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

=== 5.5.2 Demand-side mitigation options ===

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Although population growth is one of the drivers of global food demand and the resulting environmental burden, demand-side management of the food system could be one of the solutions to curb climate change. Avoiding food waste during consumption, reducing over-consumption, and changing dietary preferences can contribute significantly to providing healthy diets for all, as well as reducing the environmental footprint of the food system. The number of studies addressing this issue have increased in the last few years (Chapter 2). (See Section 5.6 for synergies and trade-offs with health and Section 5.7 for discussion of Just Transitions.)

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==== 5.5.2.1 Mitigation potential of different diets ====

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A systematic review found that higher consumption of animal-based foods was associated with higher estimated environmental impact, whereas increased consumption of plant-based foods was associated with an estimated lower environmental impact (Nelson et al. 2016 <sup>[[#fn:r871|871]]</sup> ). Assessment of individual foods within these broader categories showed that meat – especially ruminant meat (beef and lamb) – was consistently identified as the single food with the greatest impact on the environment, on a global basis, most often in terms of GHG emissions and/or land use.

Figure 5.12 shows the technical mitigation potentials of some scenarios of alternative diets examined in the literature. Stehfest et al. (2009) <sup>[[#fn:r872|872]]</sup> were among the first to examine these questions. They found that under the most extreme scenario, where no animal products are consumed at all, adequate food production in 2050 could be achieved on less land than is currently used, allowing considerable forest regeneration, and reducing land-based GHG emissions to one third of the reference ‘business-as-usual’ case for 2050, a reduction of 7.8 GtCO <sub>2</sub> -eq yr <sup>-1</sup> . Springmann et al. (2016b) <sup>[[#fn:r873|873]]</sup> recently estimated similar emissions reduction potential of 8 GtCO <sub>2</sub> -eq yr <sup>–1</sup> from a vegan diet without animal-sourced foods. This defines the upper bound of the technical mitigation potential of demand side measures.

Herrero et al. (2016a) <sup>[[#fn:r874|874]]</sup> reviewed available options, with a specific focus on livestock products, assessing technical mitigation potential across a range of scenarios, including ‘no animal products’, ‘no meat’, ‘no ruminant meat’, and ‘healthy diet’ (reduced meat consumption). With regard to ‘credible low-meat diets’, where reduction in animal protein intake was compensated by higher intake of pulses, emissions reductions by 2050 could be in the4.3–6.4GtCO <sub>2</sub> -eqyr <sup>-1</sup> , compared to a business-as-usual scenario.

Of this technical potential, 1–2 GtCO <sub>2</sub> -eq yr <sup>–1</sup> come from reductions of mostly non-CO <sub>2</sub> GHG within the farm gate, while the remainder was linked to carbon sequestration on agricultural lands no longer needed for livestock production. When the transition to a low-meat diet reduces the agricultural area required, land is abandoned, and the re-growing vegetation can take up carbon until a new equilibrium is reached. This is known as the land-sparing effect.

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'''Figure 5.12'''

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'''Technical mitigation potential of changing diets by 2050 according to a range of scenarios examined in the literature. Estimates indicate technical potential only and include additional effects of carbon sequestration from land-sparing. Data without error bars are from one study only. All diets need to provide a full complement of nutritional quality, including micronutrients (FAO […]'''
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[[File:450356c96dd4130de6f3dfc759fe9ea2 Figure-5.12-1024x548.jpg]]

