiversity are highly dependent on local factors such as the type of energy crop, management practice, and previous land use. For example, intensive agricultural practices aiming to achieve high crop yields, as is the case for some bioenergy systems, may have significant effects on soil health, including depletion of
soil organic matter, resulting in negative impacts on land degradation and desertification. However, with low inputs of fossil fuels and chemicals, limited irrigation, heat/drought tolerant species, using marginal land, biofuel programmes can be beneficial to future adaptation of ecosystems.

Cross-Chapter Box 7 in Chapter 6

IPCC SR15 (IPCC 2018); Chapter 2; Chapter 4; Section 6.4; Chapter 7

Baker et al. 2019¹⁵⁴¹; Calvin et al. 2014¹⁵⁴²; Chaturvedi et al. 2013¹⁵⁴³; Chum et al. 2011¹⁵⁴⁴; Clarke et al. 2014¹⁵⁴⁵; Correa
et al. 2017¹⁵⁴⁶; Creutzig et al. 2015¹⁵⁴⁷; Dasgupta et al. 2014¹⁵⁴⁸; Don et al. 2012¹⁵⁴⁹; Edelenbosch et al. 2017¹⁵⁵⁰; IPCC 2012¹⁵⁵¹; Favero and Mendelsohn 2014¹⁵⁵²; FAO 2011a¹⁵⁵³; Fujimori et al. 2019¹⁵⁵⁴; Fuss et al. 2016¹⁵⁵⁵, 2018¹⁵⁵⁶; Hejazi et al. 2015¹⁵⁵⁷; Kemper 2015¹⁵⁵⁸; Kline et al. 2017¹⁵⁵⁹; Lal 2014; Lotze-Campen et al. 2013¹⁵⁶⁰; Mello et al. 2014¹⁵⁶¹; Muratori et al. 2016¹⁵⁶²; Noble et al. 2014¹⁵⁶³; Obersteiner et al. 2016¹⁵⁶⁴;

Integrated response option

Description

Context and caveats

Supporting evidence

Bioenergy and bioenergy with carbon capture and storage (BECCS) continued

Planting bioenergy crops, like perennial grasses, on degraded land can increase soil carbon and ecosystem quality (including biodiversity), thereby helping to preserve soil quality, reverse land degradation, prevent desertification processes, and reduce food insecurity. These effects depend on the scale of deployment, the feedstock, the prior land use, and which other response options are included (see Section 6.4.4.2). Large-scale production of bioenergy can require significant amounts of land, increasing potential pressures for land conversion and land degradation. Low levels of bioenergy deployment require less land, leading
to smaller effects on forest cover and food prices; however, these land requirements could still be substantial. In terms of feedstocks, in some regions, they may not need irrigation, and thus would not compete for water with food crops. Additionally, the use of residues or microalgae could limit competition for land and biodiversity loss; however, residues could result in land degradation or decreased soil organic carbon. Whether woody bioenergy results in increased competition for land or not is disputed in the literature,
with some studies suggesting reduced competition and others suggesting enhanced competition. One study noted that this effect changes over time, with complementarity between woody bioenergy and forest carbon sequestration in the near-term, but increased competition for land with afforestation/reforestation in the long term. Additionally, woody bioenergy could also result in land degradation.

Popp et al. 2011b¹⁵⁶⁵, 2014¹⁵⁶⁶, 2017¹⁵⁶⁷; Riahi et al. 2017¹⁵⁶⁸; Robertson
et al. 2017a¹⁵⁶⁹; Sánchez et al. 2017¹⁵⁷⁰; Searchinger et al. 2018¹⁵⁷¹; Sims et al. 2014¹⁵⁷²; Slade et al. 2014¹⁵⁷³; Smith et al. 2016c¹⁵⁷⁴; Tian et al. 2018¹⁵⁷⁵; Torvanger 2018¹⁵⁷⁶; Van Vuuren et al. 2011¹⁵⁷⁷, 2015¹⁵⁷⁸, 2016¹⁵⁷⁹; Wise et al. 2015¹⁵⁸⁰

Integrated response option

Description

Context and caveats

Supporting evidence

Dietary change

Sustainable healthy diets represent a range of dietary changes to improve human diets, to make them healthy in terms of the nutrition delivered, and also (economically, environmentally and socially) sustainable. A ‘contract and converge’ model of transition to sustainable healthy diets would involve a reduction in over-consumption (particularly of livestock products) in over-consuming populations, with increased consumption of some food groups in populations where minimum nutritional needs are not met. Such a conversion could result in a decline
in undernourishment, as well as reduction in the risk of morbidity and mortality due to over-consumption.

