Editing IPCC:AR6/SRCCL/Chapter-6 (section)

== 6.3 Potentials for addressing the land challenges ==

<div id="article-6-3-potentials-for-addressing-the-land-challenges-block-1"></div>

In this section, we assess how each of the integrated response options described in Section 6.2 address the land challenges of climate change mitigation (Section 6.3.1), climate change adaptation (Section 6.3.2), desertification (Section 6.3.3), land degradation (Section 6.3.4), and food security (Section 6.3.5). The quantified potentials across all of mitigation, adaptation, desertification, land degradation and food security are summarised and categorised for comparison in Section 6.3.6.

<span id="potential-of-the-integrated-response-options-for-delivering-mitigation"></span>
=== 6.3.1 Potential of the integrated response options for delivering mitigation ===

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In this section, the impacts of integrated response options on climate change mitigation are assessed.

<div id="section-6-3-1-1-integrated-response-options-based-on-land-management"></div>

<span id="integrated-response-options-based-on-land-management-1"></span>
==== 6.3.1.1 Integrated response options based on land management ====

<div id="section-6-3-1-1-integrated-response-options-based-on-land-management-block-1"></div>

In this section, the impacts on climate change mitigation of integrated response options based on land management are assessed. Some of the caveats of these potential mitigation studies are discussed in Chapter 2 and Section 6.2.1.

''Integrated response options based on land management in agriculture''

Increasing the productivity of land used for food production can deliver significant mitigation by avoiding emissions that would occur if increased food demand were met through expansion of the agricultural land area (Burney et al. 2010 <sup>[[#fn:r238|238]]</sup> ). If pursued through increased agrochemical inputs, numerous adverse impacts on GHG emissions (and other environmental sustainability) can occur (Table 6.5), but, if pursued through sustainable intensification, increased food productivity could provide high levels of mitigation. For example, yield improvement has been estimated to have contributed to emissions savings of &gt;13 GtCO <sub>2</sub> e yr <sup>–1</sup>  since 1961 (Burney et al. 2010 <sup>[[#fn:r239|239]]</sup> ) (Table 6.13). This can also reduce the GHG intensity of products (Bennetzen et al. 2016a,b) which means a smaller environmental footprint of production, since demand can be met using less land and/or with fewer animals.

Improved cropland management could provide moderate levels of mitigation (1.4–2.3 GtCO <sub>2</sub> e yr <sup>–1</sup> ) (Smith et al. 2008, 2014; Pradhan et al. 2013 <sup>[[#fn:r240|240]]</sup> ) (Table 6.13). The lower estimate of potential is from Pradhan et al. (2013) for decreasing emissions intensity, and the upper end of technical potential is estimated by adding technical potentials for cropland management (about 1.4 GtCO <sub>2</sub> e yr <sup>–1</sup> ), rice management (about 0.2 GtCO <sub>2</sub> e yr <sup>–1</sup> ) and restoration of degraded land (about 0.7 GtCO <sub>2</sub> e yr <sup>–1</sup> ) from Smith et al. (2008) <sup>[[#fn:r241|241]]</sup> and Smith et al. (2014). Note that much of this potential arises from soil carbon sequestration so there is an overlap with that response option. (Section 6.3.1.1).

Grazing lands can store large stocks of carbon in soil and root biomass compartments (Conant and Paustian 2002 <sup>[[#fn:r243|243]]</sup> ; O’Mara 2012 <sup>[[#fn:r244|244]]</sup> ; Zhou et al. 2017 <sup>[[#fn:r245|245]]</sup> ). The global mitigation potential is moderate (1.4–1.8 GtCO <sub>2</sub> e yr <sup>–1</sup> ), with the lower value in the range for technical potential taken from Smith et al. (2008) <sup>[[#fn:r246|246]]</sup> which includes only grassland management measures, and the upper value in the range from Herrero et al. (2016) <sup>[[#fn:r247|247]]</sup> , which includes also indirect effects and some components of livestock management, and soil carbon sequestration, so there is overlap with these response options (Section 6.3.1.1). Conant et al. (2005) <sup>[[#fn:r248|248]]</sup> caution that increases in soil carbon stocks could be offset by increases in N <sub>2</sub> O fluxes.

The mitigation potential of improved livestock management is also moderate (0.2–1.8 GtCO <sub>2</sub> e yr <sup>–1</sup> ; Smith et al. (2008) including only direct livestock measures; Herrero et al. (2016) <sup>[[#fn:r249|249]]</sup> include also indirect effects, and some components of grazing land management and soil carbon sequestration) to high (6.13 GtCO <sub>2</sub> e yr <sup>–1</sup> ) (Pradhan et al. 2013 <sup>[[#fn:r250|250]]</sup> ) (Table 6.13). There is an overlap with other response options (Section 6.3.1.1).

Zomer et al. (2016) <sup>[[#fn:r251|251]]</sup> reported that the trees agroforestry landscapes have increased carbon stock by 7.33 GtCO <sub>2</sub>  between 2000–2010, which is equivalent to 0.7 GtCO <sub>2</sub> e yr <sup>–1</sup> . Estimates of global potential range from 0.1 GtCO <sub>2</sub> e yr <sup>–1</sup> to 5.7 GtCO <sub>2</sub> e yr <sup>–1</sup> (from an optimum implantation scenario of Hawken (2017) <sup>[[#fn:r252|252]]</sup> , based on an assessment of all values in Griscom et al. (2017), Hawken (2017) <sup>[[#fn:r253|253]]</sup> , Zomer et al. (2016) and Dickie et al. (2014) <sup>[[#fn:r254|254]]</sup> (Table 6.13).

Agricultural diversification mainly aims at increasing climate resilience, but it may have a small (but globally unquantified) mitigation potential as a function of type of crop, fertiliser management, tillage system, and soil type (Campbell et al. 2014 <sup>[[#fn:r255|255]]</sup> ; Cohn et al. 2017 <sup>[[#fn:r256|256]]</sup> ).

Reducing conversion of grassland to cropland could provide significant climate mitigation by retaining soil carbon stocks that might otherwise be lost. When grasslands are converted to croplands, they lose about 36% of their soil organic carbon stocks after 20 years (Poeplau et al. 2011 <sup>[[#fn:r257|257]]</sup> ). Assuming an average starting soil organic carbon stock of grasslands of 115 tC ha <sup>–1</sup> (Poeplau et al. 2011 <sup>[[#fn:r258|258]]</sup> ), this is equivalent to a loss of 41.5 tC ha <sup>–1</sup> on conversion to cropland. Mean annual global cropland conversion rates (1961–2003) have been around 47,000 km2 yr <sup>–1</sup> (Krause et al. 2017 <sup>[[#fn:r259|259]]</sup> ), or 940000 km2 over a 20-year period. The equivalent loss of soil organic carbon over 20 years would therefore be 14 GtCO <sub>2</sub> e = 0.7 GtCO <sub>2</sub> e yr <sup>–1</sup> . Griscom et al. (2017) <sup>[[#fn:r260|260]]</sup> estimate a cost-effective mitigation potential of 0.03 GtCO <sub>2</sub> e yr <sup>–1</sup> (Table 6.13).

Integrated water management provides moderate benefits for climate mitigation due to interactions with other land management strategies. For example, promoting soil carbon conservation (e.g., reduced tillage) can improve the water retention capacity of soils. Jat et al. (2015) <sup>[[#fn:r261|261]]</sup> found that improved tillage practices and residue incorporation increased water-use efficiency by 30%, rice–wheat yields by 5–37%, income by 28–40% and reduced GHG emission by 16–25%. While irrigated agriculture accounts for only 20% of the total cultivated land, the energy consumption from groundwater irrigation is significant. However, current estimates of mitigation potential are limited to reductions in GHG emissions mainly in cropland and rice cultivation (Smith et al. 2008 <sup>[[#fn:r262|262]]</sup> , 2014) (Chapter 2 and Table 6.13). Li et al. (2006) <sup>[[#fn:r263|263]]</sup> estimated a 0.52–0.72 GtCO <sub>2</sub> e yr <sup>–1</sup> reduction using the alternate wetting and drying technique. Current estimates of N <sub>2</sub> O release from terrestrial soils and wetlands accounts for 10–15% of anthropogenically fixed nitrogen on the Earth System (Wang et al. 2017 <sup>[[#fn:r264|264]]</sup> ).

Table 6.13 summarises the mitigation potentials for agricultural response options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.4.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-1-1-integrated-response-options-based-on-land-management-block-2"></div>

<span id="table-6.13"></span>
<!-- START TABLE -->
'''Table 6.13'''

<span id="mitigation-effects-of-response-options-based-on-land-management-in-agriculture."></span>
'''Mitigation effects of response options based on land management in agriculture.'''

<!-- TABLE -->
{| class="wikitable"
|-
! Integrated response option
! Potential
! Confidence
! Citation
|-
| Increased food productivity
| &gt;13 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Low confidence
| Chapter 5<br />
Burney et al. 2010
|-
| Improved cropland managementa
| 1.4–2.3 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Medium confidence
| Chapter 2; Chapter 5<br />
Pradhan et al. 2013; Smith et al. 2008, 2014
|-
| Improved grazing land managementa
| 1.4–1.8 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Medium confidence
| Chapter 2; Chapter 5<br />
Conant et al. 2017; Herrero et al. 2016; Smith et al. 2008, 2014
|-
| Improved livestock managementa
| 0.2–2.4 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Medium confidence
| Chapter 2; Chapter 5<br />
Herrero et al. 2016; Smith et al. 2008, 2014
|-
| Agroforestry
| 0.1–5.7 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Medium confidence
| Chapter 2<br />
Albrecht and Kandji 2003; Dickie et al. 2014; Griscom et al. 2017; Hawken 2017; Zomer et al. 2016
|-
| Agricultural diversification
| &gt;0
| Low confidence
| Campbell et al. 2014; Cohn et al. 2017
|-
| Reduced grassland conversion to cropland
| 0.03–0.7 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Low confidence
| Note high value not shown in Chapter 2; calculated from values in Griscom et al. 2017; Krause et al. 2017; Poeplau et al. 2011
|-
| Integrated water management
| 0.1–0.72 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Low confidence
| IPCC 2014; Howell et al. 2015; Li et al. 2006; Rahman and Bulbul 2015; Smith et al. 2008, 2014
|}
<!-- END TABLE -->

a Note that Chapter 2 reports mitigation potential for subcategories within this response option and not the combined total reported here.

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''Integrated response options based on land management in forests''

Forest management could potentially contribute to moderate mitigation benefits globally, up to about 2 GtCO <sub>2</sub> e yr <sup>–1</sup> (Chapter 2, Table 6.14). For managed forests, the most effective forest carbon mitigation strategy is the one that, through increasing biomass productivity, optimises the carbon stocks (in forests and in long- lived products) as well as the wood substitution effects for a given time frame (Smyth et al. 2014 <sup>[[#fn:r265|265]]</sup> ; Grassi et al. 2018 <sup>[[#fn:r266|266]]</sup> ; Nabuurs et al. 2007 <sup>[[#fn:r267|267]]</sup> ; Lewis et al. 2019 <sup>[[#fn:r268|268]]</sup> ; Kurz et al. 2016 <sup>[[#fn:r269|269]]</sup> ; Erb et al. 2017 <sup>[[#fn:r279|279]]</sup> ). Estimates of the mitigation potential vary also depending on the counterfactual, such as business-as-usual management (e.g., Grassi et al. 2018) or other scenarios. Climate change will affect the mitigation potential of forest management due to an increase in extreme events like fires, insects and pathogens (Seidl et al. 2017 <sup>[[#fn:r271|271]]</sup> ). More detailed estimates are available at regional or biome level. For instance, according to Nabuurs et al. (2017), the implementation of Climate- Smart Forestry (a combination of forest management, expansion of forest areas, energy substitution, establishment of forest reserves, etc.) in the European Union has the potential to contribute to an additional 0.4 GtCO <sub>2</sub> e yr <sup>–1</sup> mitigation by 2050. Sustainable forest management is often associated with a number of co-benefits for adaptation, ecosystem services, biodiversity conservation, microclimatic regulation, soil erosion protection, coastal area protection and water and flood regulation (Locatelli 2011 <sup>[[#fn:r272|272]]</sup> ). Forest management mitigation measures are more likely to be long- lasting if integrated into adaptation measures for communities and ecosystems, for example, through landscape management (Locatelli et al. 2011 <sup>[[#fn:r273|273]]</sup> ). Adoption of reduced-impact logging and wood processing technologies along with financial incentives can reduce forest fires, forest degradation, maintain timber production, and retain carbon stocks (Sasaki et al. 2016 <sup>[[#fn:r274|274]]</sup> ). Forest certification may support sustainable forest management, helping to prevent forest degradation and over-logging (Rametsteiner and Simula 2003 <sup>[[#fn:r275|275]]</sup> ). Community forest management has proven a viable model for sustainable forestry, including for carbon sequestration (Chhatre and Agrawal 2009 <sup>[[#fn:r276|276]]</sup> ) (Chapter 7, Section 7.7.4).

Reducing deforestation and forest degradation rates represents one of the most effective and robust options for climate change mitigation, with large mitigation benefits globally (Chapters 2 and 4, and Table 6.14). Because of the combined climate impacts of GHGs and biophysical effects, reducing deforestation in the tropics has a major climate mitigation effect, with benefits at local levels too (Alkama and Cescatti 2016 <sup>[[#fn:r277|277]]</sup> ) (Chapter 2). Reduced deforestation and forest degradation typically lead to large co-benefits for other ecosystem services (Table 6.14).

A large range of estimates exist in the scientific literature for the mitigation potential of reforestation and forest restoration, and they sometimes overlap with estimates for afforestation. At global level, the overall potential for these options is large, reaching about 10 GtCO <sub>2</sub> e yr <sup>–1</sup> (Chapter 2 and Table 6.14). The greatest potential for these options is in tropical and subtropical climate (Houghton and Nassikas 2018 <sup>[[#fn:r278|278]]</sup> ). Furthermore, climate change mitigation benefits of afforestation, reforestation and forest restoration are reduced at high latitudes owing to the surface albedo feedback (Chapter 2).

Table 6.14 summarises the mitigation potentials for forest response options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-1-1-integrated-response-options-based-on-land-management-block-4"></div>

<span id="table-6.14"></span>
<!-- START TABLE -->
'''Table 6.14'''

<span id="mitigation-effects-of-response-options-based-on-land-management-in-forests."></span>
'''Mitigation effects of response options based on land management in forests.'''

<!-- TABLE -->
{| class="wikitable"
|-
! Integrated response option
! Potential
! Confidence
! Citation
|-
| Forest management
| 0.4–2.1 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Medium confidence
| Chapter 2<br />
Griscom et al. 2017; Sasaki et al. 2016
|-
| Reduced deforestation and forest degradation
| 0.4–5.8 GtCO <sub>2</sub> e yr <sup>–1</sup>
| High confidence
| Chapter 2<br />
Baccini et al. 2017; Griscom et al. 2017; Hawken 2017; Houghton et al. 2015; Houghton and Nassikas 2018; Smith et al. 2014
|-
| Reforestation and forest restoration
| 1.5–10.1 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Medium confidence
| Chapter 2<br />
Dooley and Kartha 2018; Griscom et al. 2017; Hawken 2017; Houghton and Nassikas 2017<br />
Estimates partially overlapping with Afforestation
|-
| Afforestation
| 0.5–8.9 GtCO <sub>2</sub> e yr <sup>–1</sup>
| Medium confidence
| Chapter 2<br />
Fuss et al. 2018; Hawken 2017; Kreidenweis et al. 2016; Lenton 2010. Estimates partially overlapping with Reforestation
|}
<!-- END TABLE -->

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''Integrated response options based on land management of soils''

The global mitigation potential for increasing soil organic matter stocks in mineral soils is estimated to be in the range of 1.3–5.1 GtCO <sub>2</sub> e yr <sup>–1</sup> , though the full literature range is wider (Fuss et al. 2018 <sup>[[#fn:r1247|1247]]</sup> ; Lal 2004 <sup>[[#fn:r280|280]]</sup> ; de Coninck et al. 2018; Sanderman et al. 2017 <sup>[[#fn:r281|281]]</sup> ; Smith et al. 2008 <sup>[[#fn:r282|282]]</sup> ; Smith 2016 <sup>[[#fn:r283|283]]</sup> ) (Table 6.15).

The management and control of erosion may prevent losses of organic carbon in water- or wind- transported sediments, but since the final fate of eroded material is still debated, ranging from a source of 1.36–3.67 GtCO <sub>2</sub> e yr <sup>–1</sup> (Jacinthe and Lal 2001 <sup>[[#fn:r1268|1268]]</sup> ; Lal 2004 <sup>[[#fn:r284|284]]</sup> ) to a sink of 0.44–3.67 GtCO <sub>2</sub> e yr <sup>–1</sup> (Smith et al. 2001 <sup>[[#fn:r286|286]]</sup> ; Stallard 1998 <sup>[[#fn:r287|287]]</sup> ; Van Oost et al. 2007 <sup>[[#fn:r288|288]]</sup> ) (Table 6.15), the overall impact of erosion control on mitigation is context-specific and uncertain at the global level (Hoffmann et al. 2013 <sup>[[#fn:r289|289]]</sup> ).

Salt-affected soils are highly constrained environments that require permanent prevention of salinisation. Their mitigation potential is likely to be small (Wong et al. 2010 <sup>[[#fn:r290|290]]</sup> ; UNCTAD 2011 <sup>[[#fn:r291|291]]</sup> ; Dagar et al. 2016 <sup>[[#fn:r292|292]]</sup> ).

Soil compaction prevention could reduce N2O emissions by minimising anoxic conditions favourable for denitrification (Mbow et al. 2010), but its carbon sequestration potential depends on crop management, and the global mitigation potential, though globally unquantified, is likely to be small (Chamen et al. 2015 <sup>[[#fn:r293|293]]</sup> ; Epron et al. 2016 <sup>[[#fn:r294|294]]</sup> ; Tullberg et al. 2018 <sup>[[#fn:r295|295]]</sup> ) (Table 6.15).

