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{{Short description|Impact of farming animals on the environment}}
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The '''environmental impacts of animal agriculture''' vary because of the wide variety of [[Agriculture|agricultural]] practices employed around the world. Despite this, all agricultural practices have been found to have [[environmental impact of agriculture|a variety of effects on the environment]] to some extent. Animal agriculture, in particular [[meat production]], can cause [[pollution]], [[greenhouse gas emissions]], [[biodiversity loss]], disease, and significant [[Land consumption|consumption of land]], food, and water. Meat is obtained through a variety of methods, including [[organic farming]], [[Free range|free-range farming]], [[Intensive animal farming|intensive livestock production]], and [[subsistence agriculture]]. The livestock sector also includes wool, [[Dairy farming#Concerns|egg and dairy production]], the livestock used for [[tillage]], and [[fish farming]].
Animal agriculture is a significant contributor to [[greenhouse gas emissions from agriculture|greenhouse gas emissions]]. Cows, sheep, and other [[ruminant]]s digest their food by [[enteric fermentation]], and their [[Burping|burps]] are the main source of [[methane emissions]] from [[land use, land-use change, and forestry]]. Together with methane and [[nitrous oxide]] from [[manure]], this makes livestock the main source of greenhouse gas emissions from agriculture.<ref name="IPCC Sixth Assessment Report-2022">{{Cite report |url=https://www.ipcc.ch/report/sixth-assessment-report-working-group-3/ |title=Mitigation of Climate Change: Full report |publisher=[[IPCC Sixth Assessment Report]] |year=2022 |at=7.3.2.1 page 771}}</ref> A significant reduction in meat consumption is essential to mitigate climate change, especially as the human population increases by a projected 2.3 billion by the middle of the century.<ref name="Carrington-2018" /><ref name="Eisen-2022">{{Cite journal |last1=Eisen |first1=Michael B. |last2=Brown |first2=Patrick O. |date=2022-02-01 |title=Rapid global phaseout of animal agriculture has the potential to stabilize greenhouse gas levels for 30 years and offset 68 percent of {{CO2}} emissions this century |journal=PLOS Climate |language=en |volume=1 |issue=2 |pages=e0000010 |doi=10.1371/journal.pclm.0000010 |issn=2767-3200 |s2cid=246499803 |doi-access=free}}</ref>
== Consumption and production trends ==
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A 2023 study found that a [[vegan]] diet reduced land use by 75%.<ref name="Carrington-2023">{{cite news |last1=Carrington |first1=Damian |date=20 July 2023 |title=Vegan diet massively cuts environmental damage, study shows |work=[[The Guardian]] |url=https://www.theguardian.com/environment/2023/jul/20/vegan-diet-cuts-environmental-damage-climate-heating-emissions-study |access-date=20 July 2023}}</ref>
Free-range animal production, particularly [[Beef#Environmental impact|beef production]], has also caused tropical [[deforestation]] because it requires land for grazing.<ref name="snmeat">{{cite news |date=5 May 2022 |title=How much does eating meat affect nations' greenhouse gas emissions? |work=Science News |url=https://www.sciencenews.org/article/food-emissions-data-diet-carbon-greenhouse-gas-climate-agriculture |access-date=27 May 2022}}</ref> The livestock sector is also the primary driver of deforestation in [[Deforestation of the Amazon rainforest|the Amazon]], with around 80% of all deforested land being used for cattle farming.<ref>{{cite news |last=Wang |first=George C. |date=April 9, 2017 |title=Go vegan, save the planet |work=[[CNN]] |url=http://www.cnn.com/2017/04/08/opinions/go-vegan-save-the-planet-wang/ |access-date=August 25, 2019}}</ref><ref>{{cite news |last=Liotta |first=Edoardo |date=August 23, 2019 |title=Feeling Sad About the Amazon Fires? Stop Eating Meat |work=[[Vice Media|Vice]] |url=https://www.vice.com/en_in/article/bjwzk4/feeling-sad-about-the-amazon-fires-stop-eating-meat |access-date=August 25, 2019}}</ref> Additionally, 91% of deforested land since 1970 has been used for cattle farming.<ref name="fao">{{cite book |author1=Steinfeld, Henning |url=http://www.fao.org/docrep/010/a0701e/a0701e00.htm |title=Livestock's Long Shadow: Environmental Issues and Options |author2=Gerber, Pierre |author3=Wassenaar, T. D. |author4=Castel, Vincent |publisher=[[Food and Agriculture Organization of the United Nations]] |year=2006 |isbn=978-92-5-105571-7 |access-date=August 19, 2008}}</ref><ref name="worldbank">{{cite book |last=Margulis |first=Sergio |url=http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2004/02/02/000090341_20040202130625/Rendered/PDF/277150PAPER0wbwp0no1022.pdf |title=Causes of Deforestation of the Brazilian Amazon |
=== Water use ===
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Groundwater depletion is a concern in some areas because of sustainability issues (and in some cases, land subsidence and/or [[saltwater intrusion]]).<ref>Konikow, L. W. 2013. Groundwater depletion in the United States (1900-2008). [[United States Geological Survey]]. Scientific Investigations Report 2013-5079. 63 pp.</ref> A particularly important North American example of depletion is the High Plains (Ogallala) Aquifer, which underlies about 174,000 square miles in parts of eight states of the USA and supplies 30 percent of the groundwater withdrawn for irrigation there.<ref>{{Cite web |title=HA 730-C High Plains aquifer. Ground Water Atlas of the United States. Arizona, Colorado, New Mexico, Utah |url=https://pubs.usgs.gov/ha/ha730/ch_c/C-text5.html |access-date=2018-10-13 |website=[[United States Geological Survey]]}}</ref> Some irrigated livestock feed production is not hydrologically sustainable in the long run because of aquifer depletion. [[Rainfed agriculture]], which cannot deplete its water source, produces much of the livestock feed in North America. Corn (maize) is of particular interest, accounting for about 91.8% of the grain fed to US livestock and poultry in 2010.