A dietary shift away from meat can reduce GHG emissions, reduce cropland and pasture requirements, enhance biodiversity protection, and reduce mitigation costs. Additionally, dietary change can both increase potential for other land-based response options and reduce the need for them by freeing land. By decreasing pressure on land, demand reduction through dietary change could also allow for decreased production intensity, which could reduce soil erosion and provide benefits to a range of other environmental indicators such as deforestation and decreased use of fertiliser (nitrogen and phosphorus), pesticides, water and energy, leading to potential benefits for adaptation, desertification, and land degradation.

Chapter 5; Section 6.4.4.2

Aleksandrowicz et al. 2016; Bajželj et al. 2014a; Bonsch
et al. 2016; Erb et al. 2016; Godfray et al. 2010; Haberl et al. 2011; Havlík et al. 2014; Muller et al. 2017; Smith et al. 2013; Springmann et al. 2018; Stehfest et al. 2009; Tilman and Clark 2014; Wu et al. 2019

Reduced post- harvest losses

Approximately one-third of the food produced for
human consumption is wasted in post-production operations. Most of these losses are due to poor storage management. Post-harvest food losses underlie the food system’s failure to equitably enable accessible and affordable food in all countries. Reduced post-harvest food losses can improve food security in developing countries (while food loss in developed countries mostly occurs at the retail/consumer stage). The key drivers for post-harvest waste in developing countries are structural and infrastructure deficiencies. Thus, reducing food waste at the post-harvest stage requires responses that process, preserve and, where appropriate, redistribute food to where it can be consumed immediately.

Differences exist between farm food waste reduction technologies between small-scale agricultural systems and large-scale agricultural systems. A suite of options includes farm-level storage facilities, trade or exchange processing technologies including food drying, on-site farm processing for value addition, and improved seed systems. For large- scale agri-food systems, options include cold chains for preservation, processing for value addition and linkages to value chains that absorb the harvests almost instantly into the supply chain. In addition to the specific options to reduce food loss and waste, there are more systemic possibilities related to food systems. Improving and expanding the ‘dry chain’ can significantly reduce food losses at the household level. Dry chains are analogous to the cold chain and refers to the ‘initial dehydration of durable commodities to levels preventing fungal growth’ followed by storage in moisture- proof containers. Regional and local food systems are now being promoted to enable production, distribution, access and affordability of food. Reducing post-harvest losses has the potential to reduce emissions and could simultaneously reduce food costs and increase availability. The perishability and safety of fresh foods are highly susceptible to temperature increase.

Chapter 5

Ansah et al. 2017; Bajželj
et al. 2014b; Billen et al. 2018; Bradford et al. 2018; Chaboud and Daviron 2017; Göbel et al. 2015; Gustavsson et al. 2011; Hengsdijk and de Boer 2017; Hodges et al. 2011; Ingram et al. 2016; Kissinger et al. 2018; Kumar and Kalita 2017; Ritzema et al. 2017; Sheahan and Barrett 2017a; Wilhelm et al. 2016)

Reduced food waste (consumer or retailer)

Since approximately 9–30% of all food is wasted, reducing food waste can reduce pressure on land (see also reducing post-harvest losses).

Reducing food waste could lead to a reduction in cropland area and GHG emissions, resulting in benefits for mitigation. By decreasing pressure on land, food waste reduction could allow for decreased production intensity, which could reduce soil erosion and provide benefits to a range of other environmental indicators such as deforestation and decreases in use of fertiliser (N and P), pesticides, water and energy, leading to potential benefits for adaptation, desertification, and land degradation.

Alexander et al. 2016; Bajželj et al. 2014b; Gustavsson et al. 2011; Kummu et al. 2012; Muller et al. 2017; Smith et al. 2013; Vermeulen et al. 2012b

Material substitution

Material substitution involves the use of wood or agricultural biomass (e.g., straw bales) instead of fossil fuel-based materials (e.g., concrete, iron, steel, aluminium) for building, textiles or other applications.