For biochar, a global analysis of technical potential, in which biomass supply constraints were applied to protect against food insecurity, loss of habitat and land degradation, estimated technical potential abatement of 3.7–6.6 GtCO <sub>2</sub> e yr <sup>–1</sup> (including 2.6–4.6 GtCO <sub>2</sub> e yr <sup>–1</sup> carbon stabilisation). Considering all published estimates by Woolf et al. (2010) <sup>[[#fn:r296|296]]</sup> , Smith (2016) <sup>[[#fn:r297|297]]</sup> , Fuss et al. (2018) <sup>[[#fn:r298|298]]</sup> , Griscom et al. (2017) <sup>[[#fn:r299|299]]</sup> , Hawken (2017) <sup>[[#fn:r300|300]]</sup> , Paustian et al. (2016) <sup>[[#fn:r301|301]]</sup> , Powell and Lenton (2012) <sup>[[#fn:r302|302]]</sup> .

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<span id="table-6.15"></span>
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'''Table 6.15'''

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'''Mitigation effects of response options based on land management of soils.'''
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[[File:7cabfbe1e3cd7577f43b8c875a5666d1 table-6.15.png]]

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Dickie et al. (2014) <sup>[[#fn:r303|303]]</sup> , Lenton (2010) <sup>[[#fn:r1248|1248]]</sup> , Lenton (2014) <sup>[[#fn:r1249|1249]]</sup> , Roberts et al. (2009) <sup>[[#fn:r1250|1250]]</sup> , Pratt and Moran (2010) <sup>[[#fn:r1251|1251]]</sup> and IPCC (2018) <sup>[[#fn:r1269|1269]]</sup> , the low value for the range of potentials of 0.03 GtCO <sub>2</sub> e yr <sup>–1</sup> is for the ‘plausible’ scenario of Hawken, (2017) <sup>[[#fn:r304|304]]</sup> (Table 6.15). Fuss et al. (2018) <sup>[[#fn:r1254|1254]]</sup> propose a range of 0.5–2 GtCO2e yr–1 as the sustainable potential for negative emissions through biochar, similar to the range proposed by Smith (2016) <sup>[[#fn:r305|305]]</sup> and IPCC (2018) <sup>[[#fn:r1252|1252]]</sup> .

Table 6.15 summarises the mitigation potentials for soil-based response options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

''Integrated response options based on land management in all/other ecosystems''

For fire management, total emissions from fires have been in the order of 8.1 GtCO <sub>2</sub> e yr <sup>–1</sup> 1 for the period 1997–2016 (Chapter 2 and Cross-Chapter Box 3) and there are important synergies between air pollution and climate change control policies. Reduction in fire CO2 emissions due to fire suppression and landscape fragmentation associated with increases in population density is calculated to enhance land carbon uptake by 0.48 GtCO <sub>2</sub> e yr <sup>–1</sup> for the 1960–2009 period (Arora and Melton 2018 <sup>[[#fn:r306|306]]</sup> ) (Table 6.16).

Management of landslides and natural hazards is a key climate adaptation option but, due to limited global areas vulnerable to landslides and natural hazards, its mitigation potential is likely to be modest (Noble et al. 2014 <sup>[[#fn:r307|307]]</sup> ).

In terms of management of pollution, including acidification, United Nations Environment Programme (UNEP) and World Meterological Organization (WMO) (2011) <sup>[[#fn:r1253|1253]]</sup> and Shindell et al. (2012) <sup>[[#fn:r308|308]]</sup> identified measures targeting reduction in short-lived climate pollutant (SLCP) emissions that reduce projected global mean warming about 0.5°C by 2050. Bala et al. (2013) <sup>[[#fn:r309|309]]</sup> reported that a recent coupled modelling study showed nitrogen deposition and elevated CO2 could have a synergistic effect, which could explain 47% of terrestrial carbon uptake in the 1990s. Estimates of global terrestrial carbon uptake due to current nitrogen deposition ranges between 0.55 and 1.28 GtCO2 yr–1 (De Vries et al. 2006, 2009 <sup>[[#fn:r1254|1254]]</sup> ; Bala et al. 2013 <sup>[[#fn:r1255|1255]]</sup> ; Zaehle and Dalmonech 2011 <sup>[[#fn:r310|310]]</sup> ) (Table 6.16).

There are no global data on the impacts of management of invasive species/encroachment on mitigation.

Coastal wetland restoration could provide high levels of climate mitigation, with avoided coastal wetland impacts and coastal wetland restoration estimated to deliver 0.3–3.1 GtCO <sub>2</sub> e yr <sup>–1</sup> in total when considering all global estimates from Griscom et al. (2017) <sup>[[#fn:r311|311]]</sup> , Hawken (2017) <sup>[[#fn:r1255|1255]]</sup> , Pendleton et al. (2012) <sup>[[#fn:r313|313]]</sup> , Howard et al. (2017) <sup>[[#fn:r314|314]]</sup> and Donato et al. (2011) <sup>[[#fn:r315|315]]</sup> (Table 6.16).

Peatland restoration could provide moderate levels of climate mitigation, with avoided peat impacts and peat restoration estimated to deliver 0.6–2 GtCO <sub>2</sub> e yr <sup>–1</sup> from all global estimates published in Griscom et al. (2017) <sup>[[#fn:r316|316]]</sup> , Hawken (2017) <sup>[[#fn:r1256|1256]]</sup> , Hooijer et al. (2010) <sup>[[#fn:r319|319]]</sup> , Couwenberg et al. (2010) <sup>[[#fn:r1257|1257]]</sup> and Joosten and Couwenberg (2008) <sup>[[#fn:r320|320]]</sup> , though there could be an increase in methane emissions after restoration (Jauhiainen et al. 2008 <sup>[[#fn:r321|321]]</sup> ) (Table 6.16).

Mitigation potential from biodiversity conservation varies depending on the type of intervention and specific context. Protected areas are estimated to store over 300 Gt carbon, roughly corresponding to 15% of terrestrial carbon stocks (Campbell et al. 2008 <sup>[[#fn:r322|322]]</sup> ; Kapos et al. 2008 <sup>[[#fn:r323|323]]</sup> ). At global level, the potential mitigation resulting from protection of these areas for the period 2005–2095 is, on average, about 0.9 GtCO <sub>2</sub> e yr <sup>–1</sup> relative to a reference scenario (Calvin et al. 2014 <sup>[[#fn:r324|324]]</sup> ). The potential effects on the carbon cycle of management of wild animal species are context dependent. For example, moose browsing in boreal forests can decrease the carbon uptake of ecosystems by up to 75% (Schmitz et al. 2018 <sup>[[#fn:r325|325]]</sup> ), and reducing moose density through active population management in Canada is estimated to be a carbon sink equivalent to about 0.37 GtCO <sub>2</sub> e yr <sup>–1</sup> (Schmitz et al. 2014 <sup>[[#fn:r326|326]]</sup> ).

Table 6.16 summarises the mitigation potentials for land management response options in all/other ecosystems, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-1-1-integrated-response-options-based-on-land-management-block-8"></div>

<span id="table-6.16"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.16'''

<span id="mitigation-effects-of-response-options-based-on-land-management-in-allother-ecosystems."></span>
<!-- IMG CAPTION -->
'''Mitigation effects of response options based on land management in all/other ecosystems.'''
<!-- IMG FILE -->
[[File:b3e5c39fc7a980bbdf74aa935f27dd47 table-6.16.png]]

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<div id="section-6-3-1-1-integrated-response-options-based-on-land-management-block-9"></div>

''Integrated response options based on land management specifically for carbon dioxide removal (CDR)''

Enhanced mineral weathering provides substantial climate mitigation, with a global mitigation potential in the region of about 0.5–4 GtCO <sub>2</sub> e yr <sup>–1</sup> (Beerling et al. 2018 <sup>[[#fn:r327|327]]</sup> ; Lenton 2010 <sup>[[#fn:r328|328]]</sup> ; Smith et al. 2016a <sup>[[#fn:r329|329]]</sup> ; Taylor et al. 2016 <sup>[[#fn:r330|330]]</sup> ) (Table 6.17).

The mitigation potential for bioenergy and BECCS derived from bottom-up models is large (IPCC 2018 <sup>[[#fn:r331|331]]</sup> ) (Chapter 2 and Cross- Chapter Box 7 in this chapter), with technical potential estimated at 100–300 EJ yr <sup>–1</sup> (Chum et al. 2011 <sup>[[#fn:r332|332]]</sup> ; Cross-Chapter Box 7 in Chapter 6) or up to about 11 GtCO2 yr–1 (Chapter 2). These estimates, however, exclude N2O associated with fertiliser application and land- use change emissions. Those effects are included in the modelled scenarios using bioenergy and BECCS, with the sign and magnitude depending on where the bioenergy is grown (Wise et al. 2015 <sup>[[#fn:r333|333]]</sup> ), at what scale, and whether nitrogen fertiliser is used.

Table 6.17 summarises the mitigation potentials for land management options specifically for CDR, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-1-1-integrated-response-options-based-on-land-management-block-10"></div>

<span id="table-6.17"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.17'''

<span id="mitigation-effects-of-response-options-based-on-land-management-specifically-for-cdr."></span>
<!-- IMG CAPTION -->
'''Mitigation effects of response options based on land management specifically for CDR.'''
<!-- IMG FILE -->
[[File:e5cbabbf887d1af98db9d7a3144d1b5c table-6.17.png]]

<!-- END IMG -->
<div id="section-6-3-1-2-integrated-response-options-based-on-value-chain-management"></div>

<span id="integrated-response-options-based-on-value-chain-management-1"></span>
==== 6.3.1.2 Integrated response options based on value chain management ====

<div id="section-6-3-1-2-integrated-response-options-based-on-value-chain-management-block-1"></div>

In this section, the impacts on climate change mitigation of integrated response options based on value chain management are assessed.

''Integrated response options based on value chain management through demand management''

Dietary change and waste reduction can provide large benefits for mitigation, with potentials of 0.7–8 GtCO2 yr–1 for both (Aleksandrowicz et al. 2016 <sup>[[#fn:r334|334]]</sup> ; Bajželj et al. 2014b <sup>[[#fn:r335|335]]</sup> ; Dickie et al. 2014 <sup>[[#fn:r336|336]]</sup> ; Hawken 2017 <sup>[[#fn:r337|337]]</sup> ; Hedenus et al. 2014 <sup>[[#fn:r338|338]]</sup> ; Herrero et al. 2016 <sup>[[#fn:r339|339]]</sup> ; Popp et al. 2010 <sup>[[#fn:r340|340]]</sup> ; Smith et al. 2013 <sup>[[#fn:r341|341]]</sup> ; Springmann et al. 2016 <sup>[[#fn:r342|342]]</sup> ; Stehfest et al. 2009 <sup>[[#fn:r343|343]]</sup> ; Tilman and Clark 2014 <sup>[[#fn:r344|344]]</sup> ). Estimates for food waste reduction (Bajželj et al. 2014b <sup>[[#fn:r345|345]]</sup> ; Dickie et al. 2014 <sup>[[#fn:r346|346]]</sup> ; Hiç et al. 2016 <sup>[[#fn:r347|347]]</sup> ; Hawken 2017 <sup>[[#fn:r348|348]]</sup> ) include both consumer/retailed waste and post-harvest losses (Table 6.18). Some studies indicate that material substitution has the potential for significant mitigation, with one study estimating a 14–31% reduction in global CO2 emissions (Oliver et al. 2014 <sup>[[#fn:r349|349]]</sup> ); other studies suggest more modest potential (Gustavsson et al. 2006 <sup>[[#fn:r350|350]]</sup> ) (Table 6.18).

Table 6.18 summarises the mitigation potentials for demand management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-1-2-integrated-response-options-based-on-value-chain-management-block-2"></div>

<span id="table-6.18"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.18'''

<span id="mitigation-effects-of-response-options-based-on-demand-management."></span>
<!-- IMG CAPTION -->
'''Mitigation effects of response options based on demand management.'''
<!-- IMG FILE -->
[[File:78fa23337d42ef1d2e565315f55e7e81 table-6.18.png]]

<!-- END IMG -->
<div id="section-6-3-1-2-integrated-response-options-based-on-value-chain-management-block-3"></div>

''Integrated response options based on value chain management through supply management''

While sustainable sourcing presumably delivers a mitigation benefit, there are no global estimates of potential. Palm oil production alone is estimated to contribute 0.038 to 0.045 GtC yr-1, and Indonesian palm oil expansion contributed up to 9% of tropical land-use change carbon emissions in the 2000s (Carlson and Curran 2013 <sup>[[#fn:r351|351]]</sup> ), however, the mitigation benefit of sustainable sourcing of palm oil has not been quantified. There are no estimates of the mitigation potential for urban food systems.

Efficient use of energy and resources in food transport and distribution contribute to a reduction in GHG emissions, estimated to be 1% of global CO2 emissions (James and James 2010 <sup>[[#fn:r352|352]]</sup> ; Vermeulen et al. 2012b <sup>[[#fn:r353|353]]</sup> ). Given that global CO2 emissions in 2017 were 37 GtCO2, this equates to 0.37 GtCO2 yr–1 (covering food transport and distribution, improved efficiency of food processing and retailing, and improved energy efficiency) (Table 6.19).

Table 6.19 summarises the mitigation potentials for supply management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-1-2-integrated-response-options-based-on-value-chain-management-block-4"></div>

<span id="table-6.19"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.19'''

<span id="mitigation-effects-of-response-options-based-on-supply-management."></span>
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'''Mitigation effects of response options based on supply management.'''
<!-- IMG FILE -->
[[File:40ab5df7ca9f89b471aae9e245c3ca92 table-6.19.png]]

<!-- END IMG -->
<div id="section-6-3-1-3-integrated-response-options-based-on-risk-management"></div>

<span id="integrated-response-options-based-on-risk-management-1"></span>
==== 6.3.1.3 Integrated response options based on risk management ====

<div id="section-6-3-1-3-integrated-response-options-based-on-risk-management-block-1"></div>

In this section, the impacts on climate change mitigation of integrated response options based on risk management are assessed. In general, because these options are focused on adaptation and other benefits, the mitigation benefits are modest, and mostly unquantified.

Extensive and less dense urban development tends to have higher energy usage, particularly from transport (Liu et al. 2015 <sup>[[#fn:r354|354]]</sup> ), such that a 10% reduction of very low-density urban fabrics is correlated with 9% fewer emissions per capita in Europe (Baur et al. 2015 <sup>[[#fn:r355|355]]</sup> ). However, the exact contribution to mitigation from the prevention of land conversion in particular has not been well quantified (Thornbush et al. 2013 <sup>[[#fn:r356|356]]</sup> ). Suggestions from select studies in the USA are that biomass decreases by half in cases of conversion from forest to urban land uses (Briber et al. 2015 <sup>[[#fn:r357|357]]</sup> ), and a study in Bangkok found a decline by half in carbon sinks in the urban area in the past 30 years (Ali et al. 2018 <sup>[[#fn:r358|358]]</sup> ).

There is no literature specifically on linkages between livelihood diversification and climate mitigation benefits, although some forms of diversification that include agroforestry would likely result in increased carbon sinks (Altieri et al. 2015 <sup>[[#fn:r359|359]]</sup> ; Descheemaeker et al. 2016 <sup>[[#fn:r360|360]]</sup> ). There is no literature exploring linkages between local seeds and GHG emission reductions, although use of local seeds likely reduces emissions associated with transport for commercial seeds, though the impact has not been quantified.

While disaster risk management can presumably have mitigation co- benefits, as it can help reduce food loss on-farm (e.g., crops destroyed before harvest or avoided animal deaths during droughts and floods meaning reduced production losses and wasted emissions), there is no quantified global estimate for this potential.

Risk-sharing instruments could have some mitigation co-benefits if they buffer household losses and reduce the need to expand agricultural lands after experiencing risks. However, the overall impacts of these are unknown. Further, commercial insurance may induce producers to bring additional land into crop production, particularly marginal or land with other risks that may be more environmentally sensitive (Claassen et al. 2011a). Policies to deny crop insurance to farmers who have converted grasslands in the USA resulted in a 9% drop in conversion, which likely has positive mitigation impacts (Claassen et al. 2011a <sup>[[#fn:r361|361]]</sup> ). Estimates of emissions from cropland conversion in the USA in 2016 were 23.8 MtCO2e, only some of which could be attributed to insurance as a driver.

Table 6.20 summarises the mitigation potentials for risk management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence is based.

<div id="section-6-3-1-3-integrated-response-options-based-on-risk-management-block-2"></div>

<span id="table-6.20"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.20'''

<span id="mitigation-effects-of-response-options-based-on-risk-management."></span>
<!-- IMG CAPTION -->
'''Mitigation effects of response options based on risk management.'''
<!-- IMG FILE -->
[[File:e906c9471e5bcf0cb5442ba0218b5ca4 table-6.20.png]]

<!-- END IMG -->
<span id="potential-of-the-integrated-response-options-for-delivering-adaptation"></span>
=== 6.3.2 Potential of the integrated response options for delivering adaptation ===

<div id="section-6-3-2-potential-of-the-integrated-response-options-for-delivering-adaptation-block-1"></div>

In this section, the impacts of integrated response options on climate change adaptation are assessed.

<div id="section-6-3-2-1-integrated-response-options-based-on-land-management"></div>

<span id="integrated-response-options-based-on-land-management-2"></span>
==== 6.3.2.1 Integrated response options based on land management ====

<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-1"></div>

In this section, the impacts on climate change adaptation of integrated response options based on land management are assessed.

Integrated response options based on land management in agriculture

Increasing food productivity by practices such as sustainable intensification improves farm incomes and allows households to build assets for use in times of stress, thereby improving resilience (Campbell et al. 2014 <sup>[[#fn:r362|362]]</sup> ). By reducing pressure on land and increasing food production, increased food productivity could be beneficial for adaptation (Campbell et al. 2014) (Chapter 2 and Section 6.3). Pretty et al. (2018) report that 163 million farms occupying 4.53 Mkm2 have passed a redesign threshold for application of sustainable intensification, suggesting the minimum number of people benefitting from increased productivity and adaptation benefits under sustainable intensification is &gt;163 million, with the total likely to be far higher (Table 6.21).