<ref name="USDA2011">USDA. 2011. USDA Agricultural Statistics 2011.</ref>{{rp|table 1–75}} About 14 percent of US corn-for-grain land is irrigated, accounting for about 17% of US corn-for-grain production and 13% of US irrigation water use,<ref>USDA 2010. 2007 Census of agriculture. AC07-SS-1. Farm and ranch irrigation survey (2008). Volume 3, Special Studies. Part 1. (Issued 2009, updated 2010.) 209 pp. + appendices. Tables 1 and 28.</ref><ref name="USDA2009">USDA. 2009. 2007 Census of Agriculture. United States Summary and State Data. Vol. 1. Geographic Area Series. Part 51. AC-07-A-51. 639 pp. + appendices. Table 1.</ref> but only about 40% of US corn grain is fed to US livestock and poultry.<ref name="USDA2011" />{{rp|table 1–38}} Irrigation accounts for about 37% of US withdrawn freshwater use, and groundwater provides about 42% of US irrigation water.<ref name="Kenny2009" /> Irrigation water applied in the production of livestock feed and forage has been estimated to account for about 9 percent of withdrawn freshwater use in the United States.<ref>Zering, K. D., T. J. Centner, D. Meyer, G. L. Newton, J. M. Sweeten and S. Woodruff.2012. Water and land issues associated with animal agriculture: a U.S. perspective. CAST Issue Paper No. 50. Council for Agricultural Science and Technology, Ames, Iowa. 24 pp.</ref>
Almost one-third of the water used in the western United States goes to crops that feed cattle.<ref>{{Cite journal |last1=Richter |first1=Brian D. |last2=Bartak |first2=Dominique |last3=Caldwell |first3=Peter |last4=Davis |first4=Kyle Frankel |last5=Debaere |first5=Peter |last6=Hoekstra |first6=Arjen Y. |last7=Li |first7=Tianshu |last8=Marston |first8=Landon |last9=McManamay |first9=Ryan |last10=Mekonnen |first10=Mesfin M. |last11=Ruddell |first11=Benjamin L. |date=2020-03-02 |title=Water scarcity and fish imperilment driven by beef production |url=http://www.nature.com/articles/s41893-020-0483-z |journal=Nature Sustainability |language=en |volume=3 |issue=4 |pages=319–328 |doi=10.1038/s41893-020-0483-z |bibcode=2020NatSu...3..319R |issn=2398-9629 |s2cid=211730442}}</ref> This is despite the claim that withdrawn surface water and groundwater used for crop [[irrigation]] in the US exceeds that for livestock by about a ratio of 60:1.<ref name="Kenny2009">Kenny, J. F. et al. 2009. [http://pubs.usgs.gov/circ/1344/pdf/c1344.pdf Estimated use of water in the United States in 2005], ''[[United States Geological Survey|US Geological Survey]] Circular'' 1344. 52 pp.</ref> This excessive use of river water distresses ecosystems and communities, and drives scores of species of fish closer to [[extinction]] during times of drought.<ref>{{cite news |last=Borunda |first=Alejandra |date=March 2, 2020 |title=How beef eaters in cities are draining rivers in the American West |work=[[National Geographic]] |url=https://www.nationalgeographic.com/science/2020/03/burger-water-shortages-colorado-river-western-us/ |archive-url=https://web.archive.org/web/20200303025435/https://www.nationalgeographic.com/science/2020/03/burger-water-shortages-colorado-river-western-us/ |url-status=dead |archive-date=March 3, 2020 |access-date=April 27, 2020}}</ref>
A 2023 study found that a [[vegan]] diet reduced water usage by 54%.<ref name="Carrington-2023" />
A study in 2019 focused on linkages between water usage and animal agricultural practices in China.<ref name="Xiao-2019">{{Cite journal |last1=Xiao |first1=Zhengyan |last2=Yao |first2=Meiqin |last3=Tang |first3=Xiaotong |last4=Sun |first4=Luxi |date=2019-01-01 |title=Identifying critical supply chains: An input-output analysis for Food-Energy-Water Nexus in China |url=http://dx.doi.org/10.1016/j.ecolmodel.2018.11.006 |journal=Ecological Modelling |volume=392 |pages=31–37 |doi=10.1016/j.ecolmodel.2018.11.006 |bibcode=2019EcMod.392...31X |s2cid=92222220 |issn=0304-3800}}</ref> The results of the study showed that water resources were being used primarily for animal agriculture; the highest categories were animal husbandry, agriculture, slaughtering and processing of meat, fisheries, and other foods. Together they accounted for the consumption of over 2400 billion m<sup>3</sup> embodied water, roughly equating to 40% of total embodied{{clarify|date=May 2023}} water by the whole system.<ref name="Xiao-2019" /> This means that more than one-third of China's entire water consumption is being used for food processing purposes, and mostly for animal agricultural practices.
{| class="wikitable sortable" style="text-align:right"
|+Estimated water requirements for various foods<ref>{{Cite web |last=Fabrique [merken |first=design & interactie |title=Water footprint of crop and animal products: a comparison |url=https://www.waterfootprint.org/time-for-action/what-can-consumers-do/#cropvanimal/ |access-date=2023-01-13 |website=waterfootprint.org |language=en}}</ref>
!rowspan=2|Foodstuff
!colspan=4|Litres per
|-
!kilocalorie
!gram of<br>protein
!kg of<br>foodstuff
!gram of<br>fat
|-
!Sugar crops
|0.69
|
|197
|
|-
|1.34
|26
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|154
|-
|0.47
|31
Line 105 ⟶ 106:
|226
|-
|2.09
|180
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|348
|-
|0.51
|21
Line 117 ⟶ 118:
|112
|-
|0.81
|16
Line 123 ⟶ 124:
|11
|-
|1.19
|19
Line 129 ⟶ 130:
|180
|-
|3.63
|139
Line 135 ⟶ 136:
|47
|-
|1.82
|31
Line 141 ⟶ 142:
|33
|-
|2.29
|29
Line 147 ⟶ 148:
|33
|-
|3.00
|34
Line 153 ⟶ 154:
|43
|-
|0.72
|
|5553
|6.4
|-
|2.15
|57
Line 165 ⟶ 166:
|23
|-
|4.25
|63
Line 171 ⟶ 172:
|54
|-
|10.19
|112
Line 183 ⟶ 184:
