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

==== 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]]

<!-- END IMG -->
<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.'''
<!-- IMG FILE -->
[[File:01de0eb3780a3277292d0d22947f5223 table-6.47.png]]

<!-- END IMG -->
<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>