Improved cropland management is a key climate adaptation option, potentially affecting more than 25 million people, including a wide range of technological decisions by farmers. Actions towards adaptation fall into two broad overlapping areas: (i) accelerated adaptation to progressive climate change over decadal time scales, for example integrated packages of technology, agronomy and policy options for farmers and food systems, including changing planting dates and zones, tillage systems, crop types and varieties, and (ii) better management of agricultural risks associated with increasing climate variability and extreme events, for example, improved climate information services and safety nets (Vermeulen et al. 2012b <sup>[[#fn:r364|364]]</sup> ; Challinor et al. 2014 <sup>[[#fn:r365|365]]</sup> ; Lipper et al. 2014 <sup>[[#fn:r366|366]]</sup> ; Lobell 2014 <sup>[[#fn:r367|367]]</sup> ). In the same way, improved livestock management is another technological adaptation option potentially benefitting between 1 million and 25 million people. Crop and animal diversification are considered the most promising adaptation measures (Porter et al. 2014 <sup>[[#fn:r368|368]]</sup> ; Rojas-Downing et al. 2017 <sup>[[#fn:r369|369]]</sup> ). In grasslands and rangelands, regulation of stocking rates, grazing field dimensions, establishment of exclosures and locations of drinking fountains and feeders are strategic decisions by farmers to improve grazing management (Taboada et al. 2011 <sup>[[#fn:r370|370]]</sup> ; Mekuria and Aynekulu 2013 <sup>[[#fn:r371|371]]</sup> ; Porter et al. 2014 <sup>[[#fn:r372|372]]</sup> ).

Around 30% of the world’s rural population use trees across 46% of all agricultural landscapes (Lasco et al. 2014 <sup>[[#fn:r373|373]]</sup> ), meaning that up to 2.3 billion people benefit from agroforestry globally (Table 6.21).

Agricultural diversification is key to achieving climatic resilience (Campbell et al. 2014 <sup>[[#fn:r374|374]]</sup> ; Cohn et al. 2017 <sup>[[#fn:r375|375]]</sup> ). Crop diversification is one important adaptation option to progressive climate change (Vermeulen et al. 2012a <sup>[[#fn:r376|376]]</sup> ) and it can improve resilience by engendering a greater ability to suppress pest outbreaks and dampen pathogen transmission, as well as by buffering crop production from the effects of greater climate variability and extreme events (Lin 2011 <sup>[[#fn:r377|377]]</sup> ).

Reduced conversion of grassland to cropland may lead to adaptation benefits by stabilising soils in the face of extreme climatic events (Lal 2001 <sup>[[#fn:r378|378]]</sup> ), thereby increasing resilience, but since it would likely have a negative impact on food production/security (since croplands produce more food per unit area than grasslands), the wider adaptation impacts would likely be negative. However, there is no literature quantifying the global impact of avoidance of conversion of grassland to cropland on adaptation.

Integrated water management provides large co-benefits for adaptation (Dillon and Arshad 2016 <sup>[[#fn:r379|379]]</sup> ) by improving the resilience of food crop production systems to future climate change (Porter et al. 2014 <sup>[[#fn:r380|380]]</sup> ) (Chapter 2 and Table 6.7). Improving irrigation systems and integrated water resource management, such as enhancing urban and rural water supplies and reducing water evaporation losses (Dillon and Arshad 2016 <sup>[[#fn:r381|381]]</sup> ), are significant options for enhancing climate adaptation. Many technical innovations (e.g., precision water management) can lead to beneficial adaptation outcomes by increasing water availability and the reliability of agricultural production, using different techniques of water harvesting, storage, and its judicious utilisation through farm ponds, dams and community tanks in rainfed agriculture areas. Integrated water management response options that use freshwater would be expected to have few adverse side effects in regions where water is plentiful, but large adverse side effects in regions where water is scarce (Grey and Sadoff 2007 <sup>[[#fn:r382|382]]</sup> ; Liu et al. 2017 <sup>[[#fn:r383|383]]</sup> ; Scott et al. 2011 <sup>[[#fn:r384|384]]</sup> ).

Table 6.21 summarises the potentials for adaptation for agricultural response options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-2"></div>

<span id="table-6.21"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.21'''

<span id="adaptation-effects-of-response-options-based-on-land-management-in-agriculture."></span>
<!-- IMG CAPTION -->
'''Adaptation effects of response options based on land management in agriculture.'''
<!-- IMG FILE -->
[[File:ef1315e92f67f396502b9938c6abf506 table-6.21.png]]

<!-- END IMG -->
<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-3"></div>

''Integrated response options based on land management in forestry''

Forest management positively impacts on adaptation through limiting the negative effects associated with pollution (of air and fresh water), infections and other diseases, exposure to extreme weather events and natural disasters, and poverty (e.g., Smith et al. 2014). There is high agreement on the fact that reduced deforestation and forest degradation positively impact on adaptation and resilience of coupled human-natural systems. Based on the number of people affected by natural disasters (CRED 2015 <sup>[[#fn:r385|385]]</sup> ), the number of people depending to varying degrees on forests for their livelihoods (World Bank et al. 2009 <sup>[[#fn:r386|386]]</sup> ) and the current deforestation rate (Keenan et al. 2015 <sup>[[#fn:r387|387]]</sup> ), the estimated global potential effect for adaptation is largely positive for forest management, and moderately positive for reduced deforestation when cumulated until the end of the century (Table6.22).The uncertainty of these global estimates is high, for example, the impact of reduced deforestation may be higher when the large biophysical impacts on the water cycle (and thus drought) from deforestation (e.g., Alkama and Cescatti 2016 <sup>[[#fn:r388|388]]</sup> ) are taken into account (Chapter 2).

More robust qualitative, and some quantitative, estimates are available at local and regional level. According to Karjalainen et al. (2009) <sup>[[#fn:r389|389]]</sup> , reducing deforestation and habitat alteration contributes to limiting infectious diseases such as malaria in Africa, Asia and Latin America, thus lowering the expenses associated with healthcare treatments. Bhattacharjee and Behera (2017) <sup>[[#fn:r390|390]]</sup> found that human lives lost due to floods increase with reducing forest cover and increasing deforestation rates in India. In addition, maintaining forest cover in urban contexts reduces air pollution and therefore avoids mortality of about one person per year per city in US, and up to 7.6 people per year in New York City (Nowak et al. 2014 <sup>[[#fn:r391|391]]</sup> ). There is also evidence that reducing deforestation and forest degradation in mangrove plantations potentially improves soil stabilisation, and attenuates the impact of tropical cyclones and typhoons along the coastal areas in South and Southeast Asia (Chow 2018 <sup>[[#fn:r392|392]]</sup> ). At local scale, co-benefits between REDD+ and adaptation of local communities can potentially be substantial (Long 2013 <sup>[[#fn:r393|393]]</sup> ; Morita and Matsumoto 2018 <sup>[[#fn:r394|394]]</sup> ), even if often difficult to quantify, and not explicitly acknowledged (McElwee et al. 2017b <sup>[[#fn:r395|395]]</sup> ).

Forest restoration may facilitate the adaptation and resilience of forests to climate change by enhancing connectivity between forest areas and conserving biodiversity hotspots (Locatelli et al. 2011 <sup>[[#fn:r396|396]]</sup> , 2015b; Ellison et al. 2017 <sup>[[#fn:r397|397]]</sup> ; Dooley and Kartha 2018 <sup>[[#fn:r398|398]]</sup> ). Furthermore, forest restoration may improve ecosystem functionality and services, provide microclimatic regulation for people and crops, wood and fodder as safety nets, soil erosion protection and soil fertility enhancement for agricultural resilience, coastal area protection, water and flood regulation (Locatelli et al. 2015b <sup>[[#fn:r399|399]]</sup> ).

Afforestation and reforestation are important climate change adaptation response options (Reyer et al. 2009 <sup>[[#fn:r400|400]]</sup> ; Ellison et al. 2017 <sup>[[#fn:r401|401]]</sup> ; Locatelli et al. 2015b <sup>[[#fn:r402|402]]</sup> ), and can potentially help a large proportion of the global population to adapt to climate change and to associated natural disasters (Table 6.22). For example, trees generally mitigate summer mean warming and temperature extremes (Findell et al. 2017 <sup>[[#fn:r403|403]]</sup> ; Sonntag et al. 2016 <sup>[[#fn:r404|404]]</sup> ).

Table 6.22 summarises the potentials for adaptation for forest response options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-4"></div>

<span id="table-6.22"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.22'''

<span id="adaptation-effects-of-response-options-based-on-land-management-in-forests."></span>
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'''Adaptation effects of response options based on land management in forests.'''
<!-- IMG FILE -->
[[File:a201ec0115cbbead70a90afdf915374f table-6.22.png]]

<!-- END IMG -->
<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-5"></div>

''Integrated response options based on land management of soils''

Soil organic carbon increase is promoted as an action for climate change adaptation. Since increasing soil organic matter content is a measure to address land degradation (see Section 6.2.1), and restoring degraded land helps to improve resilience to climate change, soil carbon increase is an important option for climate change adaptation. With around 120,000 km2 lost to degradation every year, and over 3.2 billion people negatively impacted by land degradation globally (IPBES 2018 <sup>[[#fn:r1257|1257]]</sup> ), practices designed to increase soil organic carbon have a large potential to address adaptation challenges (Table 6.23).

Since soil erosion control prevents land degradation and desertification, it improves the resilience of agriculture to climate change and increases food production (Lal 1998 <sup>[[#fn:r406|406]]</sup> ; IPBES 2018 <sup>[[#fn:r407|407]]</sup> ), though the global number of people benefitting from improved resilience to climate change has not been reported in the literature. Using figures from (FAO and ITPS 2015), IPBES (2018) <sup>[[#fn:r407|407]]</sup> estimates that land losses due to erosion are equivalent to 1.5 Mkm2 of land used for crop production to 2050, or 45,000 km2 yr–1 (Foley et al. 2011). Control of soil erosion (water and wind) could benefit 11 Mkm2 of degraded land (Lal 2014 <sup>[[#fn:r408|408]]</sup> ), and improve the resilience of at least some of the 3.2 billion people affected by land degradation (IPBES 2018 <sup>[[#fn:r409|409]]</sup> ), suggesting positive impacts on adaptation. Management of erosion is an important climate change adaptation measure, since it reduces the vulnerability of soils to loss under climate extremes, thereby increasing resilience to climate change (Garbrecht et al. 2015 <sup>[[#fn:r410|410]]</sup> ).

Prevention and/or reversion of topsoil salinisation may require a combined management of groundwater, irrigation techniques, drainage, mulching and vegetation, with all of these considered relevant for adaptation (Qadir et al. 2013 <sup>[[#fn:r411|411]]</sup> ; UNCTAD 2011 <sup>[[#fn:r412|412]]</sup> ; Dagar et al. 2016 <sup>[[#fn:r413|413]]</sup> ). Taking into account the widespread diffusion of salinity problems, many people can benefit from its implementation by farmers. The relation between compaction prevention and/or reversion and climate adaption is less evident, and can be related to better hydrological soil functioning (Chamen et al. 2015 <sup>[[#fn:r414|414]]</sup> ; Epron et al. 2016 <sup>[[#fn:r415|415]]</sup> ; Tullberg et al. 2018 <sup>[[#fn:r416|416]]</sup> ).

Biochar has the potential to benefit climate adaptation by improving the resilience of food crop production systems to future climate change by increasing yield in some regions and improving water holding capacity (Woolf et al. 2010 <sup>[[#fn:r417|417]]</sup> ; Sohi 2012 <sup>[[#fn:r418|418]]</sup> ) (Chapter 2 and Section 6.4). By increasing yield by 25% in the tropics (Jeffery et al. 2017 <sup>[[#fn:r419|419]]</sup> ), this could increase food production for 3.2 billion people affected by land degradation (IPBES 2018 <sup>[[#fn:r420|420]]</sup> ), thereby potentially improving their resilience to climate change shocks (Table 6.23). A requirement for large areas of land to provide feedstock for biochar could adversely impact on adaptation, though this has not been quantified globally.

Table 6.23 summarises the potentials for adaptation for soil-based response options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-6"></div>

<span id="table-6.23"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.23'''

<span id="adaptation-effects-of-response-options-based-on-land-management-of-soils."></span>
<!-- IMG CAPTION -->
'''Adaptation effects of response options based on land management of soils.'''
<!-- IMG FILE -->
[[File:e17ad56d545e3fd32008a48e73065f5b table-6.23.png]]

<!-- END IMG -->
<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-7"></div>

''Integrated response options based on land management across all/other ecosystems''

For fire management, Doerr et al. (2016) showed that the number of people killed by wildfire was 1940, and the total number of people affected was 5.8 million from 1984 to 2013, globally. Johnston et al. (2012) <sup>[[#fn:r421|421]]</sup> showed that the average mortality attributable to landscape fire smoke exposure was 339,000 deaths annually. The regions most affected were sub-Saharan Africa (157,000) and Southeast Asia (110,000). Estimated annual mortality during La Niña was 262,000, compared with around 100,000 excess deaths across Indonesia, Malaysia and Singapore (Table 6.24).

Management of landslides and natural hazards are usually listed among planned adaptation options in mountainous and sloped hilly areas, where uncontrolled runoff and avalanches may cause climatic disasters, affecting millions of people from both urban and rural areas. Landslide control requires increasing plant cover and engineering practices (see Table 6.8).

For management of pollution, including acidification, Anenberg et al. (2012) estimated that, for particulate matter (PM2.5) and ozone, respectively, fully implementing reduction measures could reduce global population-weighted average surface concentrations by 23–34% and 7–17% and avoid 0.6–4.4 and 0.04–0.52 million annual premature deaths globally in 2030. UNEP and WMO (2011) <sup>[[#fn:r422|422]]</sup> considered emission control measures to reduce ozone and black carbon (BC) and estimated that 2.4 million annual premature deaths (with a range of 0.7 million to 4.6 million) from outdoor air pollution could be avoided. West et al. (2013) <sup>[[#fn:r423|423]]</sup> estimated global 6 GHG mitigation brings co-benefits for air quality and would avoid 0.5 ± 0.2, 1.3 ± 0.5, and 2.2 ± 0.8 million premature deaths in 2030, 2050, and 2100, respectively.

There are no global data on the impacts of management of invasive species/encroachment on adaptation.

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, so restoration may provide significant benefits for adaptation. The Ramsar Convention on Wetlands covers 1.5 Mkm2 across 1674 sites (Keddy et al. 2009 <sup>[[#fn:r424|424]]</sup> ). Coastal floods currently affect 93–310 million people (in 2010) globally, and this could rise to 600 million people in 2100 with sea level rise, unless adaptation measures are taken (Hinkel et al. 2014 <sup>[[#fn:r425|425]]</sup> ). The proportion of the flood-prone population that could avoid these impacts through restoration of coastal wetlands has not been quantified, but this sets an upper limit.

Avoided peat impacts and peatland restoration can help to regulate water flow and prevent downstream flooding (Munang et al. 2014 <sup>[[#fn:r426|426]]</sup> ), but the global potential (in terms of number of people who could avoid flooding through peatland restoration) has not been quantified.

There are no global estimates about the potential of biodiversity conservation to improve the adaptation and resilience of local communities to climate change, in terms of reducing the number of people affected by natural disasters. Nevertheless, it is widely recognised that biodiversity, ecosystem health and resilience improves the adaptation potential (Jones et al. 2012 <sup>[[#fn:r427|427]]</sup> ). For example, tree species mixture improves the resistance of stands to natural disturbances, such as drought, fires, and windstorms (Jactel et al. 2017 <sup>[[#fn:r428|428]]</sup> ), as well as stability against landslides (Kobayashi and Mori 2017 <sup>[[#fn:r429|429]]</sup> ). Moreover, protected areas play a key role for improving adaptation (Watson et al. 2014 <sup>[[#fn:r430|430]]</sup> ; Lopoukhine et al. 2012 <sup>[[#fn:r431|431]]</sup> ), through reducing water flow, stabilising rock movements, creating physical barriers to coastal erosion, improving resistance to fires, and buffering storm damages (Dudley et al. 2010 <sup>[[#fn:r432|432]]</sup> ). Of the largest urban areas worldwide, 33 out of 105 rely on protected areas for some, or all, of their drinking water (Secretariat of the Convention on Biological Diversity 2008 <sup>[[#fn:r433|433]]</sup> ), indicating that many millions are likely to benefit from conservation practices.

Table 6.24 summarises the potentials for adaptation for soil-based response options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-8"></div>

<span id="table-6.24"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.24'''

<span id="adaptation-effects-of-response-options-based-on-land-management-of-soils.-1"></span>
<!-- IMG CAPTION -->
'''Adaptation effects of response options based on land management of soils.'''
<!-- IMG FILE -->
[[File:42e96631bea8a3f4d82176122e646cf6 table-6.24.png]]

<!-- END IMG -->
<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-9"></div>

''Integrated response options based on land management specifically for CDR''

Enhanced weathering of minerals has been proposed as a mechanism for improving soil health and food security (Beerling et al. 2018 <sup>[[#fn:r434|434]]</sup> ), but there is no literature estimating the global adaptation benefits.