Technical mitigation potential of changing diets by 2050 according to a range of scenarios examined in the literature. Estimates indicate technical potential only and include additional effects of carbon sequestration from land-sparing. Data without error bars are from one study only. All diets need to provide a full complement of nutritional quality, including micronutrients (FAO et al. 2018 <sup>[[#fn:r1452|1452]]</sup> ).Vegan: Completely plant-based (Springmann et al. 2016b <sup>[[#fn:r1453|1453]]</sup> ; Stehfest et al. 2009 <sup>[[#fn:r1454|1454]]</sup> ).Vegetarian: Grains, vegetables, fruits, sugars, oils, eggs and dairy, and generally at most one serving per month of meat or seafood (Springmann et al. 2016b <sup>[[#fn:r1455|1455]]</sup> ; Tilman and Clark 2014 <sup>[[#fn:r1456|1456]]</sup> ; Stehfest et al. 2009 <sup>[[#fn:r1457|1457]]</sup> ).Flexitarian: 75% of meat and dairy replaced by cereals and pulses; at least 500 g per day fruits and vegetables; at least 100 g per day of plant-based protein sources; modest amounts of animal-based proteins and limited amounts of red meat (one portion per week), refined sugar (less than 5% of total energy), vegetable oils high in saturated fat, and starchy foods with relatively high glycaemic index (Springmann et al. 2018a <sup>[[#fn:r1458|1458]]</sup> ; Hedenus et al. 2014 <sup>[[#fn:r1459|1459]]</sup> ).Healthy diet: Based on global dietary guidelines for consumption of red meat, sugar, fruits and vegetables, and total energy intake (Springmann et al. 2018a <sup>[[#fn:r1460|1460]]</sup> ; Bajželj et al. 2014 <sup>[[#fn:r1461|1461]]</sup> ).Fair and frugal: Global daily per-capita calorie intake of 2800 kcal/cap/day (11.7 MJ/cap/day), paired with relatively low level of animal products (Smith et al. 2013 <sup>[[#fn:r1462|1462]]</sup> ).Pescetarian: Vegetarian diet that includes seafood (Tilman and Clark 2014 <sup>[[#fn:r1463|1463]]</sup> ).Climate carnivore: 75% of ruminant meat and dairy replaced by other meat (Hedenus et al. 2014 <sup>[[#fn:r1464|1464]]</sup> ).Mediterranean: Vegetables, fruits, grains, sugars, oils, eggs, dairy, seafood, moderate amounts of poultry, pork, lamb and beef (Tilman and Clark 2014 <sup>[[#fn:r1465|1465]]</sup> ).

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Other studies have found similar results for potential mitigation linked to diets. For instance, Smith et al. (2013) analysed a dietary change scenario that assumed a convergence towards a global daily per-capita calorie intake of 2800 kcal per person per day (11.7 MJ per person per day), paired with a relatively low level of animal product supply, estimated technical mitigation potential in the range 0.7–7.3 GtCO <sub>2</sub> -eq yr <sup>–1</sup> for additional variants including low or high-yielding bioenergy, 4.6GtCO <sub>2</sub> -eqyr <sup>–1</sup> if spare land is afforested.

Bajželj et al. (2014) <sup>[[#fn:r875|875]]</sup> developed different scenarios of farm systems change, waste management, and dietary change on GHG emissions coupled to land use. Their dietary scenarios were based on target kilocalorie consumption levels and reductions in animal product consumption. Their scenarios were ‘healthy diet’; healthy diet with 2500 kcal per person per day in 2050; corresponding to technical mitigation potentials in the range 5.8 and 6.4 GtCO <sub>2</sub> -eq yr <sup>-1</sup> .

Hedenus et al. (2014) explored further dietary variants based on the type of livestock product. ‘climate carnivore’, in which 75% of the baseline-consumption of ruminant meat and dairy was replaced

by pork and poultry meat, and ‘flexitarian’, in which 75% of the baseline-consumption of meat and dairy was replaced by pulses and cereal products. Their estimates of technical mitigation potentials by 2050 ranged 3.4–5.2 GtCO <sub>2</sub> -eq yr <sup>-1</sup> , the high end achieved under the flexitarian diet. Finally, Tilman and Clark (2014) used stylised diets as variants that included ‘peseatarian’, ‘Mediterranean’, ‘vegetarian’, compared to a reference diet, and estimated technical mitigation potentials within the farm gate of 1.2–2.3 GtCO <sub>2</sub> -eq yr <sup>-1</sup> , with additional mitigation from carbon sequestration on spared land ranging 1.8–2.4 GtCO <sub>2</sub> -eq yr <sup>-1</sup> .