Material substitution reduces carbon emissions – both because the biomass sequesters carbon in materials while re-growth of forests can lead to continued sequestration, and because it reduces the demand for fossil fuels, delivering a benefit for mitigation. However, a potential trade-off exists between conserving carbon stocks and using forests for wood products. If the use of material for substitution was large enough to result in increased forest area, then the adverse side effects for adaptation and food security would be similar to that of reforestation and afforestation. In addition, some studies indicate that wooden buildings,

if properly constructed, could reduce fire risk compared
to steel, creating a co-benefit for adaptation. The effects
of material substitution on land degradation depend on management practice; some forms of logging can lead to increased land degradation. Long-term forest management with carbon storage in long-lived products also results in atmospheric CO2 removal.

Chapter 4

Dugan et al. 2018; Eriksson et al. 2012; Gustavsson et al. 2006; Iordan et al. 2018; Kauppi et al. 2018; Kurz et al. 2016; Leskinen et al. 2018; McLaren 2012; Miner 2010; Oliver and Morecroft 2014; Ramage et al. 2017; Sathre and O’Connor 2010; Smyth et al. 2014

Integrated response option

Description

Context and caveats

Supporting evidence

Sustainable sourcing

Sustainable sourcing includes approaches to ensure that the production of goods is done in a sustainable way, such as through low-impact agriculture, zero-deforestation supply chains, or sustainably harvested forest products. Currently around 8% of global forest area has been certified in some manner, and 25% of global industrial roundwood comes from certified forests. Sustainable sourcing also aims to enable producers to increase their percentage of the final value of commodities. Adding value to products requires improved innovation, coordination and efficiency in the food supply chain, as well as labelling to meet consumer demands. As such, sustainable sourcing is an approach that combines both supply- and demand- side management. Promoting sustainable and value- added products can reduce the need for compensatory extensification of agricultural areas and is a specific commitment of some sourcing programmes (such as forest certification programmes). Table 7.3 (Chapter 7) provides examples of the many sustainable sourcing programmes now available globally.

Sustainable sourcing is expanding but accounts for only
a small fraction of overall food and material production; many staple food crops do not have strong sustainability standards. Sustainable sourcing provides potential benefits for both climate mitigation and adaptation by reducing drivers of unsustainable land management, and by diversifying and increasing flexibility in the food system to climate stressors and shocks. Sustainable sourcing can lower expenditure for food processors and retailers by reducing losses. Adding value to products can extend a producer’s marketing season and provide unique opportunities to capture niche markets, thereby increasing their adaptive capacity to climate change. Sustainable sourcing can also provide significant benefits for food security, while simultaneously creating economic alternatives for the poor. Sustainable sourcing programmes often also have positive impacts on the overall efficiency of the food supply chain and can create closer and more direct links between producers and consumers. In some cases, processing of value-added products could lead to higher emissions or demand for resources in the food system, potentially leading to small adverse impacts on
land degradation and desertification challenges.

Chapter 2; Chapter 3; Chapter 5; Section 6.4

Accorsi et al. 2017; Bajželj et al. 2014a; Bustamante et al. 2014; Clark and Tilman 2017; Garnett 2011; Godfray et al. 2010; Hertel 2015; Ingram et al. 2016; James and James 2010; Muller et al. 2017; Springer et al. 2015; Tayleur et al. 2017; Tilman and Clark 2014

Management of supply chains

Management of supply chains include a set of polycentric governance processes focused on improving efficiency and sustainability across the supply chain for each product, to reduce climate risk and profitably reduce emissions. Trade-driven food supply chains are becoming increasingly complex and are contributing to emissions. Improved management of supply chains can include

1) better food transport and increasing the economic value or reduce risks of commodities through production processes (e.g., packaging, processing, cooling, drying, extracting) and 2) improved policies for stability of food supply, as globalised food systems and commodity markets are vulnerable to food price volatility. The 2007–2008 food price shocks negatively affected food security for millions, most severely in Sub-Saharan Africa. Increasing the stability of food supply chains is a key goal to increase food security, given that climate change threatens to lead to more production shocks in the future.