Large-scale bioenergy and BECCS can require substantial amounts of cropland (Popp et al. 2017 <sup>[[#fn:r435|435]]</sup> ; Calvin et al. 2014 <sup>[[#fn:r436|436]]</sup> ; Smith et al. 2016a <sup>[[#fn:r437|437]]</sup> ), forestland (Baker et al. 2019 <sup>[[#fn:r438|438]]</sup> ; Favero and Mendelsohn 2017 <sup>[[#fn:r439|439]]</sup> ), and water (Chaturvedi et al. 2013 <sup>[[#fn:r440|440]]</sup> ; Hejazi et al. 2015 <sup>[[#fn:r441|441]]</sup> ; Popp et al. 2011a <sup>[[#fn:r442|442]]</sup> ; Smith et al. 2016a <sup>[[#fn:r443|443]]</sup> ; Fuss et al. 2018 <sup>[[#fn:r444|444]]</sup> ); suggesting that bioenergy and BECCS could have adverse side effects for adaptation. In some contexts – for example, low inputs of fossil fuels and chemicals, limited irrigation, heat/drought tolerant species, and using marginal land – bioenergy can have co-benefits for adaptation (Dasgupta et al. 2014 <sup>[[#fn:r445|445]]</sup> ; Noble et al. 2014 <sup>[[#fn:r446|446]]</sup> ). However, no studies were found that quantify the magnitude of the effect.

Table 6.25 summarises the impacts on adaptation of land management response options specifically for CDR, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-1-integrated-response-options-based-on-land-management-block-10"></div>

<span id="table-6.25"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.25'''

<span id="adaptation-effects-of-response-options-based-on-land-management-specifically-for-cdr."></span>
<!-- IMG CAPTION -->
'''Adaptation effects of response options based on land management specifically for CDR.'''
<!-- IMG FILE -->
[[File:41476802bdbbbb676d66d2effc65cd50 table-6.25.png]]

<!-- END IMG -->
<div id="section-6-3-2-2-integrated-response-options-based-on-value-chain-management"></div>

<span id="integrated-response-options-based-on-value-chain-management-2"></span>
==== 6.3.2.2 Integrated response options based on value chain management ====

<div id="section-6-3-2-2-integrated-response-options-based-on-value-chain-management-block-1"></div>

In this section, the impacts on climate change adaptation of integrated response options based on value chain management are assessed.

''Integrated response options based on value chain management through demand management''

Decreases in pressure on land and decreases in production intensity associated with sustainable healthy diets or reduced food waste could also benefit adaptation; however, the size of this effect is not well quantified (Muller et al. 2017 <sup>[[#fn:r447|447]]</sup> ).

Reducing food waste losses can relieve pressure on the global freshwater resource, thereby aiding adaptation. Food losses account for 215 km3 yr–1 of freshwater resources, which Kummu et al. (2012) <sup>[[#fn:r448|448]]</sup> report to be about 12–15% of the global consumptive water use.

Given that 35% of the global population is living under high water stress or shortage (Kummu et al. 2010 <sup>[[#fn:r449|449]]</sup> ), reducing food waste could benefit 320–400 million people (12–15% of the 2681 million people affected by water stress/shortage).

While no studies report quantitative estimates of the effect of material substitution on adaptation, the effects are expected to be similar to reforestation and afforestation if the amount of material substitution leads to an increase in forest area. Additionally, some studies indicate that wooden buildings, if properly constructed, could reduce fire risk, compared to steel, which softens when burned (Gustavsson et al. 2006 <sup>[[#fn:r450|450]]</sup> ; Ramage et al. 2017 <sup>[[#fn:r451|451]]</sup> ).

Table 6.26 summarises the impacts on adaptation of demand management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-2-integrated-response-options-based-on-value-chain-management-block-2"></div>

<span id="table-6.26"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.26'''

<span id="adaptation-effects-of-response-options-based-on-demand-management."></span>
<!-- IMG CAPTION -->
'''Adaptation effects of response options based on demand management.'''
<!-- IMG FILE -->
[[File:2074166055c2ce2dd8aaa71a09e5502e table-6.26.png]]

<!-- END IMG -->
<div id="section-6-3-2-2-integrated-response-options-based-on-value-chain-management-block-3"></div>

Integrated response options based on value chain management through supply management

It is estimated that 500 million smallholder farmers depend on agricultural businesses in developing countries (IFAD 2013 <sup>[[#fn:r452|452]]</sup> ), meaning that better promotion of value-added products and improved efficiency and sustainability of food processing and retailing could potentially help up to 500 million people to adapt to climate change. However, figures on how sustainable sourcing in general could help farmers and forest management is mostly unquantified. More than 1 million farmers have currently been certified through various schemes (Tayleur et al. 2017 <sup>[[#fn:r453|453]]</sup> ), but how much this has helped them prepare for adaptation is unknown.

Management of supply chains has the potential to reduce vulnerability to price volatility. Consumers in lower-income countries are most affected by price volatility, with sub-Saharan Africa and South Asia at highest risk (Regmi and Meade 2013 <sup>[[#fn:r454|454]]</sup> ; Fujimori et al. 2019 <sup>[[#fn:r455|455]]</sup> ). However, understanding of the stability of food supply is one of the weakest links in global food system research (Wheeler and von Braun 2013 <sup>[[#fn:r456|456]]</sup> ) as instability is driven by a confluence of factors (Headey and Fan 2008 <sup>[[#fn:r457|457]]</sup> ). Food price spikes in 2007 increased the number of people below the poverty line by between 100 million people (Ivanic and Martin 2008 <sup>[[#fn:r458|458]]</sup> ) and 450 million people (Brinkman et al. 2009 <sup>[[#fn:r459|459]]</sup> ), and caused welfare losses of 3% or more for poor households in many countries (Zezza et al. 2009 <sup>[[#fn:r460|460]]</sup> ). Food price stabilisation by China, India and Indonesia alone in 2007/2008 led to reduced staple food price for 2 billion people (Timmer 2009 <sup>[[#fn:r461|461]]</sup> ). Presumably, spending less on food frees up money for other activities, including adaptation, but it is unknown how much (Zezza et al. 2009 <sup>[[#fn:r462|462]]</sup> ; Ziervogel and Ericksen 2010 <sup>[[#fn:r463|463]]</sup> ). In one example, reduction in staple food price costs to consumers in Bangladesh from food stability policies saved rural households 887 million USD2003 total (Torlesse et al. 2003 <sup>[[#fn:r464|464]]</sup> ). Food supply stability through improved supply chains also potentially reduces conflicts (by avoiding food price riots, which occurred in countries with over 100 million total in population in 2007/2008), and thus increases adaptation capacity (Raleigh et al. 2015 <sup>[[#fn:r465|465]]</sup> ).

There are no global estimates of the contribution of improved food transport and distribution, or of urban food systems, in contributing to adaptation, but since the urban population in 2018 was 4.2 billion people, this sets the upper limit on those who could benefit.

Given that 65% (760 million) of working adults in poverty make a living through agriculture, increased energy efficiency in agriculture could benefit these 760 million people.

Table 6.27 summarises the impacts on adaptation of supply management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-2-integrated-response-options-based-on-value-chain-management-block-4"></div>

<span id="table-6.27"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.27'''

<span id="adaptation-effects-of-response-options-based-on-demand-management.-1"></span>
<!-- IMG CAPTION -->
'''Adaptation effects of response options based on demand management.'''
<!-- IMG FILE -->
[[File:ffa44813cefb593dea340ff3452d6bed table-6.27.png]]

<!-- END IMG -->
<div id="section-6-3-2-3-integrated-response-options-based-on-risk-management"></div>

<span id="integrated-response-options-based-on-risk-management-2"></span>
==== 6.3.2.3 Integrated response options based on risk management ====

<div id="section-6-3-2-3-integrated-response-options-based-on-risk-management-block-1"></div>

In this section, the impacts on climate change adaptation of integrated response options based on risk management are assessed.

Reducing urban sprawl is likely to provide adaptation co-benefits via improved human health (Frumkin 2002 <sup>[[#fn:r466|466]]</sup> ; Anderson 2017 <sup>[[#fn:r467|467]]</sup> ), as sprawl contributes to reduced physical activity, worse air pollution, and exacerbation of urban heat island effects and extreme heat waves (Stone et al. 2010 <sup>[[#fn:r468|468]]</sup> ). The most sprawling cities in the US have experienced extreme heat waves, more than double those of denser cities, and ‘urban albedo and vegetation enhancement strategies have significant potential to reduce heat-related health impacts’ (Stone et al. 2010 <sup>[[#fn:r1258|1258]]</sup> ). Other adaption co-benefits are less well understood. There are likely to be cost savings from managing planning growth (one study found 2% savings in metropolitan budgets, which can then be spent on adaptation planning) (Deal and Schunk 2004 <sup>[[#fn:r469|469]]</sup> ).

Diversification is a major adaptation strategy and form of risk management, as it can help households smooth out income fluctuations and provide a broader range of options for the future (Osbahr et al. 2008 <sup>[[#fn:r470|470]]</sup> ; Adger et al. 2011 <sup>[[#fn:r471|471]]</sup> ; Thornton and Herrero 2014 <sup>[[#fn:r472|472]]</sup> ). Surveys of farmers in climate variable areas find that livelihood diversification is increasingly favoured as an adaptation option (Bryan et al. 2013 <sup>[[#fn:r473|473]]</sup> ), although it is not always successful, since it can increase exposure to climate variability (Adger et al. 2011 <sup>[[#fn:r474|474]]</sup> ). There are more than 570 million small farms in the world (Lowder et al. 2016 <sup>[[#fn:r475|475]]</sup> ), and many millions of smallholder agriculturalists already practice livelihood diversification by engaging in multiple forms of off-farm income (Rigg 2006 <sup>[[#fn:r476|476]]</sup> ). It is not clear, however, how many farmers have not yet practiced diversification and thus how many would be helped by supporting this response option.

Currently, millions of farmers still rely to some degree on local seeds. Use of local seeds can facilitate adaptation for many smallholders, as moving to use of commercial seeds can increase costs for farmers (Howard 2015 <sup>[[#fn:r477|477]]</sup> ). Seed networks and banks protect local agrobiodiversity and landraces, which are important to facilitate adaptation, as local landraces may be resilient to some forms of climate change (Coomes et al. 2015 <sup>[[#fn:r478|478]]</sup> ; Van Niekerk and Wynberg 2017 <sup>[[#fn:r479|479]]</sup> ; Vasconcelos et al. 2013 <sup>[[#fn:r480|480]]</sup> ).

Disaster risk management is an essential part of adaptation strategies. The Famine Early Warning Systems Network funded by the US Agency for International Development (USAID) has operated across three continents since the 1980s, and many millions of people across 34 countries have access to early information on drought. Such information can assist communities and households in adapting to onset conditions (Hillbruner and Moloney 2012 <sup>[[#fn:r481|481]]</sup> ). However, concerns have been raised as to how many people are actually reached by disaster risk management and early warning systems; for example, less than 50% of respondents in Bangladesh had heard a cyclone warning before it hit, even though an early warning system existed (Mahmud and Prowse 2012 <sup>[[#fn:r482|482]]</sup> ). Further, there are concerns that current early warning systems ‘tend to focus on response and recovery rather than on addressing livelihood issues as part of the process of reducing underlying risk factors,’ (Birkmann et al. 2015 <sup>[[#fn:r483|483]]</sup> ), leading to less adaptation potential being realised.

Local risk-sharing instruments like rotating credit or loan groups can help buffer farmers against climate impacts and help facilitate adaptation. Both index and commercial crop insurance offers some potential for adaptation, as it provides a means of buffering and transferring weather risk, saving farmers the cost of crop losses (Meze-Hausken et al. 2009 <sup>[[#fn:r484|484]]</sup> ; Patt et al. 2010 <sup>[[#fn:r485|485]]</sup> ). However, overly subsidised insurance can undermine the market’s role in pricing risks and thus depress more rapid adaptation strategies (Skees and Collier 2012 <sup>[[#fn:r486|486]]</sup> ; Jaworski 2016 <sup>[[#fn:r487|487]]</sup> ) and increase the riskiness of decision-making (McLeman and Smit 2006 <sup>[[#fn:r488|488]]</sup> ). For example, availability of crop insurance was observed to reduce farm-level diversification in the US, a factor cited as increasing adaptive capacity (Sanderson et al. 2013 <sup>[[#fn:r489|489]]</sup> ) and crop insurance-holding soybean farmers in the USA have been less likely to adapt to extreme weather events than those not holding insurance (Annan and Schlenker 2015 <sup>[[#fn:r490|490]]</sup> ). It is unclear how many people worldwide use insurance as an adaptation strategy; Platteau et al. (2017) <sup>[[#fn:r491|491]]</sup> suggest that less than 30% of smallholders take out any form of insurance, but it is likely in the millions.

Table 6.28 summarises the impacts on adaptation of risk management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-2-3-integrated-response-options-based-on-risk-management-block-2"></div>

<span id="table-6.28"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.28'''

<span id="adaptation-effects-of-response-options-based-on-risk-management."></span>
<!-- IMG CAPTION -->
'''Adaptation effects of response options based on risk management.'''
<!-- IMG FILE -->
[[File:085120916297aa18665992d507268dc6 table-6.28.png]]

<!-- END IMG -->
<span id="potential-of-the-integrated-response-options-for-addressing-desertification"></span>
=== 6.3.3 Potential of the integrated response options for addressing desertification ===

<div id="section-6-3-3-potential-of-the-integrated-response-options-for-addressing-desertification-block-1"></div>

In this section, the impacts of integrated response options on desertification are assessed.

<div id="section-6-3-3-1-integrated-response-options-based-on-land-management"></div>

<span id="integrated-response-options-based-on-land-management-3"></span>
==== 6.3.3.1 Integrated response options based on land management ====

<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-1"></div>

In this section, the impacts on desertification of integrated response options based on land management are assessed.

''Integrated response options based on land management in agriculture''

Burney et al. (2010) estimated that an additional global cropland area of 11.11–15.14 Mkm <sup>2</sup> would have been needed if productivity had not increased between 1961 and 2000. Given that agricultural expansion is a main driver of desertification (FAO and ITPS 2015 <sup>[[#fn:r492|492]]</sup> ), increased food productivity could have prevented up to 11.11–15.14 Mkm <sup>2</sup> from exploitation and desertification (Table 6.10).

Improved cropland, livestock and grazing land management are strategic options aimed at prevention of desertification, and may include crop and animal selection, optimised stocking rates, changed tillage and/or cover crops, to land-use shifting from cropland to rangeland, in general targeting increases in ground cover by vegetation, and protection against wind erosion (Schwilch et al. 2014 <sup>[[#fn:r493|493]]</sup> ; Bestelmeyer et al. 2015 <sup>[[#fn:r494|494]]</sup> ). Considering the widespread distribution of deserts and desertified lands globally, more than 10 Mkm <sup>2</sup> could benefit from improved management techniques.

Agroforestry can help stabilise soils to prevent desertification (Section 6.3.2.1), so given that there is around 10 Mkm <sup>2</sup> of land with more than 10% tree cover (Garrity 2012 <sup>[[#fn:r495|495]]</sup> ), agroforestry could benefit up to 10 Mkm <sup>2</sup> of land.

Agricultural diversification to prevent desertification may include the use of crops with manures, legumes, fodder legumes and cover crops combined with conservation tillage systems (Schwilch et al. 2014 <sup>[[#fn:r496|496]]</sup> ). These practices can be considered to be part of improved crop management options (see above) and aim at increasing ground coverage by vegetation and controlling wind erosion losses.

Since shifting from grassland to the annual cultivation of crops increases erosion and soil loss, there are significant benefits for desertification control, by stabilising soils in arid areas (Chapter 3). Cropland expansion during 1985 to 2005 was 359,000 km2, or 17,400 Mkm <sup>2</sup> yr <sup>–1</sup> (Foley et al. 2011). Not all of this expansion will be from grasslands or in desertified areas, but this value sets the maximum contribution of prevention of conversion of grasslands to croplands, a small global benefit for desertification control (Table 6.10).

Integrated water management strategies such as water-use efficiency and irrigation, improve soil health through increase in soil organic matter content, thereby delivering benefits for prevention or reversal of desertification (Baumhardt et al. 2015 <sup>[[#fn:r1259|1259]]</sup> ; Datta et al. 2000 <sup>[[#fn:r497|497]]</sup> ; Evans and Sadler 2008 <sup>[[#fn:r498|498]]</sup> ; He et al. 2015 <sup>[[#fn:r499|499]]</sup> ) (Chapter 3). Climate change will amplify existing stress on water availability and on agricultural systems, particularly in semi-arid environments (IPCC AR5 2014 <sup>[[#fn:r500|500]]</sup> ) (Chapter 3). In 2011, semi-arid ecosystems in the southern hemisphere contributed 51% of the global net carbon sink (Poulter et al. 2014 <sup>[[#fn:r501|501]]</sup> ). These results suggest that arid ecosystems could be an important global carbon sink, depending on soil water availability.

Table 6.29 summarises the impacts on desertification of agricultural options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-2"></div>

<span id="table-6.29"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.29'''

<span id="effects-on-desertification-of-response-options-in-agriculture."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of response options in agriculture.'''
<!-- IMG FILE -->
[[File:a38dc2aad2c6d3cd2a6228ac7b6d8504 table-6.29.png]]

<!-- END IMG -->
<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-3"></div>

''Integrated response options based on land management in forestry''

Forests are important to help to stabilise land and regulate water and microclimate (Locatelli et al. 2015b <sup>[[#fn:r1260|1260]]</sup> ). Based on the extent of dry forest at risk of desertification (Núñez et al. 2010 <sup>[[#fn:r1261|1261]]</sup> ; Bastin et al. 2017 <sup>[[#fn:r1262|1262]]</sup> ), the estimated global potential effect for avoided desertification is large for both forest management and for reduced deforestation and forest degradation when cumulated for at least 20 years (Table 6.30). The uncertainty of these global estimates is high. More robust qualitative and some quantitative estimates are available at regional level. For example, it has been simulated that human activity (i.e., land management) contributed to 26% of the total land reverted from desertification in Northern China between 1981 and 2010 (Xu et al. 2018 <sup>[[#fn:r1263|1263]]</sup> ). In Thailand, it was found that the desertification risk is reduced when the land use is changed from bare lands to agricultural lands and forests, and from non-forests to forests; conversely, the desertification risk increases when converting forests and denuded forests to bare lands (Wijitkosum 2016 <sup>[[#fn:r1264|1264]]</sup> ).