A 2023 study found that a [[vegan]] diet reduced water pollution by 75%.<ref name="Carrington-2023" />[[File:River algae Sichuan.jpg|thumb|A green algae bloom has been observed in Sichuan, China. In normal conditions, river water is transparent, but algae blooms result in green algae covering the surface. This prevents other plants at the bottom of the river from getting sunlight, causing them to lose their ability to photosynthesise. Oxygen levels in rivers fall when there is no other vegetation, resulting in the death of other species.]]Effective use of [[fertilizer]] is crucial to accelerate the growth of animal feed production, which in turn increases the amount of feed available for livestock.<ref name="Zhou 2010 80–102">{{Cite journal |last1=Zhou |first1=Yuan |last2=Yang |first2=Hong |last3=Mosler |first3=Hans-Joachim |last4=Abbaspour |first4=Karim C. |date=2010 |title=Factors affecting farmers' decisions on fertilizer use: A case study for the Chaobai watershed in Northern China |url=https://www.jstor.org/stable/26167133 |journal=Consilience |issue=4 |pages=80–102 |jstor=26167133 |issn=1948-3074}}</ref> However, excess fertilizer can enter water bodies via runoff after rainfall, resulting in [[eutrophication]].<ref>{{Cite journal |last1=HERNÁNDEZ |first1=DANIEL L. |last2=VALLANO |first2=DENA M. |last3=ZAVALETA |first3=ERIKA S. |last4=TZANKOVA |first4=ZDRAVKA |last5=PASARI |first5=JAE R. |last6=WEISS |first6=STUART |last7=SELMANTS |first7=PAUL C. |last8=MOROZUMI |first8=CORINNE |date=2016 |title=Nitrogen Pollution Is Linked to US Listed Species Declines |journal=BioScience |volume=66 |issue=3 |pages=213–222 |doi=10.1093/biosci/biw003 |jstor=90007566 |issn=0006-3568|doi-access=free }}</ref> The addition of nitrogen and phosphorus can cause the rapid growth of algae, also known as an [[Algal bloom|algae bloom]]. The reduction of oxygen and nutrients in the water caused by the growth of algae ultimately leads to the death of other species in the [[ecosystem]]. This ecological harm has consequences not only for the native animals in the affected water body but also for the water supply for people.<ref name="Zhou 2010 80–102" />
To dispose of animal waste and other pollutants, animal production farms often spray manure (often contaminated with potentially toxic bacteria) onto empty fields, called "spray-fields", via sprinkler systems. The toxins within these spray-fields oftentimes run into creeks, ponds, lakes, and other bodies of water, contaminating bodies of water. This process has also led to the contamination of drinking water reserves, harming the environment and citizens alike.<ref>{{Cite web |last=Berger |first=Jamie |date=2022-04-01 |title=How Black North Carolinians pay the price for the
=== Air pollution ===
{{Bar chart|title=Mean [[Acid rain|acidifying emissions]] (air pollution) of different foods per 100g of protein<ref name="Nemecek 987–992"
Animal agriculture is a cause of harmful [[Particulates|particulate matter]] pollution in the atmosphere. This type of production chain produces byproducts; endotoxin, hydrogen sulfide, ammonia, and particulate matter (PM), such as dust,<ref>{{cite journal |last1=Merchant |first1=James A. |last2=Naleway |first2=Allison L. |last3=Svendsen |first3=Erik R. |last4=Kelly |first4=Kevin M. |last5=Burmeister |first5=Leon F. |last6=Stromquist |first6=Ann M. |last7=Taylor |first7=Craig D. |last8=Thorne |first8=Peter S. |last9=Reynolds |first9=Stephen J. |last10=Sanderson |first10=Wayne T. |last11=Chrischilles |first11=Elizabeth A. |year=2005 |title=Asthma and Farm Exposures in a Cohort of Rural Iowa Children |journal=Environmental Health Perspectives |volume=113 |issue=3 |pages=350–356 |doi=10.1289/ehp.7240 |pmc=1253764 |pmid=15743727}}</ref><ref>{{Cite web |last=Borrell |first=Brendan |date=December 3, 2018 |title=In California's Fertile Valley, a Bumper Crop of Air Pollution |url=https://undark.org/article/air-pollution-california/ |access-date=2019-09-27 |website=Undark |language=en-US}}</ref> all of which can negatively impact human respiratory health.<ref>{{cite journal |last1=Viegas |first1=S. |last2=Faísca |first2=V. M. |last3=Dias |first3=H. |last4=Clérigo |first4=A. |last5=Carolino |first5=E. |last6=Viegas |first6=C. |year=2013 |title=Occupational Exposure to Poultry Dust and Effects on the Respiratory System in Workers |journal=Journal of Toxicology and Environmental Health, Part A |volume=76 |issue=4–5 |pages=230–239 |doi=10.1080/15287394.2013.757199 |pmid=23514065 |bibcode=2013JTEHA..76..230V |s2cid=22558834}}</ref> Furthermore, [[Methane emissions|methane]] and {{CO2}}—the primary greenhouse gas emissions associated with meat production—have also been associated with respiratory diseases like asthma, bronchitis, and COPD.<ref>{{cite journal |last1=George |first1=Maureen |last2=Bruzzese |first2=Jean-Marie |last3=Matura |first3=Lea Ann |year=2017 |title=Climate Change Effects on Respiratory Health: Implications for Nursing |journal=Journal of Nursing Scholarship |volume=49 |issue=6 |pages=644–652 |doi=10.1111/jnu.12330 |pmid=28806469 |doi-access=free}}</ref>
A study found that [[concentrated animal feeding operation]]s (CAFOs) could increase perceived asthma-like symptoms for residents within 500 meters.<ref>{{cite journal |last1=Radon |first1=Katja |last2=Schulze |first2=Anja |last3=Ehrenstein |first3=Vera |last4=Van Strien |first4=Rob T. |last5=Praml |first5=Georg |last6=Nowak |first6=Dennis |year=2007 |title=Environmental Exposure to Confined Animal Feeding Operations and Respiratory Health of Neighboring Residents |journal=Epidemiology |volume=18 |issue=3 |pages=300–308 |doi=10.1097/01.ede.0000259966.62137.84 |pmid=17435437 |s2cid=15905956|doi-access=free }}</ref> Concentrated hog feeding operations release air pollutants from confinement buildings, manure holding pits, and land application of waste. Air pollutants from these operations have caused acute physical symptoms, such as respiratory illnesses, wheezing, increased breath rate, and irritation of the eyes and nose.