Studies have defined dietary mitigation potential as, for example, 20 kg per person per week CO <sub>2</sub> -eq for Mediterranean diet, versus 13 kg per person per week CO <sub>2</sub> -eq for vegan (Castañé and Antón 2017 <sup>[[#fn:r876|876]]</sup> ). Rosi et al. (2017) <sup>[[#fn:r877|877]]</sup> developed seven-day diets in Italy for about 150 people defined as omnivore 4.0 ± 1.0; ovo-lacto-veggie 2.6 ± 0.6; and vegan 2.3 ± 0.5 kg CO <sub>2</sub> -eq per capita per day.

Importantly, many more studies that compute the economic and calorie costs of these scenarios are needed. Herrero et al. (2016a) <sup>[[#fn:r878|878]]</sup> estimated that once considerations of economic and calorie costs of their diet-based solutions were included, the technical range of 4.3–6.4 GtCO <sub>2</sub> -eq yr <sup>–1</sup> in 2050 was reduced to 1.8–3.4 GtCO <sub>2</sub> -eq yr <sup>–1</sup> when implementing a GHG tax ranging from 20–100 USD tCO <sub>2</sub> . While caloric costs where low below 20 USD tCO <sub>2</sub> , they ranged from 27–190 kcal per person per day under the higher economic potential, thus indicating possible negative trade-offs with food security.

In summary, demand-side changes in food choices and consumption can help to achieve global GHG mitigation targets ( ''high confidence'' ). Low-carbon diets on average tend to be healthier and have smaller land footprints. By 2050, technical mitigation potential of dietary changes range from 2.7–6.4 GtCO <sub>2</sub> -eq yr <sup>–1</sup> for assessed diets ( ''high confidence'' ). At the same time, the economic potential of such solutions is lower, ranging from 1.8–3.4 GtCO <sub>2</sub> -eq yr <sup>–1</sup> at prices of 20–100 USD tCO <sub>2</sub> , with caloric costs up to 190 kcal per person per day. The feasibility of how to create economically viable transitions to more sustainable and healthy diets that also respect food security requirements needs to be addressed in future research.

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==== 5.5.2.2 Role of dietary preferences ====

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Food preference is an inherently cultural dimension that can ease or hinder transformations to food systems that contribute to climate change mitigation. Consumer choice and dietary preferences are guided by social, cultural, environmental, and traditional factors as well as economic growth. The food consumed by a given group conveys cultural significance about social hierarchy, social systems and human-environment relationships (Herforth and Ahmed 2015).

As suggested by Springmann et al. (2018a), per capita dietary emissions will translate into different realised diets, according to regional contexts including cultural and gendered norms (e.g., among some groups, eating meat is perceived as more masculine (Ruby and Heine 2011). In some cases, women and men have different preferences in terms of food, with women reporting eating healthier food (Imamura et al. 2015 <sup>[[#fn:r879|879]]</sup> ; Kiefer et al. 2005 <sup>[[#fn:r880|880]]</sup> ; Fagerli and Wandel 1999 <sup>[[#fn:r881|881]]</sup> ): these studies found that men tend to eat more meat, while women eat more vegetables, fruits and dairy products (Kanter and Caballero 2012 <sup>[[#fn:r882|882]]</sup> ).

Food preferences can change over time, with the nutrition transition from traditional diets to high-meat, high-sugar, high-saturated fat diets being a clear example of significant changes occurring in a short period of time. Meat consumption per capita consistently responds to income with a saturating trend at high income levels (Sans and Combris 2015 <sup>[[#fn:r883|883]]</sup> ; Vranken et al. 2014 <sup>[[#fn:r884|884]]</sup> ). Some emerging economies have rapidly increased demand for beef, leading to pressure on natural resources (Bowles et al. 2019 <sup>[[#fn:r885|885]]</sup> ). In another example, by reducing beef consumption between 2005 and 2014, Americans avoided approximately 271 million metric tonnes of emissions (CO <sub>2</sub> -eq) (NRDC 2017 <sup>[[#fn:r886|886]]</sup> ). Attending farmers markets or buying directly from local producers has been shown to change worldviews (Kerton and Sinclair 2010 <sup>[[#fn:r887|887]]</sup> ), and food habits towards healthier diets (Pascucci et al. 2011 <sup>[[#fn:r888|888]]</sup> ) can be advanced through active learning (Milestad et al. 2010 <sup>[[#fn:r889|889]]</sup> ).