Afforestation, reforestation and forest restoration are land management response options that are used to prevent desertification. Forests tend to maintain water and soil quality by reducing runoff and trapping sediments and nutrients (Medugu et al. 2010 <sup>[[#fn:r505|505]]</sup> ; Salvati et al. 2014 <sup>[[#fn:r506|506]]</sup> ), but planting of non-native species in semi-arid regions can deplete soil water resources if they have high evapotranspiration rates (Zeng et al. 2016 <sup>[[#fn:r507|507]]</sup> ; Yang et al. 2014 <sup>[[#fn:r508|508]]</sup> ). Afforestation and reforestation programmes can be deployed over large areas of the Earth, so can create synergies in areas prone to desertification. Global estimates of land potentially available for afforestation are up to 25.8 Mkm <sup>2</sup> by the end of the century, depending on a variety of assumptions on socio- economic developments and climate policies (Griscom et al. 2017; Kreidenweis et al. 2016 <sup>[[#fn:r509|509]]</sup> ; Popp et al. 2017 <sup>[[#fn:r510|510]]</sup> ). The higher end of this range is achieved under the assumption of a globally uniform reward for carbon uptake in the terrestrial biosphere, and it is halved by considering tropical and subtropical areas only to minimise albedo feedbacks (Kreidenweis et al. 2016 <sup>[[#fn:r511|511]]</sup> ). When safeguards are introduced (e.g., excluding existing cropland for food security, boreal areas, etc.), the area available declines to about 6.8 Mkm <sup>2</sup> (95% confidence interval of 2.3 and 11.25 Mkm <sup>2</sup> ), of which about 4.72 Mkm <sup>2</sup> is in the tropics and 2.06 Mkm <sup>2</sup> is in temperate regions (Griscom et al. 2017 <sup>[[#fn:r512|512]]</sup> ) (Table 6.30).

Table 6.30 summarises the impacts on desertification of forestry options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-4"></div>

<span id="table-6.30"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.30'''

<span id="effects-on-desertification-of-response-options-in-forests."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of response options in forests.'''
<!-- IMG FILE -->
[[File:e5cac25d7ea497673c6cf0b1c27dff1c table-6.30.png]]

<!-- END IMG -->
<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-5"></div>

Integrated response options based on land management of soils

With more than 2.7 billion people affected globally by desertification (IPBES 2018) <sup>[[#fn:r513|513]]</sup> , practices to increase soil organic carbon content are proposed as actions to address desertification, and could be applied to an estimated 11.37 Mkm <sup>2</sup> of desertified soils (Lal 2001 <sup>[[#fn:r514|514]]</sup> ) (Table 6.31).

Control of soil erosion could have large benefits for desertification control. Using figures from FAO et al. (2015) <sup>[[#fn:r515|515]]</sup> , IPBES (2018) <sup>[[#fn:r1270|1270]]</sup> estimated that land losses due to erosion to 2050 are equivalent to 1.5 Mkm2 of land from crop production, or 45,000 km <sup>2</sup> yr <sup>–1</sup> (Foley et al. 2011) so soil erosion control could benefit up to 1.50 Mkm2 of land in the coming decades. Lal (2001) <sup>[[#fn:r517|517]]</sup> estimated that desertification control (using soil erosion control as one intervention) could benefit 11.37 Mkm <sup>2</sup> of desertified land globally (Table 6.10).

Oldeman et al. (1991) estimated that the global extent soil affected by salinisation is 0.77 Mkm <sup>2</sup> yr <sup>–1</sup> ,which sets the upper limit on the area that could benefit from measures to address soil salinisation (Table 6.31).

In degraded arid grasslands, shrublands and rangelands, desertification can be reversed by alleviation of soil compaction through installation of enclosures and removal of domestic livestock (Allington et al. 2010 <sup>[[#fn:r518|518]]</sup> ), but there are no global estimates of potential (Table 6.31).

Biochar could potentially deliver benefits in efforts to address desertification though improving water-holding capacity (Woolf et al. 2010 <sup>[[#fn:r519|519]]</sup> ; Sohi 2012 <sup>[[#fn:r520|520]]</sup> ), but the global effect is not quantified.

Table 6.31 summarises the impacts on desertification of soil-based options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-6"></div>

<span id="table-6.31"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.31'''

<span id="effects-on-desertification-of-land-management-of-soils."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of land management of soils.'''
<!-- IMG FILE -->
[[File:78d2a145927ec6536b631d7d7061922e table-6.31.png]]

<!-- END IMG -->
<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-7"></div>

Integrated response options based on land management across all/other ecosystems

For fire management, Arora and Melton (2018) <sup>[[#fn:r521|521]]</sup> estimated, using models and GFED4.1s0 data, that burned area over the 1997–2014 period was 4.834–4.855 Mkm <sup>2</sup> yr <sup>–1</sup> . Randerson et al. (2012) <sup>[[#fn:r522|522]]</sup> estimated small fires increased total burned area globally by 35% from 3.45 to 4.64 Mkm <sup>2</sup> yr <sup>–1</sup> during the period 2001–2010. Tansey et al. (2004) <sup>[[#fn:r523|523]]</sup> estimated that over 3.5 Mkm <sup>2</sup> yr <sup>–1</sup> of burned areas were detected in the year 2000 (Table 6.32).

Although slope and slope aspect are predictive factors of desertification occurrence, the factors with the greatest influence are land cover factors, such as normalised difference vegetation index (NDVI) and rangeland classes (Djeddaoui et al. 2017 <sup>[[#fn:r524|524]]</sup> ). Therefore, prevention of landslides and natural hazards exert indirect influence on the occurrence of desertification.

The global extent of chemical soil degradation (salinisation, pollution and acidification) is about 1.03 Mkm <sup>2</sup> yr <sup>–1</sup> (Oldeman et al. 1991 <sup>[[#fn:r525|525]]</sup> ), giving the maximum extent of land that could benefit from the management of pollution and acidification.

There are no global data on the impacts of management of invasive species/encroachment on desertification, though the impact is presumed to be positive. There are no studies examining the potential role of restoration and avoided conversion of coastal wetlands on desertification.

There are no impacts of peatland restoration for prevention of desertification, as peatlands occur in wet areas and deserts in arid areas, so they are not connected.

For management of pollution, including acidification, Oldeman et al. (1991) estimated the global extent of chemical soil degradation, with 0.77 Mkm <sup>2</sup> yr <sup>–1</sup> affected by salinisation, 0.21 Mkm <sup>2</sup> yr <sup>–1</sup> affected by pollution, and 0.06 Mkm <sup>2</sup> yr <sup>–1</sup> affected by acidification (total: 1.03 Mkm <sup>2</sup> yr <sup>–1</sup> ), so this is the area that could potentially benefit from pollution management measures.

Biodiversity conservation measures can interact with desertification, but the literature contains no global estimates of potential.

Table 6.32 summarises the impacts on desertification of options on all/other ecosystems, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-8"></div>

<span id="table-6.32"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.32'''

<span id="effects-on-desertification-of-response-options-on-allother-ecosystems."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of response options on all/other ecosystems.'''
<!-- IMG FILE -->
[[File:230e6fb72e32c58aae6448e287e45a36 table-6.32.png]]

<!-- END IMG -->
<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-9"></div>

''Integrated response options based on land management specifically for carbon dioxide removal (CDR)''

While spreading of crushed minerals onto land as part of enhanced weathering may provide soil/plant nutrients in nutrient-depleted soils (Beerling et al. 2018), there is no literature reporting on the potential global impacts of this in addressing desertification.

Large-scale production of bioenergy can require significant amounts of land (Smith et al. 2016a <sup>[[#fn:r527|527]]</sup> ; Clarke et al. 2014 <sup>[[#fn:r528|528]]</sup> ; Popp et al. 2017 <sup>[[#fn:r529|529]]</sup> ), with as much as 15 Mkm <sup>2</sup> in 2100 in 2°C scenarios (Popp et al. 2017 <sup>[[#fn:r530|530]]</sup> ), increasing pressures for desertification (Table 6.33).

Table 6.33 summarises the impacts on desertification of options specifically for CDR, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-1-integrated-response-options-based-on-land-management-block-10"></div>

<span id="table-6.33"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.33'''

<span id="effects-on-desertification-of-response-options-specifically-for-cdr."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of response options specifically for CDR.'''
<!-- IMG FILE -->
[[File:19b9e5baaaccdc6be3ef4823f0233e88 table-6.33.png]]

<!-- END IMG -->
<div id="section-6-3-3-2-integrated-response-options-based-on-value-chain-management"></div>

<span id="integrated-response-options-based-on-value-chain-management-3"></span>
==== 6.3.3.2 Integrated response options based on value chain management ====

<div id="section-6-3-3-2-integrated-response-options-based-on-value-chain-management-block-1"></div>

In this section, the impacts on desertification of integrated response options based on value chain management are assessed.

''Integrated response options based on value chain management through demand management''

Dietary change and waste reduction both result in decreased cropland and pasture extent (Bajželj et al. 2014a <sup>[[#fn:r531|531]]</sup> ; Stehfest et al. 2009 <sup>[[#fn:r532|532]]</sup> ; Tilman and Clark 2014 <sup>[[#fn:r533|533]]</sup> ), reducing the pressure for desertification (Table 6.34).

Reduced post-harvest losses could spare 1.98 Mkm2 of cropland globally (Kummu et al. 2012 <sup>[[#fn:r534|534]]</sup> ). Not all of this land could be subject to desertification pressure, so this represents the maximum area that could be relieved from desertification pressure by reduction of post- harvest losses. No studies were found linking material substitution to desertification.

Table 6.34 summarises the impacts on desertification of demand management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-2-integrated-response-options-based-on-value-chain-management-block-2"></div>

<span id="table-6.34"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.34'''

<span id="effects-on-desertification-of-response-options-based-on-demand-management."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of response options based on demand management.'''
<!-- IMG FILE -->
[[File:10785907a8ee8f72c471adc2b802b7f7 table-6.34.png]]

<!-- END IMG -->
<div id="section-6-3-3-2-integrated-response-options-based-on-value-chain-management-block-3"></div>

''Integrated response options based on value chain management through supply management''

There are no global estimates of the impact on desertification of sustainable sourcing, management of supply chains, enhanced urban food systems, improved food processing, or improved energy use in agriculture.

Table 6.35 summarises the impacts on desertification of supply management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-2-integrated-response-options-based-on-value-chain-management-block-4"></div>

<span id="table-6.35"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.35'''

<span id="effects-on-desertification-of-response-options-based-on-supply-management."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of response options based on supply management.'''
<!-- IMG FILE -->
[[File:0e062d581ce2b222eea5da7795af63fb table-6.35.png]]

<!-- END IMG -->
<div id="section-6-3-3-3-integrated-response-options-based-on-risk-management"></div>

<span id="integrated-response-options-based-on-risk-management-3"></span>
==== 6.3.3.3 Integrated response options based on risk management ====

<div id="section-6-3-3-3-integrated-response-options-based-on-risk-management-block-1"></div>

In this section, the impacts on desertification of integrated response options based on risk management are assessed. There are regional case studies of urban sprawl contributing to desertification in Mediterranean climates in particular (Barbero-Sierra et al. 2013 <sup>[[#fn:r535|535]]</sup> ; Stellmes et al. 2013 <sup>[[#fn:r536|536]]</sup> ), but no global figures.

Diversification may deliver some benefits for addressing desertification when it involves greater use of tree crops that may reduce the need for tillage (Antwi-Agyei et al. 2014 <sup>[[#fn:r537|537]]</sup> ). Many anti-desertification programmes call for diversification (Stringer et al. 2009 <sup>[[#fn:r538|538]]</sup> ), but there is little evidence on how many households had done so (Herrmann and Hutchinson 2005 <sup>[[#fn:r539|539]]</sup> ). There are no numbers for global impacts.

The literature is unclear on whether the use of local seeds has any relationship to desertification, although some local seeds are more likely to adapt to arid climates and less likely to degrade land than commercially introduced varieties (Mousseau 2015 <sup>[[#fn:r540|540]]</sup> ). Some anti- desertification programmes have also shown more success using local seed varieties (Bassoum and Ghiggi 2010 <sup>[[#fn:r541|541]]</sup> ; Nunes et al. 2016 <sup>[[#fn:r542|542]]</sup> ).

Some disaster risk management approaches can have impacts on reducing desertification, like the Global Drought Early Warning System (GDEWS) (currently in development), which will monitor precipitation, soil moisture, evapotranspiration, river flows, groundwater, agricultural productivity and natural ecosystem health. It may have some potential co-benefits to reduce desertification (Pozzi et al. 2013 <sup>[[#fn:r543|543]]</sup> ). However, there are no figures yet for how much land area will be covered by such early warning systems.

Risk-sharing instruments, such as pooling labour or credit, could help communities invest in anti-desertification actions, but evidence is missing. Commercial crop insurance is likely to deliver no co-benefits for prevention and reversal of desertification, as evidence suggests that subsidised insurance, in particular, can increase crop production in marginal lands. Crop insurance could have been responsible for shifting up to 0.9% of rangelands to cropland in the Upper Midwest of the USA (Claassen et al. 2011a <sup>[[#fn:r544|544]]</sup> ).

Table 6.36 summarises the impact on desertification for options based on risk management, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-3-3-integrated-response-options-based-on-risk-management-block-2"></div>

<span id="table-6.36"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.36'''

<span id="effects-on-desertification-of-response-options-based-on-risk-management."></span>
<!-- IMG CAPTION -->
'''Effects on desertification of response options based on risk management.'''
<!-- IMG FILE -->
[[File:cc74753edfdb369943112d22c14bf9c0 table-6.36.png]]

<!-- END IMG -->
<span id="potential-of-the-integrated-response-options-for-addressing-land-degradation"></span>
=== 6.3.4 Potential of the integrated response options for addressing land degradation ===

<div id="section-6-3-4-potential-of-the-integrated-response-options-for-addressing-land-degradation-block-1"></div>

In this section, the impacts of integrated response options on land degradation are assessed.

<div id="section-6-3-4-1-integrated-response-options-based-on-land-management"></div>

<span id="integrated-response-options-based-on-land-management-4"></span>
==== 6.3.4.1 Integrated response options based on land management ====

<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-1"></div>

In this section, the impacts on land degradation of integrated response options based on land management are assessed.

''Integrated response options based on land management in agriculture''

Burney et al. (2010) <sup>[[#fn:r545|545]]</sup> estimated that an additional global cropland area of 11.11–15.14 Mkm <sup>2</sup> would have been needed if productivity had not increased between 1961 and 2000. As for desertification, given that agricultural expansion is a main driver of land degradation (FAO and ITPS 2015 <sup>[[#fn:r546|546]]</sup> ), increased food productivity has prevented up to 11.11–15.14 Mkm <sup>2</sup> from exploitation and land degradation (Table 6.37).

Land degradation can be addressed by the implementation of improved cropland, livestock and grazing land management practices, such as those outlined in the recently published Voluntary Guidelines for Sustainable Soil Management (FAO 2017b <sup>[[#fn:r547|547]]</sup> ). Each one could potentially affect extensive surfaces, not less than 10 Mkm <sup>2</sup> .

The guidelines include a list of practices aimed at minimising soil erosion, enhancing soil organic matter content, fostering soil nutrient balance and cycles, preventing, minimising and mitigating soil salinisation and alkalinisation, soil contamination, soil acidification, soil sealing, soil compaction, and improving soil water management. Land cover and land cover change are key factors and indicators of land degradation. In many drylands, land cover is threatened by overgrazing, so management of stocking rate and grazing can help to prevent the advance of land degradation (Smith et al. 2016a <sup>[[#fn:r548|548]]</sup> ).

Agroforestry can help stabilise soils to prevent land degradation; so, given that there is around 10 Mkm <sup>2</sup> of land with more than 10% tree cover (Garrity 2012 <sup>[[#fn:r549|549]]</sup> ), agroforestry could benefit up to 10 Mkm <sup>2</sup> of land.

Agricultural diversification usually aims at increasing climate and food security resilience, such as under ‘climate smart agriculture’ approaches (Lipper et al. 2014 <sup>[[#fn:r550|550]]</sup> ). Both objectives are closely related to land degradation prevention, potentially affecting 1–5 Mkm <sup>2</sup> .

Shifting from grassland to tilled crops increases erosion and soil loss, so there are significant benefits for addressing land degradation, by stabilising degraded soils (Chapter 3). Since cropland expansion during 1985 to 2005 was 17,400 km <sup>2</sup> yr <sup>–1</sup> (Foley et al. 2011 <sup>[[#fn:r551|551]]</sup> ) – and not all of this expansion will be from grasslands or degraded land – the maximum contribution of prevention of conversion of grasslands to croplands is 17,400 km2 yr-1 , a small global benefit for control of land degradation (Table 6.37).

Most land degradation processes that are sensitive to climate change pressures (e.g., erosion, decline in soil organic matter, salinisation, waterlogging, drying of wet ecosystems) can benefit from integrated water management. Integrated water management options include management to reduce aquifer and surface water depletion, and to prevent over-extraction, and provide direct co-benefits for prevention of land degradation. Land management practices implemented for climate change mitigation may also affect water resources. Globally, water erosion is estimated to result in the loss of 23–42 MtN and 14.6–26.4 MtP annually (Pierzynski et al. 2017 <sup>[[#fn:r552|552]]</sup> ). Forests influence the storage and flow of water in watersheds (Eisenbies et al. 2007 <sup>[[#fn:r553|553]]</sup> ) and are therefore important for regulating how climate change will impact on landscapes.

Table 6.37 summarises the impact on land degradation of options in agriculture, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-2"></div>

<span id="table-6.37"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.37'''

<span id="effects-on-land-degradation-of-response-options-in-agriculture."></span>
<!-- IMG CAPTION -->
'''Effects on land degradation of response options in agriculture.'''
<!-- IMG FILE -->
[[File:ce08a8d38a43f4686605172dd5294c83 table-6.37.png]]

<!-- END IMG -->
<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-3"></div>

''Integrated response options based on land management in forestry''

Based on the extent of forest exposed to degradation (Gibbs and Salmon 2015 <sup>[[#fn:r554|554]]</sup> ), the estimated global potential effect for reducing land degradation, for example, through reduced soil erosion (Borrelli et al. 2017 <sup>[[#fn:r555|555]]</sup> ), is large for both forest management and for reduced deforestation and forest degradation when cumulated for at least 20 years (Table 6.38). The uncertainty of these global estimates is high. More robust qualitative, and some quantitative, estimates are available at regional level. For example, in Indonesia, Santika et al. (2017) <sup>[[#fn:r556|556]]</sup> demonstrated that reduced deforestation (Sumatra and Kalimantan islands) contributed to significantly reduced land degradation.