Successful implementation of supply chain management practices is dependent on organisational capacity, the agility and flexibility of business strategies, the strengthening
of public-private policies and effectiveness of supply- chain governance. Existing practices include a) greening supply chains (e.g., utilising products and services with

a reduced impact on the environment and human health),
b) adoption of specific sustainability instruments among agri-food companies (e.g., eco-innovation practices ),
c) adopting emission accounting tools (e.g., carbon and water foot-printing), and d) implementing ‘demand forecasting’ strategies (e.g., changes in consumer preference for ‘green’ products). In terms of food supply, measures to improve stability in traded markets can include i) financial and trade policies, such as reductions on food taxes and import tariffs, (ii) shortening food supply chains (SFSCs), (iii) increasing food production, (iv) designing alternative distribution networks, (v) increasing food market transparency and reducing speculation in futures markets, (vi) increasing storage options, and (vii) increasing subsidies and food-based safety nets.

Chapter 5

Barthel and Isendahl 2013; Haggblade et al. 2017; Lewis and Witham 2012; Michelini et al. 2018; Minot 2014; Mundler and Rumpus 2012; Tadasse et al. 2016; Wheeler and von Braun 2013; Wilhelm et al. 2016; Wodon and Zaman 2010; World Bank 2011

Enhanced urban food systems

Urban areas are becoming the principal territories
for intervention in improving food access through innovative strategies that aim to reduce hunger and improve livelihoods. Interventions include urban and peri-urban agriculture and forestry and local food policy and planning initiatives such as Food Policy Councils and city-region-wide regional food strategies. Such systems have demonstrated inter-linkages of the city and its citizens with surrounding rural areas to create sustainable, and more nutritious food supplies for the city, while improving the health status of urban dwellers, reducing pollution levels, adapting to and mitigating climate change, and stimulating economic development. Options include support for urban and peri-urban agriculture, green infrastructure (e.g., green roofs), local markets, enhanced social (food) safety

nets and development of alternative food sources and technologies, such as vertical farming.

Urban territorial areas have a potential to reduce GHG emissions through improved food systems to reduce vehicle miles of food transportation, localised carbon capture and food waste reduction. The benefits of urban food forests that are intentionally planted woody perennial food-producing species, are also cited for their carbon sequestration potentials. However, new urban food systems may have diverse and unexpected adverse side effects with climate systems, such as lower efficiencies

in food supply and higher costs than modern large-scale agriculture. Diversifying markets, considering value-added products in the food supply system may help to improve food security by increasing its economic performance and revenues to local farmers.

Akhtar et al. 2016; Benis and Ferrão 2017; Brinkley et al. 2013; Chappell et al. 2016; Dubbeling 2014; Goldstein et al. 2016; Kowalski and Conway 2018; Lee-Smith 2010; Barthel and Isendahl 2013; Lwasa et al. 2014, 2015; Revi et al. 2014; Specht et al. 2014; Tao et al. 2015

Integrated response option

Description

Context and caveats

Supporting evidence

Improved food processing and retailing

Improved food processing and retailing involves
several practices related to a) greening supply chains
(e.g., utilising products and services with a reduced impact on the environment and human health), b) adoption
of specific sustainability instruments among agri-food companies (e.g., eco-innovation practices), c) adopting emission accounting tools (e.g., carbon and water foot-printing), d) implementing ‘demand forecasting’ strategies (e.g., changes in consumer preference for ‘green’ products) and, e) supporting polycentric supply- chain governance processes.

Improved food processing and retailing can provide benefits for climate mitigation since GHG-friendly foods can reduce agri-food GHG emissions from transportation, waste and energy use. In cases where climate extremes and natural disasters disrupt supply chain networks, improved food processing and retailing can benefit climate adaptation by buffering the impacts of changing temperature and rainfall patterns on upstream agricultural production. It can provide benefits for food security by supporting healthier diets and reducing food loss and waste. Successful implementation

is dependent on organisational capacity, the agility and flexibility of business strategies, the strengthening of public- private policies and effectiveness of supply-chain governance.