<ref>{{cite journal |last1=Schinasi |first1=Leah |last2=Horton |first2=Rachel Avery |last3=Guidry |first3=Virginia T. |last4=Wing |first4=Steve |last5=Marshall |first5=Stephen W. |last6=Morland |first6=Kimberly B. |year=2011 |title=Air Pollution, Lung Function, and Physical Symptoms in Communities Near Concentrated Swine Feeding Operations |journal=Epidemiology |volume=22 |issue=2 |pages=208–215 |doi=10.1097/ede.0b013e3182093c8b |pmc=5800517 |pmid=21228696}}</ref><ref>{{cite journal |last1=Mirabelli |first1=M. C. |last2=Wing |first2=S. |last3=Marshall |first3=S. W. |last4=Wilcosky |first4=T. C. |year=2006 |title=Asthma Symptoms Among Adolescents Who Attend Public Schools That Are Located Near Confined Swine Feeding Operations |journal=Pediatrics |volume=118 |issue=1 |pages=e66–e75 |doi=10.1542/peds.2005-2812 |pmc=4517575 |pmid=16818539}}</ref><ref>{{cite journal |last1=Pavilonis |first1=Brian T. |last2=Sanderson |first2=Wayne T. |last3=Merchant |first3=James A. |year=2013 |title=Relative exposure to swine animal feeding operations and childhood asthma prevalence in an agricultural cohort |journal=Environmental Research |volume=122 |pages=74–80 |bibcode=2013ER....122...74P |doi=10.1016/j.envres.2012.12.008 |pmc=3980580 |pmid=23332647}}</ref> That prolonged exposure to airborne animal particulate, such as swine dust, induces a large influx of inflammatory cells into the airways.<ref>{{cite journal |last1=Müller-Suur |first1=C. |last2=Larsson |first2=K. |last3=Malmberg |first3=P. |last4=Larsson |first4=P.H. |year=1997 |title=Increased number of activated lymphocytes in human lung following swine dust inhalation |journal=European Respiratory Journal |volume=10 |issue=2 |pages=376–380 |doi=10.1183/09031936.97.10020376 |pmid=9042635 |doi-access=free}}</ref> Those in close proximity to CAFOs could be exposed to elevated levels of these byproducts, which may lead to poor health and respiratory outcomes.<ref>{{Cite journal |last=Carrie |first=Hribar |date=2010 |title=Understanding Concentrated Animal Feeding Operations and Their Impact on Communities |url=https://www.cdc.gov/nceh/ehs/docs/understanding_cafos_nalboh.pdf |journal=2010 National Association of Local Boards of Health |via=Centres for Disease Control and Prevention}}</ref> Additionally, since CAFOs tend to be located in primarily rural and low-income communities, low-income people are disproportionately affected by these environmental health consequences. [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1637958/]
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=== Energy consumption ===
[[File:Energy efficiency of meat and dairy production, OWID.svg|thumb|400px|Energy efficiency of meat and dairy production]]
An important aspect of energy use in livestock production is the energy consumption that the animals contribute. Feed Conversion Ratio is an animal's ability to convert feed into meat. The Feed Conversion Ratio (FCR) is calculated by taking the energy, protein, or mass input of the feed divided by the output of meat provided by the animal. A lower FCR corresponds with a smaller requirement of feed per meat output, and therefore the animal contributes less GHG emissions. Chickens and pigs usually have a lower FCR compared to ruminants.<ref>{{Cite journal |last1=Röös |first1=Elin |last2=Sundberg |first2=Cecilia |last3=Tidåker |first3=Pernilla |last4=Strid |first4=Ingrid |last5=Hansson |first5=Per-Anders |date=2013-01-01 |title=Can carbon footprint serve as an indicator of the environmental impact of meat production? |journal=Ecological Indicators |volume=24 |pages=573–581 |doi=10.1016/j.ecolind.2012.08.004|bibcode=2013EcInd..24..573R }}</ref>
Intensification and other changes in the livestock industries influence energy use, emissions, and other environmental effects of meat production.<ref>{{cite journal |last1=Capper |first1=J. L. |year=2011 |title=The environmental impact of beef production in the United States: 1977 compared with 2007. |journal=J. Anim. Sci. |volume=89 |issue=12 |pages=4249–4261 |doi=10.2527/jas.2010-3784 |pmid=21803973 |doi-access=free}}</ref>
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=== Greenhouse gas emissions ===
{{
==== Methane and nitrous oxide emissions from cattle ====
The [[Food and Agriculture Organization]] estimates that in 2015 around 7% of global [[greenhouse gas emissions]] (GHG) were due to cattle,{{refn|FAO say that in 2015 livestock production created around 12% of greenhouse gas emissions, some 62% of which is due to cattle, thus 7%.<ref>{{Cite web |title=New FAO report maps pathways towards lower livestock emissions |url=https://www.fao.org/newsroom/detail/new-fao-report-maps-pathways-towards-lower-livestock-emissions/en |access-date=2024-03-25 |website=Newsroom}}</ref>|group=note}} but this is uncertain.<ref name=":32">{{Cite web |title=Livestock Don't Contribute 14.5% of Global Greenhouse Gas Emissions |url=https://thebreakthrough.org/issues/food-agriculture-environment/livestock-dont-contribute-14-5-of-global-greenhouse-gas-emissions |access-date=2024-03-25 |website=The Breakthrough Institute}}</ref> Another estimate is 12% of global GHG.<ref name=":4">{{Cite news |date=2 October 2021 |title=Treating beef like coal would make a big dent in greenhouse-gas emissions |url=https://www.economist.com/graphic-detail/2021/10/02/treating-beef-like-coal-would-make-a-big-dent-in-greenhouse-gas-emissions |url-access=subscription |access-date=3 November 2021 |newspaper=The Economist |issn=0013-0613}}</ref> More recently [[Climate TRACE|Climate Trace]] estimates 4.5% directly from cattle in 2022. Reducing [[Methane emissions from livestock|methane emissions]] quickly helps [[Climate change mitigation|limit climate change]].<ref name=":32" />[[File:Carbon_footprint_of_protein_foods.png|thumb|Beef and lamb have the largest carbon footprint of protein-rich foods.]]
{| class="wikitable"
|+Estimates by Climate TRACE<ref>{{Cite web |title=Sectors - Climate TRACE |url=https://climatetrace.org/sectors |access-date=2024-03-27 |website=climatetrace.org |language=en}}</ref>
!Billion tonnes CO2eq (% of total global emissions)
!2022
!2023
|-
|'''Enteric fermentation cattle feedlot'''
|7.95 (1.76)
|
|-
|'''Enteric fermentation cattle pasture'''
|8.55 (1.90)
|
|-
|'''Manure left on pasture cattle'''
|2.91 (0.65)
|
|-
|'''Manure management cattle feedlot'''
|0.70 (0.16)
|
|-
|Total
|20.11 (4.47)
|
|}
[[File:Environmental-impact-of-food-by-life-cycle-stage.png|thumb|Methane production from cows, and land conversion for grazing and animal feed means beef from dedicated beef herds has a very high carbon footprint.]]