Regarding the options to reduce meat intake in developed countries, research shows that there is an apparent sympathy of consumers for meat reduction due to environmental impacts (Dagevos and Voordouw 2013 <sup>[[#fn:r890|890]]</sup> ), which has not been exploited. Social factors that influence reducing meat consumption in New Zealand include the need for better education or information dispersal regarding perceived barriers to producing meat-reduced/less meals; ensuring there is sensory or aesthetic appeal; and placing emphasis on human health or nutritional benefits (Tucker 2018 <sup>[[#fn:r891|891]]</sup> ).

Different and complementary strategies can be used in parallel for different consumer’s profiles to facilitate step-by-step changes in the amounts and the sources of protein consumed. In the Netherlands, a nationwide sample of 1083 consumers were used to study their dietary choices toward smaller portions of meat, smaller portions using meat raised in a more sustainable manner, smaller portions and eating more vegetable protein, and meatless meals with or without meat substitutes. Results showed that strategies to change meat eating frequencies and meat portion sizes appeared to overlap and that these strategies can be applied to address consumers in terms of their own preferences (de Boer et al. 2014 <sup>[[#fn:r892|892]]</sup> ).

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==== 5.5.2.3 Uncertainties in demand-side mitigation potential ====

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Both reducing ruminant meat consumption and increasing its efficiency are often identified as the main options to reduce GHG emissions (GHGE) and to lessen pressure on land (Westhoek et al. 2014) (see Section 5.6 for synergies and trade-offs with health and Section 5.7 for discussion of Just Transitions). However, analysing ruminant meat production is highly complex because of the extreme heterogeneity of production systems and due to the numerous products and services associated with ruminants (Gerber et al. 2015 <sup>[[#fn:r893|893]]</sup> ). See Supplementary Material Section SM5.5 for further discussion of uncertainties in estimates of livestock mitigation technical potential. Further, current market mechanisms are regarded as insufficient to decrease consumption or increase efficiency, and governmental intervention is often suggested to encourage mitigation in both the supply-side and demand-side of the food system (Section 5.7) (Wirsenius et al. 2011 <sup>[[#fn:r894|894]]</sup> ; Henderson et al. 2018 <sup>[[#fn:r895|895]]</sup> ).

Minimising GHG emissions through mathematical programming with near-minimal acceptability constraints can be understood as a reference or technical potential for mitigation through diet shifts. In this context (Macdiarmid et al. 2012 <sup>[[#fn:r896|896]]</sup> ) found up to 36% reduction in emissions in UK with similar diet costs applying fixed lifecycle analyses (LCA) carbon footprints (i.e., no rebound effects considered). Westhoek et al. (2014) <sup>[[#fn:r897|897]]</sup> found 25–40% in emissions by halving meat, dairy and egg intake in the EU, applying standard IPCC fixed emission intensity factors. Uncertainty about the consequences of on-the-ground implementation of policies towards low ruminant meat consumption in the food system and their externalities remain noteworthy.

Often, all emissions are allocated only to human edible meat and the boundaries are set only within the farm gate (Henderson et al. 2018 <sup>[[#fn:r898|898]]</sup> ; Gerber et al. 2013 <sup>[[#fn:r899|899]]</sup> ). However, less than 50% of slaughtered cattle weight is human edible meat, and 1–10% of the mass is lost or incinerated, depending on specified risk materials legislation. The remaining mass provide inputs to multiple industries, for example clothing, furniture, vehicle coating materials, biofuel, gelatine, soap, cosmetics, chemical and pharmaceutical industrial supplies, pet feed ingredients and fertilisers (Marti et al. 2011 <sup>[[#fn:r900|900]]</sup> ; Mogensen et al. 2016 <sup>[[#fn:r901|901]]</sup> ; Sousa et al. 2017 <sup>[[#fn:r902|902]]</sup> ). This makes ruminant meat production one of the most complex problems for LCA in the food system (Place and Mitloehner 2012 <sup>[[#fn:r903|903]]</sup> ; de Boer et al. 2011 <sup>[[#fn:r904|904]]</sup> ). There are only a few examples taking into account slaughter by-products (Mogensen et al. 2016 <sup>[[#fn:r905|905]]</sup> ).