Chapter 2; Chapter 5

Avetisyan et al. 2014; Garnett et al. 2013; Godfray et al. 2010; Mohammadi et al. 2014; Porter et al. 2016; Ridoutt et al. 2016; Song et al. 2017

Improved energy use in food systems

Agriculture’s energy efficiency can be improved to reduce the dependency on non-renewable energy sources. This can be realised either by decreased energy inputs, or through increased outputs per unit
of input. In some countries, managerial inefficiency (rather than a technology gap) is the main source for energy-efficiency loss. Heterogenous patterns of energy efficiency exist at the national scale and promoting energy-efficient technologies along with managerial capacity development can reduce the gap and provide large benefits for climate adaptation. Improvements in carbon monitoring and calculation techniques such as the foot-printing of agricultural products can enhance energy-efficiency transition management and uptake in agricultural enterprises.

Transformation to low-carbon technologies such as renewable energy and energy efficiency can offer opportunities for significant climate change mitigation,
for example, by providing a substitute to transport fuel
that could benefit marginal agricultural resources, while simultaneously contributing to long-term economic growth. In poorer nations, increased energy efficiency in agricultural value-added production, in particular, can provide large mitigation benefits. Under certain scenarios, the efficiency of agricultural systems can stagnate and could exert pressure on grasslands and rangelands, thereby impacting on land degradation and desertification. Rebound effects can also occur, with adverse impacts on emissions.

Al-Mansour F and Jejcic V 2017; Baptista et al. 2013; Begum et al. 2015; Gunatilake et al. 2014; Jebli and Youssef 2017; Van Vuuren

et al. 2017b

Integrated response option

Description

Context and caveats

Supporting evidence

Management of urban sprawl

Unplanned urbanisation leading to sprawl and extensification of cities along the rural-urban fringe has been identified as a driver of forest and agricultural land loss and a threat to food production around cities. It
has been estimated that urban expansion will result in
a 1.8–2.4% loss of global croplands by 2030. This rapid urban expansion is especially strong in new emerging towns and cities in Asia and Africa. Policies to prevent such urbanisation have included integrated land-use planning, agricultural zoning ordinances and agricultural districts, urban redevelopment, arable land reclamation, and transfer/purchase of development rights or easements.

The prevention of uncontrolled urban sprawl may provide adaptation co-benefits, but adverse side effects for adaptation might arise due to restricted ability of people to move in response to climate change.

Barbero-Sierra et al. 2013; Bren d’Amour et al. 2016; Cai et al. 2013; Chen 2007; Francis et al. 2012; Gibson et al. 2015; Lee et al. 2015; Qian et al. 2015; Shen et al. 2017; Tan et al. 2009

Livelihood diversification

When households’ livelihoods depend on a small number of sources of income without much diversification, and when those income sources are in fields that are highly climate dependent, like agriculture and fishing, this dependence can put food security and livelihoods at risk. Livelihood diversification (drawing from a portfolio of dissimilar sources of livelihood as a tool to spread risk) has been identified as one option to increase incomes and reduce poverty, increase food security, and promote climate resilience and risk reduction.

Livelihood diversification offers benefits for desertification and land degradation, particularly through non-traditional crops or trees in agroforestry systems which improve soil. Livelihood diversification may increase on-farm biodiversity due to these investments in more ecosystem-mimicking production systems, like agroforestry and polycultures. Diversification into non-agricultural fields, such as wage labour or trading, is increasingly favoured by farmers as

a low-cost strategy, particularly to respond to increasing climate risks.

Adger 1999; Ahmed and Stepp 2016; Antwi-Agyei et al. 2014; Barrett et al. 2001; Berman
et al. 2012; Bryceson 1999; DiGiano and Racelis 2012; Ellis 1998, 2008; Little et al. 2001; Ngigi et al. 2017; Rakodi 1999; Thornton and Herrero 2014

Use of local seeds

Using local seeds (also called seed sovereignty) refers
to use of non-improved, non-commercial seeds varieties. These can be used and stored by local farmers as low-cost inputs and can often help contribute to the conservation of local varieties and landraces, increasing local biodiversity. Many local seeds also require no pesticide or fertiliser use, leading to less land degradation in their use.

Use of local seeds is important in the many parts of
the developing world that do not rely on commercial
seed inputs. Promotion of local seed-saving initiatives
can include seed networks, banks and exchanges, and non-commercial open source plant breeding. These locally developed seeds can help protect local agrobiodiversity and can often be more climate resilient than generic commercial varieties, although the impacts on food security and overall land degradation are inconclusive.