[[Gut flora]] in cattle include [[methanogen]]s that [[methanogenesis|produce methane]] as a byproduct of [[enteric fermentation]], which cattle belch out. Additional methane is produced by anaerobic fermentation of manure in [[manure lagoon]]s and other manure storage structures.<ref>US EPA. 2012. Inventory of U.S. greenhouse gase emissions and sinks: 1990–2010. US. Environmental Protection Agency. EPA 430-R-12-001. Section 6.2.</ref> Manure can also release [[nitrous oxide]].<ref>{{Cite journal |last1=Rivera |first1=Julián Esteban |last2=Chará |first2=Julian |date=2021 |title=CH4 and N2O Emissions From Cattle Excreta: A Review of Main Drivers and Mitigation Strategies in Grazing Systems |journal=Frontiers in Sustainable Food Systems |volume=5 |doi=10.3389/fsufs.2021.657936 |issn=2571-581X |doi-access=free}}</ref> Over 20 years [[atmospheric methane]] has 81 times the [[global warming potential]] of the same amount of [[Carbon dioxide in Earth's atmosphere|atmospheric carbon dioxide]].<ref name=":0">{{Citation |title=7.SM.6 Tables of greenhouse gas lifetimes, radiative efficiencies and metrics |date=2021 |page=7SM-24 |url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter_07_Supplementary_Material.pdf |publisher=[[IPCC]]}}.</ref>
As conditions vary a lot<ref name=":1">{{cite journal |last1=Eckard |first1=R. J. |last2=Grainger |first2=C. |last3=de Klein |first3=C.A.M. |year=2010 |title=Options for the abatement of methane and nitrous oxide from ruminant production: A review |journal=Livestock Science |volume=130 |issue=1–3 |pages=47–56 |doi=10.1016/j.livsci.2010.02.010}}</ref> the [[IPCC]] would like these taken into account when estimating [[methane emissions]], in other words countries where cattle are significant should use Tier 3 methods in their national [[Greenhouse gas inventory|greenhouse gas inventories]].<ref>{{Cite journal |last1=Ghassemi Nejad |first1=J. |last2=Ju |first2=M. S. |last3=Jo |first3=J. H. |last4=Oh |first4=K. H. |last5=Lee |first5=Y. S. |last6=Lee |first6=S. D. |last7=Kim |first7=E. J. |last8=Roh |first8=S. |last9=Lee |first9=H. G. |date=2024 |title=Advances in Methane Emission Estimation in Livestock: A Review of Data Collection Methods, Model Development and the Role of AI Technologies |journal=Animals |volume=14 |issue=3 |page=435 |doi=10.3390/ani14030435 |pmc=10854801 |pmid=38338080 |doi-access=free}}</ref> Although well-managed perennial [[Pasture|pastures]] sequester [[Soil carbon|carbon in the soil]], {{As of|2023|lc=y}} [[Life-cycle assessment|life cycle assessments]] are required to fully assess pastoral dairy farms in all environments.<ref name=":2">{{Cite journal |last1=Soder |first1=K. J. |last2=Brito |first2=A. F. |date=2023 |title=Enteric methane emissions in grazing dairy systems |journal=JDS Communications |volume=4 |issue=4 |pages=324–328 |doi=10.3168/jdsc.2022-0297 |pmc=10382831 |pmid=37521055}}</ref>
===Mitigation options===
[[File:Development of per capita meat consumption and gross domestic product (GDP) over time (1990–2017).png|thumb|Per capita meat consumption and [[gross domestic product|GDP]] 1990–2017]]
[[Climate change mitigation|Mitigation options]] for reducing methane emission from livestock include a change in diet, that is consuming less meat and dairy.<ref>{{Cite journal |last1=Poore |first1=J. |last2=Nemecek |first2=T. |date=2018-06-01 |title=Reducing food's environmental impacts through producers and consumers |journal=Science |volume=360 |issue=6392 |pages=987–992 |bibcode=2018Sci...360..987P |doi=10.1126/science.aaq0216 |issn=1095-9203 |pmid=29853680 |s2cid=206664954|doi-access=free }}</ref> A significant reduction in meat consumption will be essential to mitigate climate change, especially as the human population increases by a projected 2.3 billion by the middle of the century.<ref name="Carrington-2018" /> A 2019 report in ''[[The Lancet]]'' recommended that global meat consumption be
In addition to reduced consumption, emissions can also be reduced by changes in practice. One study found that shifting compositions of current feeds, production areas, and informed land restoration could enable greenhouse gas emissions reductions of 34–85% annually (612–1,
Producers can reduce ruminant enteric fermentation using genetic selection,<ref>{{Cite web |url=https://www.genomecanada.ca/en/programs/large-scale-science/past-competitions/strategic-initiatives/bovine-genomics |title=Bovine genomics project at Genome Canada |access-date=2018-11-30 |archive-date=2019-08-10 |archive-url=https://web.archive.org/web/20190810023632/https://www.genomecanada.ca/en/programs/large-scale-science/past-competitions/strategic-initiatives/bovine-genomics |url-status=dead }}</ref><ref>{{cite magazine |title=Canada Is Using Genetics to Make Cows Less Gassy |date=2017-06-09 |magazine=[[Wired (magazine)|Wired]] |archive-url=https://web.archive.org/web/20230524194330/https://www.wired.com/story/canada-is-using-genetics-to-make-cows-less-gassy/ |archive-date=2023-05-24 |url-status=live |url=https://www.wired.com/story/canada-is-using-genetics-to-make-cows-less-gassy/}}</ref> immunization, rumen [[defaunation]], competition of methanogenic archaea with [[acetogens]],<ref>{{cite journal |last1=Joblin |first1=K. N. |year=1999 |title=Ruminal acetogens and their potential to lower ruminant methane emissions |journal=Australian Journal of Agricultural Research |volume=50 |issue=8 |pages=1307 |doi=10.1071/AR99004}}</ref> introduction of [[Methanotroph|methanotrophic bacteria]] into the rumen,<ref>[https://hal.archives-ouvertes.fr/hal-01137190/document The use of direct-fed microbials for mitigation of ruminant methane emissions: a review]</ref><ref>{{cite journal |last1=Parmar |first1=N.R. |last2=Nirmal Kumar |first2=J.I. |last3=Joshi |first3=C.G. |year=2015 |title=Exploring diet-dependent shifts in methanogen and methanotroph diversity in the rumen of Mehsani buffalo by a metagenomics approach |journal=Frontiers in Life Science |volume=8 |issue=4 |pages=371–378 |doi=10.1080/21553769.2015.1063550 |s2cid=89217740}}</ref> diet modification and grazing management, among others.<ref>{{cite journal |last1=Boadi |first1=D |year=2004 |title=Mitigation strategies to reduce enteric methane emissions from dairy cows: Update review |journal=Can. J. Anim. Sci. |volume=84 |issue=3 |pages=319–335 |doi=10.4141/a03-109 |doi-access=free}}</ref><ref>Martin, C. et al. 2010. Methane mitigation in ruminants: from microbe to the farm scale. ''Animal'' 4 : pp 351-365.</ref><ref>{{cite journal |last1=Eckard |first1=R. J. |display-authors=etal |year=2010 |title=Options for the abatement of methane and nitrous oxide from ruminant production: A review |journal=Livestock Science |volume=130 |issue=1–3 |pages=47–56 |doi=10.1016/j.livsci.2010.02.010}}</ref> The principal mitigation strategies identified for reduction of agricultural [[nitrous oxide]] emissions are avoiding over-application of [[nitrogen fertilizers]] and adopting suitable [[manure management]] practices.<ref>{{cite journal |last1=Dalal |first1=R.C. |display-authors=etal |year=2003 |title=Nitrous oxide emission from Australian agricultural lands and mitigation options: a review |journal=[[Australian Journal of Soil Research]] |volume=41 |issue=2 |pages=165–195 |doi=10.1071/sr02064 |s2cid=4498983}}</ref><ref>{{cite journal |last1=Klein |first1=C. A. M. |last2=Ledgard |first2=S. F. |year=2005 |title=Nitrous oxide emissions from New Zealand agriculture – key sources and mitigation strategies |journal=Nutrient Cycling in Agroecosystems |volume=72 |issue=1 |pages=77–85 |doi=10.1007/s10705-004-7357-z |bibcode=2005NCyAg..72...77D |s2cid=42756018}}</ref> Mitigation strategies for reducing carbon dioxide emissions in the livestock sector include adopting more efficient production practices to reduce agricultural pressure for deforestation (such as in Latin America), reducing fossil fuel consumption, and increasing [[carbon sequestration]] [[Soil carbon|in soils]].<ref name="Gerber2013">Gerber, P. J., H. Steinfeld, B. Henderson, A. Mottet, C. Opio, J. Dijkman, A. Falcucci and G. Tempio. 2013. Tackling climate change through livestock - a global assessment of emissions and mitigation opportunities. Food and Agriculture Organization of the United Nations, Rome. 115 pp.</ref>
