Editing IPCC:AR6/WGIII/Chapter-12 (section)

==== 12.4.2.2 GHG Intensities of Food Commodities ====

<div id="h3-6-siblings" class="h3-siblings"></div>

There is high variability in the GHG emissions of different food products and production systems (Figure 12.6). GHG emissions intensities – measured using attributional lifecycle assessment, considering the full supply chain, expressed as CO 2 -eq per kg of product or per kg of protein – are generally highest for ruminant meat, cheese, and certain crustacean species (e.g., farmed shrimp and prawns, trawled lobster) ( [[#Nijdam--2012|Nijdam et al. 2012]] ; [[#Clark--2017|Clark and Tilman 2017]] ; [[#Clune--2017|Clune et al. 2017]] ; [[#Hilborn--2018|Hilborn et al. 2018]] ; Poore and Nemecek 2018) ( ''robust evidence, high agreement'' ) ''.'' Generally, beef from dairy systems has a lower footprint (8–23 kgCO 2 -eq per 100 g protein than beef from beef herds (17–94 kgCO 2 -eq per 100 g protein (Figure 12.6, re-calculated from Poore and Nemecek (2018) using AR6 GWPs based on a 100year horizon) ( ''medium evidence'' , ''high agreement'' ). The wide variation in emissions from beef reflects differences in production systems, which range from intensive feedlots with stock raised largely on grains through to rangeland and transhumance production systems. Dairy systems are generally more intensive production systems, with higher digestibility feed than beef systems. Further, emissions from dairy systems are shared between milk and meat, which brings GHG footprints of beef from dairy herds closer to those of meat from monogastric animals, with emissions intensities of pork (4.4–13 kgCO 2 -eq per 100 g protein) and poultry meat (2.3–11 kgCO 2 -eq per 100 g protein) (Poore and Nemecek 2018).

<div id="_idContainer107" class="_idGenObjectStyleOverride-1"></div>

[[File:67e8f8e10f0276f12a17395f54ec004f IPCC_AR6_WGIII_Figure_12_6.png]]

'''Figure 12.6 | Ranges of GHG intensities [kgCO''' 2 '''-eq per 100 g protein,''' '''10–90''' th '''percentile] in protein-rich foods, quantified via a meta-analysis of attributional lifecycle assessment studies using economic allocation.''' Aggregation of CO 2 , CH 4 , and N 2 O emissions in Poore and Nemecek (2018) updated to use AR6 100-year GWP. Data for capture fish, crustaceans, and cephalopods from [[#Parker--2018|Parker et al. (2018)]] , with post-farm data from Poore and Nemecek (2018), where the ranges represent differences across species groups. CH 4 emissions include emissions from manure management, enteric fermentation, and flooded rice only. a Grains are not generally classed as protein-rich, but they provide about 41% of global protein intake. Here grains are a weighted average of wheat, maize, oats, and rice by global protein intake. b Conversion of annual to perennial crops can lead to carbon sequestration in woody biomass and soil, shown as negative emissions intensity. Source: data from Poore and Nemecek (2018); [[#Parker--2018|Parker et al. (2018)]] .

Emissions intensities for farmed fish ranged from 2.4–11 kgCO 2 -eq per 100 g protein (Poore and Nemecek 2018). For Norwegian seafood, large differences have been found ranging from 1.1 kgCO 2 -eq kg –1 edible product for herring to more than 8 kgCO 2 -eq kg –1 edible product for salmon shipped by road and ferry from Oslo to Paris ( [[#Winther--2020|Winther et al. 2020]] ). For capture fish, large differences in emissions have been found, ranging from 0.2–7.9 kgCO 2 -eq kg –1 landed fish ( [[#Parker--2018|Parker et al. 2018]] ), although an environmental comparison of capture fish to farmed foods should include other indicators such as overfishing. Plant-based foods generally have lower GHG emissions (–2.2 to +4.5 kgCO 2 -eq per 100 g protein) than farmed animal-based foods ( [[#Nijdam--2012|Nijdam et al. 2012]] ; [[#Clark--2017|Clark and Tilman 2017]] ; [[#Clune--2017|Clune et al. 2017]] ; [[#Hilborn--2018|Hilborn et al. 2018]] ; Poore and Nemecek 2018) ( ''robust evidence, high agreement'' ). Several plant-based foods are associated with emissions from land use change, for example, palm oil, soy and coffee (Poore and Nemecek 2018), although emissions intensities are context specific ( [[#Meijaard--2020|Meijaard et al. 2020]] ) and for plant-based proteins, GHG footprints per serving remain lower than those of animal source proteins ( [[#Kim--2019|Kim et al. 2019]] ) ''.''

In traditional production systems, especially in developing countries, livestock serve multiple functions, providing draught power, fertiliser, investment and social status, besides constituting an important source of nutrients ( [[#Weiler--2014|Weiler et al. 2014]] ). In landscapes dominated by forests or cropland, semi-natural pastures grazed by ruminants provide heterogeneity that supports biodiversity ( [[#Röös--2016|Röös et al. 2016]] ). Grazing on marginal land and the use of crop residues and food waste can provide human-edible food with lower demands for cropland ( [[#Röös--2016|Röös et al. 2016]] ; [[#Van%20Zanten--2018|Van Zanten et al. 2018]] ; Van Hal et al. 2019). Animal protein requires more land than vegetable protein, so switching consumption from animal to vegetable proteins could reduce the pressure on land resources and potentially enable additional mitigation through expansion of natural ecosystems, storing carbon while supporting biodiversity, or reforestation to sequester carbon and enhance wood supply capacity for the production of bio-based products substituting fossil fuels, plastics, cement, etc. ( [[#Schmidinger--2012|Schmidinger and Stehfest 2012]] ; [[#Searchinger--2018b|Searchinger et al. 2018b]] ; [[#Hayek--2021|Hayek et al. 2021]] ). At the same time, alternatives to animal-based meat and other livestock products are being developed (Figure 12.6). Their increasing visibility in supermarkets and catering services, as well as falling production prices, could make meat substitutes competitive in one to two decades ( [[#Gerhardt--2019|Gerhardt et al. 2019]] ). However, uncertainty around their uptake creates uncertainty around their effect on future GHG emissions.

<div id="12.4.2.3" class="h3-container"></div>

<span id="territorial-national-per-capita-ghg-emissions-from-food-systems"></span>