Forest restoration is a key option to achieve the overarching frameworks to reduce land degradation at global scale, such as, for example, Zero Net Land Degradation (ZNLD; UNCCD 2012 <sup>[[#fn:r557|557]]</sup> ) and Land Degradation Neutrality (LDN), not only in drylands (Safriel 2017 <sup>[[#fn:r558|558]]</sup> ). Indeed, it has been estimated that more than 20 Mkm <sup>2</sup> are suitable for forest and landscape restoration, of which 15 Mkm <sup>2</sup> may be devoted to mixed plant mosaic restoration (UNCCD 2012 <sup>[[#fn:r559|559]]</sup> ). Moreover, the Bonn Challenge <sup>[[#fn:6|6]]</sup> aims to restore 1.5 Mkm <sup>2</sup> of deforested and degraded land by 2020, and 3.5 Mkm <sup>2</sup> by 2030. Under a restoration and protection scenario (implementing restoration targets), Wolff et al. (2018) <sup>[[#fn:r560|560]]</sup> simulated that there will be a global increase in net tree cover of about 4 Mkm <sup>2</sup> by 2050 (Table 6.38). At local level, Brazil’s Atlantic Restoration Pact aims to restore 0.15 Mkm <sup>2</sup> of forest areas in 40 years (Melo et al. 2013 <sup>[[#fn:r561|561]]</sup> ). The Y Ikatu Xingu campaign (launched in 2004) aims to contain deforestation and forest degradation processes by reversing the liability of 3000 km2 in the Xingu Basin, Brazil (Durigan et al. 2013 <sup>[[#fn:r562|562]]</sup> ).

Afforestation and reforestation are land management options frequently used to address land degradation (see Section 6.3.3.1 for details, and Table 6.38).

Table 6.38 summarises the impact on land degradation of options in forestry, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-4"></div>

<span id="table-6.38"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.38'''

<span id="effects-on-land-degradation-of-response-options-in-forestry."></span>
<!-- IMG CAPTION -->
'''Effects on land degradation of response options in forestry.'''
<!-- IMG FILE -->
[[File:176394ff7527cf49b39f361450230828 table-6.38.png]]

<!-- END IMG -->
<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-5"></div>

''Integrated response options based on land management of soils''

Increasing soil organic matter content is a measure to address land

degradation. With around 120,000 km2 lost to degradation every year, and over 3.2 billion people negatively impacted on by land degradation globally (IPBES 2018 <sup>[[#fn:r563|563]]</sup> ), practices designed to increase soil organic carbon have a large potential to address land degradation, estimated to affect more than 11 Mkm2 globally (Lal 2004 <sup>[[#fn:r564|564]]</sup> ) (Table 6.39).

Control of soil erosion could have large benefits for addressing land degradation. Soil erosion control could benefit up to 1.50 Mkm2 of land to 2050 (IPBES 2018 <sup>[[#fn:r565|565]]</sup> ). Lal (2004) <sup>[[#fn:r1271|1271]]</sup> suggested that interventions to prevent wind and water erosion (two of the four main interventions proposed to address land degradation), could restore 11 Mkm2 of degraded and desertified soils globally (Table 6.39).

Oldeman et al. (1991) <sup>[[#fn:r566|566]]</sup> estimated that the global extent soil affected by salinisation is 0.77 Mkm2 yr-1, which sets the upper limit on the area that could benefit from measures to address soil salinisation (Table 6.39). The global extent of chemical soil degradation (salinisation, pollution and acidification) is about 1.03 Mkm2 (Oldeman et al. 1991) giving the maximum extent of land that could benefit from the management of pollution and acidification.

Biochar could provide moderate benefits for the prevention or reversal of land degradation, by improving water-holding capacity and nutrient- use efficiency, managing heavy metal pollution, and other co-benefits (Sohi 2012 <sup>[[#fn:r567|567]]</sup> ), though the global effects are not quantified.

Table 6.39 summarises the impact on land degradation of soil-based options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-6"></div>

<span id="table-6.39"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.39'''

<span id="effects-on-land-degradation-of-soil-based-response-options."></span>
<!-- IMG CAPTION -->
'''Effects on land degradation of soil-based response options.'''
<!-- IMG FILE -->
[[File:4d141d5b31c83aac0e6ba2e05d98abbe table-6.39.png]]

<!-- END IMG -->
<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-7"></div>

''Integrated response options based on land management across all/other ecosystems''

For fire management, details of estimates of the impact of wildfires (and thereby the potential impact of their suppression) are given in Section 6.3.3.1 (Table 6.40).

Management of landslides and natural hazards aims at controlling a severe land degradation process affecting sloped and hilly areas, many of them with poor rural inhabitants (FAO and ITPS 2015 <sup>[[#fn:r568|568]]</sup> ; Gariano and Guzzetti 2016 <sup>[[#fn:r569|569]]</sup> ), but the global potential has not been quantified.

There are no global data on the impacts of management of invasive species/encroachment on land degradation, though the impact is presumed to be positive.

Since large areas of coastal wetlands are degraded, restoration could potentially deliver moderate benefits for addressing land degradation, with 0.29 Mkm2 globally considered feasible for restoration (Griscom et al. 2017 <sup>[[#fn:r1272|1272]]</sup> ) (Table 6.40).

Table 6.39 summarises the impact on land degradation of soil-based options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

Considering that large areas (0.46 Mkm2) of global peatlands are degraded and considered suitable for restoration (Griscom et al. 2017 <sup>[[#fn:r570|570]]</sup> ), peatland restoration could deliver moderate benefits for addressing land degradation (Table 6.40).

There are no global estimates of the effects of biodiversity conservation on reducing degraded lands. However, at local scale, biodiversity conservation programmes have been demonstrated to stimulate gain of forest cover across large areas over the last three decades (e.g., in China; Zhang et al. 2013 <sup>[[#fn:r571|571]]</sup> ). Management of wild 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 (Cromsigt et al. 2018 <sup>[[#fn:r572|572]]</sup> ).

Table 6.40 summarises the impact on land degradation of options in all/other ecosystems, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-8"></div>

<span id="table-6.40"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.40'''

<span id="effects-on-land-degradation-of-response-options-in-allother-ecosystems."></span>
<!-- IMG CAPTION -->
'''Effects on land degradation of response options in all/other ecosystems.'''
<!-- IMG FILE -->
[[File:867b3200a7bccbdcfa5bb9da98c08b61 table-6.40.png]]

<!-- END IMG -->
<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-9"></div>

''Integrated response options based on land management specifically for carbon dioxide removal (CDR)''

While spreading of crushed minerals onto land as part of enhanced weathering can provide soil/plant nutrients in nutrient-depleted soils, increase soil organic carbon stocks and help to replenish eroded soil (Beerling et al. 2018 <sup>[[#fn:r573|573]]</sup> ), there is no literature on the global potential for addressing land degradation.

Large-scale production of bioenergy can require significant amounts of land (Smith et al. 2016a <sup>[[#fn:r574|574]]</sup> ; Clarke et al. 2014 <sup>[[#fn:r575|575]]</sup> ; Popp et al. 2017 <sup>[[#fn:r576|576]]</sup> ) – as much as 15 Mkm2 in 2°C scenarios (Popp et al. 2017 <sup>[[#fn:r577|577]]</sup> ) – therefore increasing pressures for land conversion and land degradation (Table 6.13). However, bioenergy production can either increase (Robertson et al. 2017b <sup>[[#fn:r578|578]]</sup> ; Mello et al. 2014 <sup>[[#fn:r579|579]]</sup> ) or decrease (FAO 2011b <sup>[[#fn:r580|580]]</sup> ; Lal 2014 <sup>[[#fn:r581|581]]</sup> ) soil organic matter, depending on where it is produced and how it is managed. These effects are not included in the quantification in Table 6.41.

Table 6.41 summarises the impact on land degradation of options thresholds outlined in Table 6.53 in Section 6.3.6, and indicative specifically for CDR, with confidence estimates based on the (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-1-integrated-response-options-based-on-land-management-block-10"></div>

<span id="table-6.41"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.41'''

<span id="effects-on-land-degradation-of-response-options-specifically-for-cdr."></span>
<!-- IMG CAPTION -->
'''Effects on land degradation of response options specifically for CDR.'''
<!-- IMG FILE -->
[[File:ee8550a825ac54d3897f59d3e415183c table-6.41.png]]

<!-- END IMG -->
<div id="section-6-3-4-2-integrated-response-options-based-on-value-chain-management"></div>

<span id="integrated-response-options-based-on-value-chain-management-4"></span>
==== 6.3.4.2 Integrated response options based on value chain management ====

<div id="section-6-3-4-2-integrated-response-options-based-on-value-chain-management-block-1"></div>

In this section, the impacts on land degradation of integrated response options based on value chain management are assessed.

''Integrated response options based on value chain management through demand management''

Dietary change and waste reduction both result in decreased cropland and pasture extent (Bajželj et al. 2014a <sup>[[#fn:r582|582]]</sup> ; Stehfest et al. 2009 <sup>[[#fn:r583|583]]</sup> ; Tilman and Clark 2014) <sup>[[#fn:r584|584]]</sup> , reducing the pressure for land degradation (Table 6.15). Reduced post-harvest losses could spare 1.98 Mkm2 of cropland globally (Kummu et al. 2012 <sup>[[#fn:r585|585]]</sup> ) meaning that land degradation pressure could be relieved from this land area through reduction of post-harvest losses. The effects of material substitution on land degradation depend on management practice; some forms of logging can lead to increased land degradation (Chapter 4).

Table 6.42 summarises the impact on land degradation of demand management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-2-integrated-response-options-based-on-value-chain-management-block-2"></div>

<span id="table-6.42"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.42'''

<span id="effects-on-land-degradation-of-response-options-based-on-demand-management."></span>
<!-- IMG CAPTION -->
'''Effects on land degradation of response options based on demand management.'''
<!-- IMG FILE -->
[[File:7a5f902d235990a457db94ab84a0ab77 table-6.42.png]]

<!-- END IMG -->
<div id="section-6-3-4-2-integrated-response-options-based-on-value-chain-management-block-3"></div>

Integrated response options based on value chain management through supply management

There are no global estimates of the impact on land degradation of enhanced urban food systems, improved food processing, retailing, or improved energy use in food systems.

There is evidence that sustainable sourcing could reduce land degradation, as the explicit goal of sustainable certification programmes is often to reduce deforestation or other unsustainable land uses. Over 4 Mkm2 of forests are certified for sustainable harvesting (PEFC and FSC 2018 <sup>[[#fn:r586|586]]</sup> ), although it is not clear if all these lands would be at risk of degradation without certification. While the food price instability of 2007/2008 increased financial investment in crop expansion (especially through so-called land grabbing), and thus better management of supply chains might have reduced this amount, no quantification of the total amount of land acquired, nor the possible impact of this crop expansion on degradation, has been recorded (McMichael and Schneider 2011 <sup>[[#fn:r587|587]]</sup> ; McMichael 2012 <sup>[[#fn:r588|588]]</sup> ).

Table 6.43 summarises the impact on land degradation of supply management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-2-integrated-response-options-based-on-value-chain-management-block-4"></div>

<span id="table-6.43"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.43'''

<span id="effects-on-land-degradation-of-response-options-based-on-supply-management."></span>
<!-- IMG CAPTION -->
'''Effects on land degradation of response options based on supply management.'''
<!-- IMG FILE -->
[[File:0224bf59dd4b0028dc73be55e0c4cb79 table-6.43.png]]

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<div id="section-6-3-4-3-integrated-response-options-based-on-risk-management"></div>

<span id="integrated-response-options-based-on-risk-management-4"></span>
==== 6.3.4.3 Integrated response options based on risk management ====

<div id="section-6-3-4-3-integrated-response-options-based-on-risk-management-block-1"></div>

In this section, the impacts on land degradation of integrated response options based on risk management are assessed.

Urban expansion has been identified as a major culprit in soil degradation in some countries; for example, urban expansion in China has now affected 0.2 Mkm2, or almost one-sixth of the cultivated land

total, causing an annual grain yield loss of up to 10 Mt, or around 5–6% of cropland production. Cropland production losses of 8–10% by 2030 are expected under model scenarios of urban expansion (Bren d’Amour et al. 2016 <sup>[[#fn:r589|589]]</sup> ). Pollution from urban development has included water and soil pollution from industry, and wastes and sewage, as well as acid deposition from increasing energy use in cities (Chen 2007) <sup>[[#fn:r590|590]]</sup> , all resulting in major losses to Nature’s Contributions to People from urban conversion (Song and Deng 2015 <sup>[[#fn:r591|591]]</sup> ). Soil sealing from urban expansion is a major loss of soil productivity across many areas. The World Bank has estimated that new city dwellers in developing countries will require 160–500 m2 per capita, converted from non-urban to urban land (Barbero-Sierra et al. 2013 <sup>[[#fn:r592|592]]</sup> ; Angel et al. 2005 <sup>[[#fn:r593|593]]</sup> ).

Degradation can be a driver leading to livelihood diversification (Batterbury 2001 <sup>[[#fn:r594|594]]</sup> ; Lestrelin and Giordano 2007 <sup>[[#fn:r595|595]]</sup> ). Diversification has the potential to deliver some reversal of land degradation, if diversification involves adding non-traditional crops or trees that may reduce the need for tillage (Antwi-Agyei et al. 2014 <sup>[[#fn:r596|596]]</sup> ). China’s Sloping Land Conversion Program has had livelihood diversification benefits and is said to have prevented degradation of 93,000 km2 of land (Liu et al. 2015 <sup>[[#fn:r597|597]]</sup> ). However, Warren (2002) <sup>[[#fn:r598|598]]</sup> provides conflicting evidence that more diverse-income households had increased degradation on their lands in Niger. Palacios et al. (2013) associate landscape fragmentation with increased livelihood diversification in Mexico.

Use of local seeds may play a role in addressing land degradation due to the likelihood of local seeds being less dependent on inputs such as chemical fertilisers or mechanical tillage; for example, in India, local legumes are retained in seed networks while commercial crops like sorghum and rice dominate food markets (Reisman 2017 <sup>[[#fn:r599|599]]</sup> ). However, there are no global figures.

Disaster Risk Management systems can have some positive impacts on prevention and reversal of land degradation, such as the Global Drought Early Warning System (Pozzi et al. 2013 <sup>[[#fn:r600|600]]</sup> ) (Section 6.3.3.3).

Risk-sharing instruments could have benefits for reduced degradation, but there are no global estimates. Commercial crop insurance is likely to deliver no co-benefits for prevention and reversal of degradation. One study found a 1% increase in farm receipts generated from subsidised farm programmes (including crop insurance and others) increased soil erosion by 0.3 t ha–1 (Goodwin and Smith 2003 <sup>[[#fn:r601|601]]</sup> ). Wright and Wimberly (2013) <sup>[[#fn:r602|602]]</sup> found a 5310 km2 decline in grasslands in the Upper Midwest of the USA during 2006–2010, due to crop conversion driven by higher prices and access to insurance.

Table 6.44 summarises the impact on land degradation of risk management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-4-3-integrated-response-options-based-on-risk-management-block-2"></div>

<span id="table-6.44"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.44'''

<span id="effects-on-land-degradation-of-response-options-based-on-risk-management."></span>
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'''Effects on land degradation of response options based on risk management.'''
<!-- IMG FILE -->
[[File:4c2e1fb8c62969b9a6374562f2e5948b table-6.44.png]]

<!-- END IMG -->
<span id="potential-of-the-integrated-response-options-for-addressing-food-security"></span>
=== 6.3.5 Potential of the integrated response options for addressing food security ===

<div id="section-6-3-5-potential-of-the-integrated-response-options-for-addressing-food-security-block-1"></div>

In this section, the impacts of integrated response options on food security are assessed.

<div id="section-6-3-5-1-integrated-response-options-based-on-land-management"></div>

<span id="integrated-response-options-based-on-land-management-5"></span>
==== 6.3.5.1 Integrated response options based on land management ====

<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-1"></div>

In this section, the impacts on food security of integrated response options based on land management are assessed.

''Integrated response options based on land management in agriculture''

Increased food productivity has fed many millions of people who would otherwise not have been fed. Erisman et al. (2008) <sup>[[#fn:r603|603]]</sup> estimated that more than 3 billion people worldwide could not have been fed without 6 increased food productivity arising from nitrogen fertilisation (Table 6.45).

Improved cropland management to achieve food security aims at closing yield gaps by increasing use efficiency of essential inputs such as water and nutrients. Large production increases (45–70% for most crops) are possible from closing yield gaps to 100% of attainable yield, by increasing fertiliser use and irrigation, but overuse of nutrients could cause adverse environmental impacts (Mueller et al. 2012 <sup>[[#fn:r604|604]]</sup> ). This improvement can impact on 1000 million people.

Improved grazing land management includes grasslands, rangelands and shrublands, and all sites on which pastoralism is practiced. In general terms, continuous grazing may cause severe damage to topsoil quality, for example, through compaction. This damage may be reversed by short grazing-exclusion periods under rotational grazing systems (Greenwood and McKenzie 2001 <sup>[[#fn:r605|605]]</sup> ; Drewry 2006 <sup>[[#fn:r606|606]]</sup> ; Taboada et al. 2011 <sup>[[#fn:r607|607]]</sup> ). Due to the widespread diffusion of pastoralism, improved grassland management may potentially affect more than 1000 million people, many of them under subsistence agricultural systems.