Methane belching from cattle might be reduced by intensification of farming,<ref>{{Cite journal |last1=Reisinger |first1=Andy |last2=Clark |first2=Harry |last3=Cowie |first3=Annette L. |last4=Emmet-Booth |first4=Jeremy |last5=Gonzalez Fischer |first5=Carlos |last6=Herrero |first6=Mario |last7=Howden |first7=Mark |last8=Leahy |first8=Sinead |date=2021-11-15 |title=How necessary and feasible are reductions of methane emissions from livestock to support stringent temperature goals? |journal=Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences |language=en |volume=379 |issue=2210 |pages=20200452 |bibcode=2021RSPTA.37900452R |doi=10.1098/rsta.2020.0452 |issn=1364-503X |pmc=8480228 |pmid=34565223}}</ref> [[selective breeding]],<ref name=":2" /> [[immunization]] against the many methanogens,<ref name=":2" /> rumen [[defaunation]] (killing the bacteria-killing protozoa),<ref>{{Cite journal |last1=L. Aban |first1=Maita |last2=C. Bestil |first2=Lolito |date=2016 |title=Rumen Defaunation: Determining the Level and Frequency of Leucaena leucocephala Linn. Forage |url=http://www.ijfe.org/uploadfile/2016/0512/20160512062938837.pdf |journal=International Journal of Food Engineering |volume=2 |issue=1}}</ref> diet modification (e.g. [[seaweed]] fortification),<ref>{{Cite news |last=Lewis Mernit |first=Judith |date=2 July 2018 |title=How Eating Seaweed Can Help Cows to Belch Less Methane |url=https://e360.yale.edu/features/how-eating-seaweed-can-help-cows-to-belch-less-methane |access-date=29 January 2022 |work=Yale School of the Environment}}</ref> decreased [[antibiotic]] use,<ref>{{Cite web |last=Axt |first=Barbara |date=25 May 2016 |title=Treating cows with antibiotics doubles dung methane emissions |url=https://www.newscientist.com/article/2089867-treating-cows-with-antibiotics-doubles-dung-methane-emissions/ |access-date=5 October 2019 |website=New Scientist}}</ref> and [[grazing]] management.<ref>{{Cite web |last=Willis |first=Katie |title=Grazing livestock could reduce greenhouse gases in the atmosphere, study shows |url=https://www.ualberta.ca/folio/2021/03/grazing-livestock-could-reduce-greenhouse-gases-in-the-atmosphere-study-shows.html |access-date=2024-04-10 |website=www.ualberta.ca |language=en}}</ref>
Measures that increase state revenues from meat consumption/production could enable the use of these funds [[Research and development#Government expenditures|for related research and development]] and "to cushion social hardships among low-income consumers". Meat and livestock are important sectors of the contemporary socioeconomic system, with livestock value chains [[employment|employing]] an estimated >1.3 billion people.<ref name="10.1146/annurev-resource-111820-032340" />
Sequestering carbon into soil is currently not feasible to cancel out planet-warming emissions caused by the livestock sector. The global livestock annually emits 135 billion metric tons of carbon, way more than can be returned to the soil.<ref>{{Cite journal |
[[Agricultural subsidy|Agricultural subsidies]] for cattle and their feedstock could be stopped.<ref>{{Cite news |last=Carrington |first=Damian |last2= |first2= |date=2021-09-14 |title=Nearly all global farm subsidies harm people and planet – UN |url=https://www.theguardian.com/environment/2021/sep/14/global-farm-subsidies-damage-people-planet-un-climate-crisis-nature-inequality |access-date=2024-03-27 |work=[[The Guardian]] |language=en-GB |issn=0261-3077}}</ref> A more controversial suggestion, advocated by [[George Monbiot]] in the documentary "Apocalypse Cow", is to stop farming cattle completely, however farmers often have political power so might be able to resist such a big change.<ref>{{Cite web |date=13 May 2022 |title=George Monbiot: "Agriculture is arguably the most destructive industry on Earth" |url=https://www.newstatesman.com/encounter/2022/05/george-monbiot-agriculture-is-arguably-the-most-destructive-industry-on-earth |access-date=4 June 2022 |website=[[New Statesman]]}}</ref>
==Effects on ecosystems==
=== Soils ===
[[File:ParaguayChaco Clearings for cattle grazing.jpg|thumb|Clearings for cattle grazing in the [[Gran Chaco|Chaco]] region of [[Paraguay]]]]Grazing can have positive or negative effects on rangeland health, depending on management quality,<ref>{{cite book |last1=Bilotta |first1=G. S. |
Overgrazing can decrease [[soil quality]] by constantly depleting it of necessary nutrients.<ref>National Research Council. 1994. Rangeland Health. New Methods to Classify, Inventory and Monitor Rangelands. Nat. Acad. Press. 182 pp.</ref> By the end of 2002, the US [[Bureau of Land Management]] (BLM) found that 16% of the evaluated 7,437 grazing allotments had failed to meet [[rangeland health]] standards because of their excessive grazing use.<ref>US BLM. 2004. Proposed Revisions to Grazing Regulations for the Public Lands. FES 04-39</ref> [[Overgrazing]] appears to cause soil [[erosion]] in many dry regions of the world.<ref name="Steinfeld2006" /> However, on US farmland, soil erosion is much less on land used for livestock grazing than on land used for crop production. According to the US [[Natural Resources Conservation Service]], on 95.1% of US pastureland, [[Sheet erosion|sheet]] and [[rill erosion]] are within the estimated [[soil loss tolerance]], and on 99.4% of US pastureland, [[wind erosion]] is within the estimated soil loss tolerance.<ref>NRCS. 2009. Summary report 2007 national resources inventory. USDA Natural Resources Conservation Service. 123 pp.</ref>[[File:Two cows grazing.jpg|thumb|Dryland grazing on the [[Great Plains]] in [[Colorado]]]]
Grazing can affect the [[Carbon sequestration|sequestration]] of carbon and nitrogen in the soil. This sequestration helps mitigate the effects of greenhouse gas emissions, and in some cases, increases ecosystem productivity by affecting [[nutrient cycle|nutrient cycling]].<ref>{{cite journal |last1=De Mazancourt |first1=C. |last2=Loreau |first2=M. |last3=Abbadie |first3=L. |year=1998 |title=Grazing optimization and nutrient cycling: when do herbivores enhance plant production? |journal=Ecology |volume=79 |issue=7 |pages=2242–2252 |doi=10.1890/0012-9658(1998)079[2242:goancw]2.0.co;2 |s2cid=52234485}}</ref> A 2017 meta-study of the scientific literature estimated that the total global soil carbon sequestration potential from grazing management ranges from 0.