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==== 5.5.2.4 Insect-based diets ====

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Edible insects are, in general, rich in protein, fat, and energy and can be a significant source of vitamins and minerals (Rumpold and Schlüter 2015 <sup>[[#fn:r906|906]]</sup> ). Approximately 1900 insect species are eaten worldwide, mainly in developing countries (van Huis 2013 <sup>[[#fn:r907|907]]</sup> ). The development of safe rearing and effective processing methods are mandatory for utilisation of insects in food and feed. Some insect species can be grown on organic side streams, reducing environmental contamination and transforming waste into high-protein feed. Insects are principally considered as meat substitutes, but worldwide meat substitute consumption is still very low, principally due to differences in food culture, and will require transition phases such as powdered forms (Megido et al. 2016 <sup>[[#fn:r908|908]]</sup> and Smetana et al. 2015 <sup>[[#fn:r909|909]]</sup> ). Wider consumer acceptability will relate to pricing, perceived environmental benefits, and the development of tasty insect-derived protein products (van Huis et al. 2015 <sup>[[#fn:r910|910]]</sup> ; van Huis 2013 <sup>[[#fn:r911|911]]</sup> ). Clearly, increasing the share of insect-derived protein has the potential to reduce GHG emissions otherwise associated with livestock production. However, no study to date has quantified such potential.

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==== 5.5.2.5 Food loss and waste, food security, and land use ====

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Food loss and waste impacts food security by reducing global and local food availability, limiting food access due to an increase in food prices and a decrease of producer income, affecting future food production due to the unstainable use of natural resources (HLPE 2014 <sup>[[#fn:r912|912]]</sup> ). Food loss is defined as the reduction of edible food during production, postharvest, and processing, whereas food discarded by consumers is considered as food waste (FAO 2011b <sup>[[#fn:r913|913]]</sup> ). Combined food loss and waste amount to 25–30% of total food produced ( ''medium confidence'' ). During 2010–2016, global food loss and waste equalled 8–10% of total GHG emissions ( ''medium confidence'' ); and cost about 1 trillion USD per year ( ''low confidence'' ) (FAO 2014b <sup>[[#fn:r914|914]]</sup> ).

A large share of produced food is lost in developing countries due to poor infrastructure, while a large share of produced food is wasted in developed countries (Godfray et al. 2010 <sup>[[#fn:r915|915]]</sup> ). Changing consumer behaviour to reduce per capita over-consumption offers substantial potential to improve food security by avoiding related health burdens (Alexander et al. 2017 <sup>[[#fn:r916|916]]</sup> ; Smith 2013 <sup>[[#fn:r917|917]]</sup> ) and reduce emissions associated with the extra food (Godfray et al. 2010 <sup>[[#fn:r918|918]]</sup> ). In 2007, around 20% of the food produced went to waste in Europe and North America, while around 30% of the food produced was lost in Sub-Saharan Africa (FAO 2011b <sup>[[#fn:r919|919]]</sup> ). During the last 50 years, the global food loss and waste increased from around 540 Mt in 1961 to 1630 Mt in 2011 (Porter et al. 2016 <sup>[[#fn:r920|920]]</sup> ).