Meat, milk, eggs and other animal products, including fish and other seafoods, will play an important role in achieving food security (Reynolds et al. 2015 <sup>[[#fn:r608|608]]</sup> ). Improved livestock management with different animal types and feeds may also impact on one million people (Herrero et al. 2016 <sup>[[#fn:r609|609]]</sup> ). Ruminants are efficient converters of grass into human-edible energy, and protein and grassland-based food production can produce food with a comparable carbon footprint to mixed systems (O’Mara 2012 <sup>[[#fn:r610|610]]</sup> ). However, in the future, livestock production will increasingly be affected by competition for natural resources, particularly land and water, competition between food and feed, and by the need to operate in a carbon-constrained economy (Thornton et al. 2009 <sup>[[#fn:r611|611]]</sup> ).

Currently, more than 1.3 billion people are on degrading agricultural land, and the combined impacts of climate change and land degradation could reduce global food production by 10% by 2050. Since agroforestry could help to address land degradation, up to 1.3 billion people could benefit in terms of food security through agroforestry.

Agricultural diversification is not always economically viable; technological, biophysical, educational and cultural barriers may emerge that limit the adoption of more diverse farming systems by farmers (Section 6.4.1). Nevertheless, diversification could benefit 1000 million people, many of them under subsistence agricultural systems (Birthal et al. 2015 <sup>[[#fn:r612|612]]</sup> ; Massawe et al. 2016 <sup>[[#fn:r613|613]]</sup> ; Waha et al. 2018 <sup>[[#fn:r614|614]]</sup> ).

Cropland expansion during 1985 to 2005 was 17,000 km2 yr–1 (Foley et al. 2005 <sup>[[#fn:r615|615]]</sup> ). Given that cropland productivity (global average of 250 kg protein ha–1 yr–1 for wheat; Clark and Tilman 2017 <sup>[[#fn:r616|616]]</sup> ) is greater than that of grassland (global average of about 10 kg protein ha–1 yr–1 for beef/mutton; Clark and Tilman 2017 <sup>[[#fn:r617|617]]</sup> ), prevention of this conversion to cropland would have led to a loss of about 0.4 Mt protein yr–1 globally. Given an average protein consumption in developing countries of 25.5 kg protein yr–1 (equivalent to 70 g person–1 day–1; FAO 2018b <sup>[[#fn:r618|618]]</sup> ; OECD and FAO 2018 <sup>[[#fn:r619|619]]</sup> ), this is equivalent to the protein consumption of 16.4 million people each year (Table 6.45).

Integrated water management provides direct benefits to food security by improving agricultural productivity (Chapter 5; Godfray and Garnett 2014 <sup>[[#fn:r620|620]]</sup> ; Tilman et al. 2011 <sup>[[#fn:r621|621]]</sup> ), thereby potentially impacting on the livelihood and well-being of more than 1000 million people (Campbell et al. 2016 <sup>[[#fn:r622|622]]</sup> ) affected by hunger and highly impacted on by climate change. Increasing water availability and reliable supply of water for agricultural production using different techniques of water harvesting, storage, and its judicious utilisation through farm ponds, dams and community tanks in rainfed agriculture areas have been presented by Rao et al. (2017a) and Rivera-Ferre et al. (2016) <sup>[[#fn:r623|623]]</sup> .

Table 6.45 summarises the impact on food security of options in agriculture, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-2"></div>

<span id="table-6.45"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.45'''

<span id="effects-on-food-security-of-response-options-in-agriculture."></span>
<!-- IMG CAPTION -->
'''Effects on food security of response options in agriculture.'''
<!-- IMG FILE -->
[[File:bb5f6b277843fe1de66a048c69ee0f04 table-6.45.png]]

<!-- END IMG -->
<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-3"></div>

''Integrated response options based on land management in forestry''

Forests play a major role in providing food to local communities (non-timber forest products, mushrooms, fodder, fruits, berries, etc.), and diversify daily diets directly or indirectly through improving productivity, hunting, diversifying tree-cropland-livestock systems, and grazing in forests. Based on the extent of forest contributing to food supply, considering the people undernourished (FAO et al. 2013 <sup>[[#fn:r624|624]]</sup> ; Rowland et al. 2017 <sup>[[#fn:r625|625]]</sup> ), and the annual deforestation rate (Keenan et al. 2015 <sup>[[#fn:r626|626]]</sup> ), the global potential to enhance food security is moderate for forest management and small for reduced deforestation (Table 6.46). The uncertainty of these global estimates is high. More robust qualitative, and some quantitative, estimates are available at regional level. For example, managed natural forests, shifting cultivation and agroforestry systems are demonstrated to be crucial to food security and nutrition for hundreds of millions of people in rural landscapes worldwide (Sunderland et al. 2013 <sup>[[#fn:r627|627]]</sup> ; Vira et al. 2015 <sup>[[#fn:r628|628]]</sup> ). According to Erb et al. (2016) <sup>[[#fn:r629|629]]</sup> , deforestation would not be needed to feed the global population by 2050, in terms of quantity and quality of food. At local level, Cerri et al. (2018) <sup>[[#fn:r630|630]]</sup> suggested that reduced deforestation, along with integrated cropland-livestock management, would positively impact on more than 120 million people in the Cerrado, Brazil. In Sub-Saharan Africa, where population and food demand are projected to continue to rise substantially, reduced deforestation may have strong positive effects on food security (Doelman et al. 2018 <sup>[[#fn:r631|631]]</sup> ).

Afforestation and reforestation negatively impact on food security (Boysen et al. 2017a; Frank et al. 2017 <sup>[[#fn:r632|632]]</sup> ; Kreidenweis et al. 2016 <sup>[[#fn:r633|633]]</sup> ). It is estimated that large-scale afforestation plans could cause increases in food prices of 80% by 2050 (Kreidenweis et al. 2016 <sup>[[#fn:r634|634]]</sup> ), and more general mitigation measures in the agriculture, forestry and other land-use (AFOLU) sector can translate into a rise in undernourishment of 80–300 million people (Frank et al. 2017 <sup>[[#fn:r635|635]]</sup> ) (Table 6.16). For reforestation, the potential adverse side effects with food security are smaller than afforestation, because forest regrows on recently deforested areas, and its impact would be felt mainly through impeding possible expansion of agricultural areas. On a smaller scale, forested land also offers benefits in terms of food supply, especially when forest is established on degraded land, mangroves and other land that cannot be used for agriculture. For example, food from forests represents a safety net during times of food and income insecurity (Wunder et al. 2014 <sup>[[#fn:r636|636]]</sup> ) and wild harvested meat and freshwater fish provides 30–80% of protein intake for many rural communities (McIntyre et al. 2016 <sup>[[#fn:r637|637]]</sup> ; Nasi et al. 2011 <sup>[[#fn:r638|638]]</sup> ).

Table 6.46 summarises the impact on food security of options in forestry, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-4"></div>

<span id="table-6.46"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.46'''

<span id="effects-on-food-security-of-response-options-in-forestry."></span>
<!-- IMG CAPTION -->
'''Effects on food security of response options in forestry.'''
<!-- IMG FILE -->
[[File:c398aa3e9c42ab13fb11f89a49064697 table-6.46.png]]

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<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-5"></div>

''Integrated response options based on land management of soils''

Increasing soil organic matter stocks can increase yield and improve yield stability (Lal 2006 <sup>[[#fn:r639|639]]</sup> ; Pan et al. 2009 <sup>[[#fn:r640|640]]</sup> ; Soussana et al. 2019 <sup>[[#fn:r641|641]]</sup> ), though this is not universally seen (Hijbeek et al. 2017 <sup>[[#fn:r642|642]]</sup> ), Lal (2006) <sup>[[#fn:r643|643]]</sup> concludes that crop yields can be increased by 20–70 kg ha–1 , 10–50 kg ha–1 and 30–300 kg ha–1 for wheat, rice and maize, respectively, for every 1 tC ha–1 increase in soil organic carbon in the root zone. Increasing soil organic carbon by 1 tC ha–1 could increase food grain production in developing countries by 32 Mt yr–1 (Lal 2006). Frank et al. (2017) estimate that soil carbon sequestration could reduce calorie loss associated with agricultural mitigation measures by 65%, saving 60–225 million people from undernourishment compared to a baseline without soil carbon sequestration (Table 6.47).

Lal (1998) estimated the risks of global annual loss of food production due to accelerated erosion to be as high as 190 Mt yr–1 of cereals, 6 Mt yr–1 of soybean, 3 Mt yr–1 of pulses and 73 Mt yr–1 of roots and tubers. Considering only cereals, if we estimate per-capita annual grain consumption in developing countries to be 300 kg yr–1 (based on data included in FAO 2018b <sup>[[#fn:r644|644]]</sup> ; FAO et al. 2018; Pradhan et al. 2013 <sup>[[#fn:r645|645]]</sup> ; World Bank 2018a <sup>[[#fn:r646|646]]</sup> ), the loss of 190 Mt yr–1 of cereals is equivalent to that consumed by 633 million people, annually (Table 6.47).

Though there are biophysical barriers, such as access to appropriate water sources and limited productivity of salt-tolerant crops, prevention/reversal of soil salinisation could benefit 1–100 million people (Qadir et al. 2013 <sup>[[#fn:r647|647]]</sup> ). Soil compaction affects crop yields, so prevention of compaction could also benefit an estimated 1–100 million people globally (Anderson and Peters 2016 <sup>[[#fn:r648|648]]</sup> ).

Biochar on balance, could provide moderate benefits for food security by improving yields by 25% in the tropics, but with more limited impacts in temperate regions (Jeffery et al. 2017 <sup>[[#fn:r649|649]]</sup> ), or through improved water-holding capacity and nutrient-use efficiency (Sohi 2012 <sup>[[#fn:r650|650]]</sup> ) (Chapter 5). These benefits could, however, be tempered by additional pressure on land if large quantities of biomass are required as feedstock for biochar production, thereby causing potential conflicts with food security (Smith 2016 <sup>[[#fn:r651|651]]</sup> ). Smith (2016) <sup>[[#fn:r652|652]]</sup> estimated that 0.4–2.6 Mkm2 of land would be required for biomass feedstock to deliver 2.57 GtCO2e yr–1 of CO2 removal. If biomass production occupied 2.6 Mkm2 of cropland, equivalent to around 20% of the global cropland area, this could potentially have a large effect on food security, although Woolf et al. (2010) <sup>[[#fn:r653|653]]</sup> argue that abandoned cropland could be used to supply biomass for biochar, thus avoiding competition with food production. Similarly, Woods et al. (2015) estimate that 5–9 Mkm2 of land is available for biomass production without compromising food security and biodiversity, considering marginal and degraded land and land released by pasture intensification (Table 6.47).

Table 6.47 summarises the impact on food security of soil-based options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-6"></div>

<span id="table-6.47"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.47'''

<span id="effects-on-food-security-of-soil-based-response-options."></span>
<!-- IMG CAPTION -->
'''Effects on food security of soil-based response options.'''
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[[File:01de0eb3780a3277292d0d22947f5223 table-6.47.png]]

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<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-7"></div>

''Integrated response options based on land management across all/other ecosystems''

FAO (2015) <sup>[[#fn:r654|654]]</sup> calculated that damage from forest fires between 2003 and 2013 impacted on a total of 49,000 km2 of crops, with the vast majority in Latin America. Based on the world cereal yield in 2013 reported by Word Bank (2018b) (3.8 t ha–1), the loss of 49,000 km2 of crops is equivalent to 18.6 Mt yr–1 of cereals lost. Assuming annual grain consumption per capita to be 300 kg yr–1 (estimated, based on data included in FAO 2018b; FAO et al. 2018; Pradhan et al. 2013 <sup>[[#fn:r655|655]]</sup> ; World Bank 2018a <sup>[[#fn:r656|656]]</sup> ), the loss of 18.6 Mt yr–1 would remove cereal crops equivalent to that consumed by 62 million people (Table 6.48).

Landslides and other natural hazards affect 1–100 million people globally, so preventing them could provide food security benefits to these people.

In terms of measures to tackle pollution, including acidification, Shindell et al. (2012) <sup>[[#fn:r657|657]]</sup> considered about 400 emission control measures to reduce ozone and black carbon (BC). This strategy increases annual crop yields by 30–135 Mt due to ozone reductions in 2030 and beyond. If annual grain consumption per capita is assumed as 300 kg yr–1 (estimated based on data included in FAO 2018b <sup>[[#fn:r658|658]]</sup> ; FAO et al. 2018; Pradhan et al. 2013 <sup>[[#fn:r659|659]]</sup> ; World Bank 2018a <sup>[[#fn:r660|660]]</sup> ), increase in annual crop yields by 30–135 Mt would feed 100–450 million people.

There are no global data on the impacts of management of invasive species/encroachment on food security.

Since large areas of converted coastal wetlands are used for food production (e.g., mangroves converted for aquaculture; Naylor et al. 2000 <sup>[[#fn:r661|661]]</sup> ), restoration of coastal wetlands could displace food production and damage local food supply, potentially leading to adverse impacts on food security. However, these effects are likely to be very small, given that only 0.3% of human food comes from the oceans and other aquatic ecosystems (Pimentel 2006 <sup>[[#fn:r662|662]]</sup> ), and that the impacts could be offset by careful management, such as the careful siting of ponds within mangroves (Naylor et al. 2000 <sup>[[#fn:r663|663]]</sup> ) (Table 6.46).

Around 14–20% (0.56–0.80 Mkm2) of the global 4 Mkm2 of peatlands are used for agriculture, mostly for meadows and pasture, meaning that, if all of these peatlands were removed from production, 0.56–0.80 Mkm2 of agricultural land would be lost. Assuming livestock production on this land (since it is mostly meadow and pasture) with a mean productivity of 9.8 kg protein ha–1 yr–1 (calculated from land footprint of beef/mutton (Clark and Tilman 2017), and average protein consumption in developing countries of 25.5 kg protein yr–1 (equivalent to 70 g per person per day; (FAO 2018b; OECD and FAO 2018 <sup>[[#fn:r664|664]]</sup> )), this would be equivalent to 21–31 million people no longer fed from this land (Table 6.46)).

There are no global estimates on how biodiversity conservation improves nutrition (i.e., the number of nourished people). Biodiversity, and its management, is crucial for improving sustainable and diversified diets (Global Panel on Agriculture and Food Systems for Nutrition 2016 <sup>[[#fn:r665|665]]</sup> ). Indirectly, the loss of pollinators (due to combined causes, including the loss of habitats and flowering species) would contribute to 1.42 million additional deaths per year from non- communicable and malnutrition-related diseases, and 27.0 million lost disability-adjusted life years (DALYs) per year (Smith et al. 2015 <sup>[[#fn:r666|666]]</sup> ). However, at the same time, some options to preserve biodiversity, like protected areas, may potentially conflict with food production by local communities (Molotoks et al. 2017 <sup>[[#fn:r667|667]]</sup> ).

Table 6.48 summarises the impact on food security of response options in all/other ecosystems, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence is based.

<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-8"></div>

<span id="table-6.48"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.48'''

<span id="effects-on-food-security-of-response-options-in-allother-ecosystems."></span>
<!-- IMG CAPTION -->
'''Effects on food security of response options in all/other ecosystems.'''
<!-- IMG FILE -->
[[File:7f7d277492151c455d3c89e95c76870a table-6.48.png]]

<!-- END IMG -->
<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-9"></div>

Integrated response options based on land management specifically for CDR

The spreading of crushed minerals on land as part of enhanced weathering on nutrient-depleted soils can potentially increase crop yield by replenishing plant available silicon, potassium and other plant nutrients (Beerling et al. 2018 <sup>[[#fn:r668|668]]</sup> ), but there are no estimates in the literature reporting the potential magnitude of this effect on global food production.

Competition for land between bioenergy and food crops can lead to adverse side effects for food security. Many studies indicate that bioenergy could increase food prices (Calvin et al. 2014 <sup>[[#fn:r669|669]]</sup> ; Popp et al. 2017 <sup>[[#fn:r670|670]]</sup> ; Wise et al. 2009 <sup>[[#fn:r671|671]]</sup> ). Only three studies were found linking bioenergy to the population at risk of hunger; they estimate an increase in the population at risk of hunger of between 2 million and 150 million people (Table 6.49).

Table 6.49 summarises the impact on food security of response options specifically for CDR, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-5-1-integrated-response-options-based-on-land-management-block-10"></div>

<span id="table-6.49"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.49'''

<span id="effects-on-food-security-of-response-options-specifically-for-cdr."></span>
<!-- IMG CAPTION -->
'''Effects on food security of response options specifically for CDR.'''
<!-- IMG FILE -->
[[File:e833b3721338a063bf6ca137bd20a0c1 table-6.49.png]]

<!-- END IMG -->
<div id="section-6-3-5-2-integrated-response-options-based-on-value-chain-management"></div>

<span id="integrated-response-options-based-on-value-chain-management-5"></span>
==== 6.3.5.2 Integrated response options based on value chain management ====

<div id="section-6-3-5-2-integrated-response-options-based-on-value-chain-management-block-1"></div>

In this section, the impacts on food security of integrated response options based on value chain management are assessed.

''Integrated response options based on value chain management through demand management''

Dietary change can free up agricultural land for additional production (Bajželj et al. 2014a <sup>[[#fn:r672|672]]</sup> ; Stehfest et al. 2009 <sup>[[#fn:r673|673]]</sup> ; Tilman and Clark 2014 <sup>[[#fn:r674|674]]</sup> ) and reduce the risk of some diseases (Tilman and Clark 2014 <sup>[[#fn:r675|675]]</sup> ; Aleksandrowicz et al. 2016 <sup>[[#fn:r676|676]]</sup> ), with large positive impacts on food security (Table 6.50).

Kummu et al. (2012) <sup>[[#fn:r1273|1273]]</sup> estimate that an additional billion people could be fed if food waste was halved globally. This includes both post- harvest losses and retail and consumer waste. Measures such as improved food transport and distribution could also contribute to this waste reduction (Table 6.50).

While no studies quantified the effect of material substitution on food security, the effects are expected to be similar to reforestation and afforestation if the amount of material substitution leads to an increase in forest area.