In Canada, a review highlighted that the methane and nitrous oxide emitted from manure management comprised 17% of agricultural greenhouse gas emissions, while nitrous oxide emitted from soils after application of manure, accounted for 50% of total emissions.<ref>{{Cite journal |last1=Kebreab |first1=E. |last2=Clark |first2=K. |last3=Wagner-Riddle |first3=C. |last4=France |first4=J. |date=2006-06-01 |title=Methane and nitrous oxide emissions from Canadian animal agriculture: A review |journal=Canadian Journal of Animal Science |language=en |volume=86 |issue=2 |pages=135–157 |doi=10.4141/A05-010 |issn=0008-3984|doi-access=free }}</ref>
Manure provides environmental benefits when properly managed.
Also, small-ruminant flocks in North America (and elsewhere) are sometimes used on fields for removal of various crop residues inedible by humans, converting them to food. Small ruminants, such as sheep and goats, can control some invasive or [[noxious weed]]s (such as [[spotted knapweed]], [[tansy ragwort]], [[Euphorbia virgata|leafy spurge]], [[yellow starthistle]], [[tall larkspur]], etc.) on rangeland.<ref>{{cite web |title=Livestock Grazing Guidelines for Controlling Noxious weeds in the Western United States |url=https://www.webpages.uidaho.edu/rx-grazing/Livestock_Graizng_Guidelines(Davison_et_al.%202007).pdf |access-date=24 April 2019 |publisher=University of Nevada}}</ref> Small ruminants are also useful for vegetation management in forest plantations and for clearing brush on rights-of-way. Other ruminants, like Nublang cattle, are used in Bhutan to help
=== Biodiversity ===
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}}
Meat production is considered one of the prime factors contributing to the current [[Holocene extinction|biodiversity loss crisis]].<ref name="ReferenceA" /><ref>{{cite news |last=Woodyatt |first=Amy |date=May 26, 2020 |title=Human activity threatens billions of years of evolutionary history, researchers warn |work=[[CNN]] |url=https://www.cnn.com/2020/05/26/world/species-loss-evolution-climate-scn-intl-scli/index.html |access-date=May 27, 2020}}</ref><ref>{{Cite journal |
Grazing (especially [[overgrazing]]) may detrimentally affect certain wildlife species, e.g. by altering cover and food supplies. The growing demand for meat is contributing to [[Holocene extinction|significant biodiversity loss]] as it is a significant driver of [[deforestation]] and habitat destruction; species-rich habitats, such as significant portions of the Amazon region, are being converted to agriculture for meat production.<ref>{{cite web |url= https://www.theguardian.com/environment/radical-conservation/2015/oct/20/the-four-horsemen-of-the-sixth-mass-extinction|title=How humans are driving the sixth mass extinction|first=Jeremy |last=Hance|date=October 20, 2015|work=[[The Guardian]] |access-date=January 10, 2017}}</ref><ref name="ReferenceA">{{cite journal |last1=Morell |first1=Virginia |year=2015 |title=Meat-eaters may speed worldwide species extinction, study warns |url=https://www.science.org/content/article/meat-eaters-may-speed-worldwide-species-extinction-study-warns |journal=Science |doi=10.1126/science.aad1607}}</ref><ref name="Machovina 2015 419–431">{{cite journal|first1=B.|last1=Machovina|first2=K. J.|last2=Feeley|first3=W. J.|last3=Ripple|year=2015|title=Biodiversity conservation: The key is reducing meat consumption|journal=Science of the Total Environment|volume= 536|pages=419–431|doi=10.1016/j.scitotenv.2015.07.022|pmid=26231772|bibcode=2015ScTEn.536..419M}}</ref> World Resource Institute (WRI) website mentions that "30 percent of global forest cover has been cleared, while another 20 percent has been degraded. Most of the rest has been fragmented, leaving only about 15 percent intact."<ref>{{Cite web|url=https://www.wri.org/our-work/topics/forests|title=Forests|website=World Resources Institute|language=en|access-date=2020-01-24}}</ref> WRI also states that around the world there is "an estimated 1.5 billion hectares (3.7 billion acres) of once-productive croplands and pasturelands – an area nearly the size of Russia – are degraded. Restoring productivity can improve food supplies, [[water security]], and the ability to fight climate change."<ref>{{
A 2022 report from [[World Animal Protection]] and the [[Center for Biological Diversity]] found that, based on 2018 data, some 235 million pounds (or 117,500 tons) of pesticides are used for animal feed purposes annually in the United States alone, in particular [[glyphosate]] and [[atrazine]]. The report emphasizes that 100,000 pounds of glyphosate has the potential to harm or kill some 93% of species listed under the [[Endangered Species Act]]. Atrazine, which is banned in 35 countries, could harm or kill at least 1,000 listed species. Both groups involved in the report advocate for consumers to reduce their consumption of animal products and to transition towards [[plant-based diets]] in order to reduce the growth of factory farming and protect endangered species of wildlife.<ref>{{cite news |last=Boyle |first=Louise |date=February 22, 2022 |title=US meat industry using 235m pounds of pesticides a year, threatening thousands of at-risk species, study finds |work=[[The Independent]] |location= |url=https://www.independent.co.uk/climate-change/news/pesticides-factory-farm-wildlife-food-chain-vegan-b2017811.html |access-date=February 28, 2022}}</ref>
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=== Aquatic ecosystems ===
{{Bar chart|title=Mean [[Eutrophication|eutrophying emissions]] (water pollution by phosphates) of different foods per 100g of protein<ref name="Nemecek 987–992"
Global agricultural practices are known to be one of the main reasons for environmental degradation. Animal agriculture worldwide encompasses 83% of [[Farmland (disambiguation)|farmland]] (