In 2011, food loss and waste resulted in about 8–10% of total anthropogenic GHG emissions. The mitigation potential of reduced food loss and waste from a full life-cycle perspective, for example, considering both food supply chain activities and land-use change, was estimated as 4.4 GtCO <sub>2</sub> -eq yr <sup>–1</sup> (FAO 2015a, 2013b <sup>[[#fn:r921|921]]</sup> ). At a global scale, loss and waste of milk, poultry meat, pig meat, sheep meat, and potatoes are associated with 3% of the global agricultural N <sub>2</sub> O emissions (more than 200 Gg N <sub>2</sub> O-N yr–1 or 0.06 GtCO <sub>2</sub> -eq yr <sup>–1</sup> ) in 2009 (Reay et al. 2012 <sup>[[#fn:r922|922]]</sup> ). For the USA, 35% of energy use, 34% of blue water use, 34% of GHG emissions, 31% of land use, and 35% of fertiliser use related to an individual’s food-related resource consumption were accounted for as food waste and loss in 2010 (Birney et al. 2017 <sup>[[#fn:r923|923]]</sup> ).

Similar to food waste, over-consumption (defined as food consumption in excess of nutrient requirements), leads to GHG emissions (Alexander et al. 2017 <sup>[[#fn:r924|924]]</sup> ). In Australia for example, over-consumption accounts for about 33% GHGs associated with food (Hadjikakou 2017 <sup>[[#fn:r925|925]]</sup> ). In addition to GHG emissions, over-consumption can also lead to severe health conditions such as obesity or diabetes. Over-eating was found to be at least as large a contributor to food system losses (Alexander et al. 2017 <sup>[[#fn:r926|926]]</sup> ). Similarly, food system losses associated with consuming resource-intensive animal-based products instead of nutritionally comparable plant-based alternatives are defined as ‘opportunity food losses’. These were estimated to be 96, 90, 75, 50, and 40% for beef, pork, dairy, poultry, and eggs, respectively, in the USA (Shepon et al. 2018 <sup>[[#fn:r927|927]]</sup> ).

Avoiding food loss and waste will contribute to reducing emissions from the agriculture sector. By 2050, agricultural GHG emissions associated with production of food that might be wasted may increase to 1.9–2.5 GtCO <sub>2</sub> -eq yr <sup>–1</sup> (Hiç et al. 2016 <sup>[[#fn:r928|928]]</sup> ). When land-use change for agriculture expansion is also considered, halving food loss and waste reduces the global need for cropland area by around 14% and GHG emissions from agriculture and land-use change by 22–28% (4.5 GtCO <sub>2</sub> -eq yr <sup>–1</sup> ) compared to the baseline scenarios by 2050 (Bajželj et al. 2014 <sup>[[#fn:r929|929]]</sup> ). The GHG emissions mitigation potential of food loss and waste reduction would further increase when lifecycle analysis accounts for emissions throughout food loss and waste through all food system activities.

Reducing food loss and waste to zero might not be feasible. Therefore, appropriate options for the prevention and management of food waste can be deployed to reduce food loss and waste and to minimise its environmental consequences. Papargyropoulou et al. (2014 <sup>[[#fn:r930|930]]</sup> ) proposed the Three Rs (i.e., reduction, recovery and recycle) options to prevent and manage food loss and waste. A wide range of approaches across the food supply chain is available to reduce food loss and waste, consisting of technical and non-technical solutions (Lipinski et al. 2013 <sup>[[#fn:r931|931]]</sup> ). However, technical solutions (e.g., improved harvesting techniques, on-farm storage, infrastructure, packaging to keep food fresher for longer, etc.) include additional costs (Rosegrant et al. 2015 <sup>[[#fn:r932|932]]</sup> ) and may have impacts on local environments (FAO 2018b <sup>[[#fn:r933|933]]</sup> ). Additionally, all parts of food supply chains need to become efficient to achieve the full reduction potential of food loss and waste (Lipinski et al. 2013 <sup>[[#fn:r934|934]]</sup> ).

Together with technical solutions, approaches (i.e., non-technical solutions) to changes in behaviours and attitudes of a wide range of stakeholders across the food system will play an important role in reducing food loss and waste. Food loss and waste can be recovered by distributing food surplus to groups affected by food poverty or converting food waste to animal feed (Vandermeersch et al. 2014 <sup>[[#fn:r935|935]]</sup> ). Unavoidable food waste can also be recycled to produce energy based on biological, thermal and thermochemical technologies (Pham et al. 2015 <sup>[[#fn:r936|936]]</sup> ). Additionally, strategies for reducing food loss and waste also need to consider gender dynamics with participation of females throughout the food supply chain (FAO 2018f <sup>[[#fn:r937|937]]</sup> ).