Table 6.50 summarises the impact on food security of demand management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-5-2-integrated-response-options-based-on-value-chain-management-block-2"></div>

<span id="table-6.50"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.50'''

<span id="effects-on-food-security-of-demand-management-options."></span>
<!-- IMG CAPTION -->
'''Effects on food security of demand management options.'''
<!-- IMG FILE -->
[[File:08e041c5e0015ce17f95423353823e62 table-6.50.png]]

<!-- END IMG -->
<div id="section-6-3-5-2-integrated-response-options-based-on-value-chain-management-block-3"></div>

Integrated response options based on value chain management through supply management

Since 810 million people are undernourished (FAO 2018b <sup>[[#fn:r677|677]]</sup> ), this sets the maximum number of those who could potentially benefit from sustainable sourcing or better management of supply chains. Currently, however, only 1 million people are estimated to benefit from sustainable sourcing (Tayleur et al. 2017 <sup>[[#fn:r678|678]]</sup> ). For the others, food price spikes affect food security and health; there are clearly documented effects of stunting among young children as a result of the 2007/2008 food supply crisis (de Brauw 2011 <sup>[[#fn:r679|679]]</sup> ; Arndt et al. 2016 <sup>[[#fn:r680|680]]</sup> ; Brinkman et al. 2009 <sup>[[#fn:r681|681]]</sup> ; Darnton-Hill and Cogill 2010 <sup>[[#fn:r682|682]]</sup> ) with a 10% increase in wasting attributed to the crisis in South Asia (Vellakkal et al. 2015 <sup>[[#fn:r683|683]]</sup> ). There is conflicting evidence on the impacts of different food price stability options for supply chains, and little quantification (Byerlee et al. 2006 <sup>[[#fn:r684|684]]</sup> ; del Ninno et al. 2007 <sup>[[#fn:r685|685]]</sup> ; Alderman 2010 <sup>[[#fn:r686|686]]</sup> ; Braun et al. 2014 <sup>[[#fn:r687|687]]</sup> ). Reduction in staple food prices due to price stabilisation resulted in more expenditure on other foods and increased nutrition (e.g., oils, animal products), leading to a 10% reduction in malnutrition among children in one study (Torlesse et al. 2003 <sup>[[#fn:r688|688]]</sup> ). Comparison of two African countries shows that protectionist policies (food price controls) and safety nets to reduce price instability resulted in a 20% decrease in risk of malnutrition (Nandy et al. 2016 <sup>[[#fn:r689|689]]</sup> ). Models using policies for food aid and domestic food reserves to achieve food supply and price stability showed the most effectiveness of all options in achieving climate mitigation and food security goals (e.g., more effective than carbon taxes) as they did not exacerbate food insecurity and did not reduce ambitions for achieving temperature goals (Fujimori et al. 2019 <sup>[[#fn:r690|690]]</sup> ).

For urban food systems, increased food production in cities, combined with governance systems for distribution and access can improve food security, with a potential to produce 30% of food consumed in cities. The urban population in 2018 was 4.2 billion people, so 30% represents 1230 million people who could benefit in terms of food security from improved urban food systems (Table 6.51).

It is estimated that 500 million smallholder farmers depend on agricultural businesses in developing countries (World Bank 2017 <sup>[[#fn:r691|691]]</sup> ), which sets the maximum number of people who could benefit from improved efficiency and sustainability of food processing, retail and agri-food industries.

Up to 2500 million people could benefit from increased energy efficiency in agriculture, based on the estimated number of people worldwide lacking access to clean energy and instead relying on biomass fuels for their household energy needs (IEA 2014 <sup>[[#fn:r692|692]]</sup> ).

Table 6.51 summarises the impact on food security of supply management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-5-2-integrated-response-options-based-on-value-chain-management-block-4"></div>

<span id="table-6.51"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.51'''

<span id="effects-on-food-security-of-supply-management-options."></span>
<!-- IMG CAPTION -->
'''Effects on food security of supply management options.'''
<!-- IMG FILE -->
[[File:0601f2fec4d3b6c3b5cd3b38f42e0495 table-6.51.png]]

<!-- END IMG -->
<div id="section-6-3-5-3-integrated-response-options-based-on-risk-management"></div>

<span id="integrated-response-options-based-on-risk-management-5"></span>
==== 6.3.5.3 Integrated response options based on risk management ====

<div id="section-6-3-5-3-integrated-response-options-based-on-risk-management-block-1"></div>

In this section, the impacts on food security of integrated response options based on risk management are assessed.

Evidence in the USA indicates ambiguous trends between sprawl and food security: on the one hand, most urban expansion in the USA has primarily been on lands of low and moderate soil productivity with only 6% of total urban land on highly productive soil; on the other hand, highly productive soils have experienced the highest rate of conversion of any soil type (Nizeyimana et al. 2001 <sup>[[#fn:r693|693]]</sup> ). Specific types of agriculture are often practiced in urban-influenced fringes, such as fruits, vegetables, and poultry and eggs in the USA, the loss of which can have an impact on the types of nutritious foods available in urban areas (Francis et al. 2012 <sup>[[#fn:r694|694]]</sup> ). China is also concerned with food security implications of urban sprawl, and a loss of 30 Mt of grain production from 1998 to 2003 in eastern China was attributed to urbanisation (Chen 2007 <sup>[[#fn:r695|695]]</sup> ). However, overall global quantification has not been attempted.

Diversification is associated with increased welfare and incomes and decreased levels of poverty in several country studies (Arslan et al. 2018 <sup>[[#fn:r696|696]]</sup> ; Asfaw et al. 2018 <sup>[[#fn:r697|697]]</sup> ). These are likely to have large food security benefits (Barrett et al. 2001 <sup>[[#fn:r698|698]]</sup> ; Niehof 2004 <sup>[[#fn:r699|699]]</sup> ), but there is little global quantification.

Local seed use can provide considerable benefits for food security because of the increased ability of farmers to revive and strengthen local food systems (McMichael and Schneider 2011 <sup>[[#fn:r700|700]]</sup> ); studies have reported more diverse and healthy food in areas with strong food sovereignty networks (Coomes et al. 2015 <sup>[[#fn:r701|701]]</sup> ; Bisht et al. 2018 <sup>[[#fn:r702|702]]</sup> ). Women, in particular, may benefit from seed banks for low-value but nutritious crops (Patnaik et al. 2017 <sup>[[#fn:r703|703]]</sup> ). Many hundreds of millions of smallholders still rely on local seeds and they provide for many hundreds of millions of consumers (Altieri et al. 2012 <sup>[[#fn:r704|704]]</sup> ; McGuire and Sperling 2016 <sup>[[#fn:r705|705]]</sup> ). Therefore, keeping their ability to do so through seed sovereignty is important. However, there may be lower food yields from local and unimproved seeds, so the overall impact of local seed use on food security is ambiguous (McGuire and Sperling 2016 <sup>[[#fn:r706|706]]</sup> ).

Disaster risk management approaches can have important impacts on reducing food insecurity, and current warning systems for drought and storms currently reach over 100 million people. When these early warning systems can help farmers harvest crops in advance of impending weather events, or otherwise make agricultural decisions to prepare for adverse events, there are likely to be positive impacts on food security (Fakhruddin et al. 2015 <sup>[[#fn:r707|707]]</sup> ). Surveys with farmers reporting food insecurity from climate impacts have indicated their strong interest in having such early warning systems (Shisanya and Mafongoya 2016 <sup>[[#fn:r708|708]]</sup> ). Additionally, famine early warning systems have been successful in Sahelian Africa to alert authorities of impending food shortages so that food acquisition and transportation from outside the region can begin, potentially helping millions of people (Genesio et al. 2011 <sup>[[#fn:r709|709]]</sup> ; Hillbruner and Moloney 2012 <sup>[[#fn:r710|710]]</sup> ).

Risk-sharing instruments are often aimed at sharing food supplies and reducing risk, and thus are likely to have important, but unquantified, benefits for food security. Crop insurance, in particular, has generally led to (modest) expansions in cultivated land area and increased food production (Claassen et al. 2011a <sup>[[#fn:r711|711]]</sup> ; Goodwin et al. 2004 <sup>[[#fn:r712|712]]</sup> ).

Table 6.52 summarises the impact on food security of risk management options, with confidence estimates based on the thresholds outlined in Table 6.53 in Section 6.3.6, and indicative (not exhaustive) references upon which the evidence in based.

<div id="section-6-3-5-3-integrated-response-options-based-on-risk-management-block-2"></div>

<span id="table-6.52"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.52'''

<span id="effects-on-food-security-of-risk-management-options."></span>
<!-- IMG CAPTION -->
'''Effects on food security of risk management options.'''
<!-- IMG FILE -->
[[File:5f2e2c90759844fe7e364eb13b09a87e table-6.52.png]]

<!-- END IMG -->
<span id="summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security"></span>
=== 6.3.6 Summarising the potential of the integrated response options across mitigation, adaptation, desertification land degradation and food security ===

<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-1"></div>

Using the quantification provided in Tables 6.13 to 6.52, the impacts are categorised as either positive or negative, and are designated as large, moderate and small, according to the criteria given in Table 6.53. <sup>[[#fn:7|7]]</sup>

<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-2"></div>

<span id="table-6.53"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.53'''

<span id="key-for-criteria-used-to-define-the-magnitude-of-the-impact-of-each-integrated-response-option."></span>
<!-- IMG CAPTION -->
'''Key for criteria used to define the magnitude of the impact of each integrated response option.'''
<!-- IMG FILE -->
[[File:28980188e5403b56c78ab5f5bbd774a4 table-6.53.png]]

Note: All numbers are for global scale; all values are for technical potential. For mitigation, the target is set at around the level of large single mitigation measure (about 1 GtC yr–1 = 3.67 GtCO2-eq yr–1) (Pacala and Socolow 2004 <sup>[[#fn:r713|713]]</sup> ), with a combined target to meet 100 GtCO2 in 2100, to go from baseline to 2 ̊C (Clarke et al. 2014 <sup>[[#fn:r714|714]]</sup> ). For adaptation, numbers are set relative to the about 5 million lives lost per year attributable to climate change and a carbon-based economy, with 0.4 million per year attributable directly to climate change. This amounts to 100 million lives predicted to be lost between 2010 and 2030 due to climate change and a carbon-based economy (DARA 2012 <sup>[[#fn:r715|715]]</sup> ), with the largest category representing 25% of this total. For desertification and land degradation, categories are set relative to the 10–60 million km2 of currently degraded land (Gibbs and Salmon 2015 <sup>[[#fn:r716|716]]</sup> ) with the largest category representing 30% of the lower estimate. For food security, categories are set relative to the roughly 800 million people currently undernourished (HLPE 2017 <sup>[[#fn:r717|717]]</sup> ) with the largest category representing around 12.5% of this total.

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-3"></div>

Tables 6.54 to 6.61 summarise the potentials of the integrated response options across mitigation, adaptation, desertification, land degradation and food security. Cell colours correspond to the large, moderate and small impact categories shown in Table 6.53.

As seen in Tables 6.54 to 6.61, three response options across the 14 for which there are data for every land challenge: increased food productivity, agroforestry and increased soil organic carbon content, deliver large benefits across all five land challenges.

A further six response options: improved cropland management, improved grazing land management, improved livestock management, agroforestry, fire management and reduced post-harvest losses, deliver either large or moderate benefits for all land challenges.

Three additional response options: dietary change, reduced food waste and reduced soil salinisation, each missing data to assess global potential for just one of the land challenges, deliver large or moderate benefits to the four challenges for which there are global data.

Eight response options: increased food productivity, reforestation and forest restoration, afforestation, increased soil organic carbon content, enhanced mineral weathering, dietary change, reduced post-harvest losses, and reduced food waste, have large mitigation potential (&gt;3 GtCO2e yr–1) without adverse impacts on other challenges.

Sixteen response options: increased food productivity, improved cropland management, agroforestry, agricultural diversification, forest management, increased soil organic carbon content, reduced landslides and natural hazards, restoration and reduced conversion of coastal wetlands, reduced post-harvest losses, sustainable sourcing, management of supply chains, improved food processing and retailing, improved energy use in food systems, livelihood diversification, use of local seeds, and disaster risk management, have large adaptation potential at global scale (positively affecting more than 25 million people) without adverse side effects for other challenges.

Thirty-three of the 40 response options can be applied without requiring land-use change and limiting available land. A large number of response options do not require dedicated land, including several land management options, all value chain options, and all risk management options. Four options, in particular, could greatly increase competition for land if applied at scale: afforestation, reforestation, and land used to provide feedstock for bioenergy (with or without BECCS) and biochar, with three further options: reduced grassland conversion to croplands, restoration and reduced conversion of peatlands, and restoration and reduced conversion of coastal wetlands having smaller or variable impacts on competition for land. Other options such as reduced deforestation and forest degradation, restrict land conversion for other options and uses.

Some response options can be more effective when applied together – for example, dietary change and waste reduction expand the potential to apply other options by freeing as much as 25 Mkm2 (4–25 Mkm2 for dietary change; Alexander et al. 2016 <sup>[[#fn:r718|718]]</sup> ; Bajželj et al. 2014b <sup>[[#fn:r719|719]]</sup> ; Stehfest et al. 2009 <sup>[[#fn:r720|720]]</sup> ; Tilman and Clark 2014 <sup>[[#fn:r721|721]]</sup> and 7 Mkm2 for reduced food waste; Bajželj et al. 2014b <sup>[[#fn:r722|722]]</sup> ).

In terms of the categories of response options, most agricultural land management response options (all except for reduced grassland conversion to cropland which potentially adversely affects food security), deliver benefits across the five land challenges (Table 6.54). Among the forest land management options, afforestation and reforestation have the potential to deliver large co-benefits across all land challenges except for food security, where these options provide a threat due to competition for land (Table6.55). Among the soil-based response options, some global data are missing, but none except biochar shows any potential for negative impacts, with that potential negative impact arising from additional pressure on land if large quantities of biomass feedstock are required for biochar production (Table 6.56). Where global data exists, most response options in other/all ecosystems deliver benefits, except for a potential moderate negative impact on food security by restoring peatlands currently used for agriculture (Table 6.57). Of the two response options specifically targeted at CDR, there are missing data for enhanced weathering of minerals for three of the challenges, but large-scale bioenergy and BECCS show a potential large benefit for mitigation, but small to large adverse impacts on the other four land challenges (Table 6.58), mainly driven by increased pressure on land due to feedstock demand.

While data allow the impact of material substitution to be assessed only for mitigation, the three other demand-side response options: dietary change, reduced post-harvest losses, and reduced food waste provide large or moderate benefits across all challenges for which data exist (Table 6.59). Data is not available for any of the supply- side response options to assess the impact on more than three of the land challenges, but there are large to moderate benefits for all those for which data are available (Table 6.60). Data are not available to assess the impact of risk-management-based response options on all of the challenges, but there are small to large benefits for all of those for which data are available (Table 6.61).

<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-4"></div>

<span id="table-6.54"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.54'''

<span id="summary-of-direction-and-size-of-impact-of-land-management-options-in-agriculture-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of land management options in agriculture on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:f3c0e6419ac63abc2106409ba2db7df0 table-6.54a.png]] [[File:d0b4834b448ca60acc2e63e64372b77f table-6.54b.png]]

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-5"></div>

<span id="table-6.55"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.55'''

<span id="summary-of-direction-and-size-of-impact-of-land-management-options-in-forests-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of land management options in forests on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:8be8f2c15c0cc575d861005a47ee6d63 table-6.55a.png]] [[File:aa880d40d2aad7fd79d05762f3da6984 table-6.55b.png]]

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-6"></div>

<span id="table-6.56"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.56'''

<span id="summary-of-direction-and-size-of-impact-of-soil-based-land-management-options-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of soil-based land management options on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:a7ff7c756fae09a0320711ded155032a table-6.56a.png]] [[File:39a3dacbfa1e746d5a09e53082add255 table-6.56b.png]]

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-7"></div>

<span id="table-6.57"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.57'''

<span id="summary-of-direction-and-size-of-impact-of-land-management-in-allother-ecosystems-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of land management in all/other ecosystems on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:3e4ce784765ebbc4cbf90be930f3a738 table-6.57a.png]] [[File:a038f5b878d7668733dc7463571f2438 table-6.57b.png]]

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-8"></div>

<span id="table-6.58"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.58'''

<span id="summary-of-direction-and-size-of-impact-of-land-management-options-specifically-for-cdr-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of land management options specifically for CDR on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:2ebdd935055158046b114cce892c1670 table-6.58.png]]

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-9"></div>

<span id="table-6.59"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.59'''

<span id="summary-of-direction-and-size-of-impact-of-demand-management-options-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of demand management options on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:fd314fe24dc9ac436401148d41bbdec5 table-6.59.png]]

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-10"></div>

<span id="table-6.60"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.60'''

<span id="summary-of-direction-and-size-of-impact-of-supply-management-options-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of supply management options on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:517030b36369401d5bba508dfd723de5 table-6.60a.png]] [[File:23e72c125a6072c438f70a4c7d148692 table-6.60b.png]]

<!-- END IMG -->
<div id="section-6-3-6-summarising-the-potential-of-the-integrated-response-options-across-mitigation-adaptation-desertification-land-degradation-and-food-security-block-11"></div>

<span id="table-6.61"></span>
<!-- START IMG -->
<!-- TABLE IMG -->
<!-- IMG TITLE -->
'''Table 6.61'''

<span id="summary-of-direction-and-size-of-impact-of-risk-management-options-on-mitigation-adaptation-desertification-land-degradation-and-food-security."></span>
<!-- IMG CAPTION -->
'''Summary of direction and size of impact of risk management options on mitigation, adaptation, desertification, land degradation and food security.'''
<!-- IMG FILE -->
[[File:c517d06048dad62bfdb3febbcd57ec61 table-6.61a.png]] [[File:85aa21fd5a8b8949f92860e89e1b3b99 table-6.61b.png]]

<!-- END IMG -->
<span id="managing-interactions-and-interlinkages"></span>