Bowman 2015; Campbell and Veteto 2015; Coomes et al. 2015; Kloppenberg 2010; Luby et al. 2015; Van Niekerk and Wynberg 2017; Patnaik et al. 2017; Reisman 2017; Vasconcelos et al. 2013; Wattnem 2016

Integrated response option

Description

Context and caveats

Supporting evidence

Disaster risk management

Disaster risk management encompasses many
approaches to try to reduce the consequences of climate- and weather-related disasters and events
on socio-economic systems. The Hyogo Framework for Action is a UN framework for nations to build resilience to disasters through effective integration of disaster risk considerations into sustainable development policies. For example, in Vietnam a national strategy on disasters based on Hyogo has introduced the concept of a ‘four- on-the-spot’ approach for disaster risk management of: proactive prevention, timely response, quick and effective recovery, and sustainable development. Other widespread approaches to disaster risk management include using early warning systems that can encompass 1) education systems, 2) hazard and risk maps, 3) hydrological and meteorological monitoring (such as flood forecasting

or extreme weather warnings), and 4) communications systems to pass on information to enable action. These approaches have long been considered to reduce the risk of household asset damage during one-off climate events and are increasingly being combined with climate adaptation policies.

Community-based disaster risk management has been pointed to as one of the most successful ways to ensure that information reaches the people who need to be participants in risk reduction. Effective disaster risk management approaches must be ‘end-to-end,’ reaching communities at risk and supporting and empowering vulnerable communities to take appropriate action. The most effective early warning systems are not simply technical systems of information dissemination, but utilise and develop community capacities, create local ownership of the system, and are based on
a shared understanding of needs and purpose. Tapping into existing traditional or local knowledge has also been recommended for disaster risk management approaches
to reducing vulnerability.

Ajibade and McBean 2014; Alessa et al. 2016; Bouwer et al. 2014; Carreño et al. 2007; Cools et al. 2016; Djalante et al. 2012; Garschagen 2016; Maskrey 2011; Mercer 2010; Schipper and Pelling 2006; Sternberg and Batbuyan 2013; Thomalla et al. 2006; Vogel and O’Brien 2006

Risk-sharing instruments

Risk-sharing instruments can encompass a variety of approaches. Intra-household risk pooling is a common strategy in rural communities, such as through extended family financial transfers; one study found that 65% of poor households in Jamaica report receiving transfers, and such transfers can account for up to 75% of household income or more after crisis events. Community rotating savings and credit associations (ROSCAs) have long been used for general risk pooling and can be a source of financing to cope with climate variability as well. Credit services have been shown to be important for adaptation actions and risk reduction. Insurance of various kinds is also a form of risk pooling. Commercial crop insurance is one of the most widely used risk-hedging financial vehicles, and can involve both traditional indemnity-based insurance that reimburses clients for estimated financial losses from shortfalls, or index insurance that pays out the value of

an index (such as weather events) rather than actual losses; the former is more common for large farms in the developed world and the latter for smaller non-commercial farms in developing countries.

Locally developed risk-pooling measures show general positive impacts on household livelihoods. However, more commercial approaches have mixed effects. Commercial crop insurance is highly subsidised in much of the developed world. Index insurance programmes have often failed

to attract sufficient buyers or have remained financially unfeasible for commercial insurance sellers. The overall impact of index insurance on food production supply and access has also not been assessed. Traditional crop insurance has generally been seen as positive for food security as it leads to expansion of agricultural production areas and increased food supply. However, insurance may also ‘mask’ truly risky agriculture and prevent farmers from seeking less risky production strategies. Insurance can also provide perverse incentives for farmers to bring additional lands into crop production, leading to greater risk of degradation.

Akter et al. 2016; Annan and Schlenker 2015; Claassen et al. 2011a; Fenton et al. 2017; Giné
et al. 2008; Goodwin and Smith 2003; Hammill et al. 2008; Havemenn and Muccione 2011; Jaworski 2016; Meze-Hausken
et al. 2009; Morduch and Sharma 2002; Bhattamishra and Barrett 2010; Peterson 2012; Sanderson
et al. 2013; Skees and Collier 2012; Smith and Glauber 2012