In summary, reduction of food loss and waste can be considered as a climate change mitigation measure that provides synergies with food security and land use ( ''robust evidence, medium agreement'' ). Reducing food loss and waste reduces agricultural GHG emissions and the need for agricultural expansion for producing excess food. Technical options for reduction of food loss and waste include improved harvesting techniques, on-farm storage, infrastructure, and packaging. However, the beneficial effects of reducing food loss and waste will vary between producers and consumers, and across regions. Causes of food loss (e.g., lack of refrigeration) and waste (e.g., behaviour) differ substantially in developed and developing countries ( ''robust evidence, medium agreement'' ). Additionally, food loss and waste cannot be avoided completely.

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==== 5.5.2.6 Shortening supply chains ====

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Encouraging consumption of locally produced food and enhancing efficiency of food processing and transportation can, in some cases, minimise food loss, contribute to food security, and reduce GHG emissions associated with energy consumption and food loss. For example, Michalský and Hooda (2015) <sup>[[#fn:r938|938]]</sup> , through a quantitative assessment of GHG emissions of selected fruits and vegetables in the UK, reported that increased local production offers considerable emissions savings. They also highlighted that when imports are necessary, importing from Europe instead of the Global South can contribute to considerable GHG emissions savings. Similar results were found by Audsley et al. (2010) <sup>[[#fn:r939|939]]</sup> , with exceptions for some foods, such as tomatoes, peppers or sheep and goat meat. Similarly, a study in India shows that long and fragmented supply chains, which lead to disrupted price signals, unequal power relations perverse incentives and long transport time, could be a key barrier to reducing post-harvest losses (CIPHET 2007 <sup>[[#fn:r940|940]]</sup> ).

In other cases, environmental benefits associated with local food can be offset by inefficient production systems with high emission intensity and resource needs, such as water, due to local conditions. For example, vegetables produced in open fields can have much lower GHG emissions than locally produced vegetables from heated greenhouses (Theurl et al. 2014 <sup>[[#fn:r941|941]]</sup> ). Whether locally grown food has a lower carbon footprint depends on the on-farm emissions intensity as well as the transport emissions. In some cases, imported food may have a lower carbon footprint than locally grown food because some distant countries can produce food at much lower emissions intensity. For example, Avetisyan et al. (2014) <sup>[[#fn:r942|942]]</sup> reported that regional variation of emission intensities associated with production of ruminant products have large implications for emissions associated with local food. They showed that consumption of local livestock products can reduce emissions due to short supply chains in countries with low emission intensities; however, this might not be the case in countries with high emission intensities.

In addition to improving emission intensity, efficient distribution systems for local food are needed for lowering carbon footprints (Newman et al. 2013 <sup>[[#fn:r943|943]]</sup> ). Emissions associated with food transport depend on the mode of transport, for example, emissions are lower for rail rather than truck (Brodt et al. 2013 <sup>[[#fn:r944|944]]</sup> ). Tobarra et al. (2018) <sup>[[#fn:r945|945]]</sup> reported that emissions saving from local food may vary across seasons and regions of import. They highlighted that, in Spain, local production of fruits and vegetables can reduce emissions associated with imports from Africa but imports from France and Portugal can save emissions in comparison to production in Spain. Additionally, local production of seasonal products in Spain reduces emissions, while imports of out-of-season products can save emissions rather than producing them locally.

In summary, consuming locally grown foods can reduce GHG emissions, if they are grown efficiently ( ''high confidence'' ). The emissions reduction potential varies by region and season. Whether food with shorter supply chains has a lower carbon footprint depends on both the on-farm emissions intensity as well as the transport emissions. In some cases, imported food may have a lower carbon footprint because some distant agricultural regions can produce food at lower emissions intensities.

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