In the [[Western United States]], many [[stream]] and riparian [[habitat]]s have been negatively affected by livestock grazing. This has resulted in increased [[phosphate]]s, [[nitrate]]s, decreased dissolved oxygen, increased temperature, [[turbidity]], and [[eutrophication]] events, and reduced [[species diversity]].<ref>{{cite journal |last1=Belsky |first1=A. J. |display-authors=etal |year=1999 |title=Survey of livestock influences on stream and riparian ecosystems in the western United States |journal=J. Soil Water Cons. |volume=54 |pages=419–431}}</ref><ref>{{cite journal |last1=Agouridis |first1=C. T. |display-authors=etal |year=2005 |title=Livestock grazing management impact on streamwater quality: a review |url=http://lshs.tamu.edu/docs/lshs/end-notes/livestock%20grazing%20management%20impacts%20on%20stream%20water%20quality-1995420186/livestock%20grazing%20management%20impacts%20on%20stream%20water%20quality.pdf |journal=Journal of the American Water Resources Association |volume=41 |issue=3 |pages=591–606 |bibcode=2005JAWRA..41..591A |doi=10.1111/j.1752-1688.2005.tb03757.x |s2cid=46525184}}</ref> Livestock management options for riparian protection include salt and mineral placement, limiting seasonal access, use of alternative water sources, provision of "hardened" stream crossings, herding, and fencing.<ref>{{cite web |date=2006-06-28 |title=Pasture, Rangeland, and Grazing Operations - Best Management Practices | Agriculture | US EPA |url=http://www.epa.gov/agriculture/anprgbmp.html |access-date=2015-03-30 |publisher=Epa.gov}}</ref><ref>{{cite web |year=2006 |title=Grazing management processes and strategies for riparian-wetland areas. |url=https://www.blm.gov/or/programs/nrst/files/Final%20TR%201737-20.pdf |publisher=US Bureau of Land Management |pages=105}}</ref> In the [[Eastern United States]], a 1997 study found that waste release from pork farms has also been shown to cause large-scale eutrophication of bodies of water, including the [[Mississippi River]] and Atlantic Ocean (Palmquist, et al., 1997).<ref>{{Cite journal |last=Williams |first=C. M. |date=July 2008 |title=Technologies to mitigate {{as written|envir|omental [sic]}} impact of swine production |journal=Revista Brasileira de Zootecnia |language=en |volume=37 |issue=SPE |pages=253–259 |doi=10.1590/S1516-35982008001300029 |issn=1516-3598|doi-access=free }}</ref> In North Carolina, where the study was done, measures have since been taken to reduce the risk of accidental discharges from manure lagoons, and since then there has been evidence of improved environmental management in US hog production.<ref name="Key">Key, N. et al. 2011. Trends and developments in hog manure management, 1998-2009. USDA EIB-81. 33 pp.</ref> Implementation of manure and wastewater management planning can help assure low risk of problematic discharge into aquatic systems.<ref name="Key" />
In Central-Eastern Argentina, a 2017 study found large quantities of metal pollutants (chromium, copper, arsenic and lead) in their freshwater streams, disrupting the aquatic biota.<ref name="Regaldo-2017">{{Cite journal |last1=Regaldo |first1=Luciana |last2=Gutierrez |first2=María F. |last3=Reno |first3=Ulises |last4=Fernández |first4=Viviana |last5=Gervasio |first5=Susana |last6=Repetti |first6=María R. |last7=Gagneten |first7=Ana M. |date=2017-12-22 |title=Water and sediment quality assessment in the Colastiné-Corralito stream system (Santa Fe, Argentina): impact of industry and agriculture on aquatic ecosystems |url=http://dx.doi.org/10.1007/s11356-017-0911-4 |journal=Environmental Science and Pollution Research |volume=25 |issue=7 |pages=6951–6968 |doi=10.1007/s11356-017-0911-4 |pmid=29273985 |hdl=11336/58691 |s2cid=3685205 |issn=0944-1344|hdl-access=free }}</ref> The level of [[chromium]] in the freshwater systems exceeded 181.
Animal agriculture contributes to [[Climate change|global warming]], which leads to [[ocean acidification]]. This occurs because as carbon emissions increase, a chemical reaction occurs between carbon dioxide in the atmosphere and ocean water, causing seawater acidification.<ref>{{Cite journal |date=2012 |title=Ocean acidification |url=https://www.jstor.org/stable/43748533 |journal=Journal of College Science Teaching |volume=41 |issue=4 |pages=12–13 |jstor=43748533 |issn=0047-231X}}</ref> The process is also known as the dissolution of inorganic carbon in seawater.<ref>{{Cite journal |last1=DONEY |first1=SCOTT C. |last2=BALCH |first2=WILLIAM M. |last3=FABRY |first3=VICTORIA J. |last4=FEELY |first4=RICHARD A. |title=Ocean Acidification |date=2009 |url=https://www.jstor.org/stable/24861020 |journal=Oceanography |volume=22 |issue=4 |pages=16–25 |doi=10.5670/oceanog.2009.93 |jstor=24861020 |issn=1042-8275|hdl=1912/3181 |hdl-access=free }}</ref> This chemical reaction creates an environment that makes it difficult for [[Marine biogenic calcification|calcifying organisms]] to produce protective shells and causes seagrass overpopulation.<ref>{{Cite journal |last1=Johnson |first1=Ashanti |last2=White |first2=Natasha D. |date=2014 |title=Ocean Acidification: The Other Climate Change Issue |url=https://www.jstor.org/stable/43707749 |journal=American Scientist |volume=102 |issue=1 |pages=60–63 |doi=10.1511/2014.106.60 |jstor=43707749 |issn=0003-0996}}</ref> A reduction in marine life can have an adverse effect on people’s way of life, since limited sea life may reduce food availability and reduce coastal protection against storms.<ref>{{Cite journal |date=2014 |title=Fisheries, Food Security, and Climate Change in the Indo-Pacific Region |journal=Sea Change |url=https://www.jstor.org/stable/resrep10916.12 |pages=111–121}}</ref>
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===Meat reduction and health===
[[File:Soy-whey-protein-diet.jpg|thumb|An insight to a vegetarian diet]]
With care, meat can be substituted in most diets with a wide variety of foods such as [[fungi]]<ref>{{cite web |title=Plant-based meat substitutes - products with future potential {{!}} Bioökonomie.de |url=https://biooekonomie.de/en/topics/in-depth-reports/plant-based-meat-substitutes-products-future-potential |website=biooekonomie.de |access-date=25 May 2022 |language=en}}</ref><ref>{{cite web |last1=Berlin |first1=Kustrim CerimiKustrim Cerimi studied biotechnology at the Technical University in |last2=biotechnology |first2=is currently doing his PhD He is interested in the broad field of fungal |last3=Artists |first3=Has Collaborated in Various Interdisciplinary Projects with |last4=Artists |first4=Hybrid |title=Mushroom meat substitutes: A brief patent overview |url=https://blogs.biomedcentral.com/on-biology/2022/01/28/mushroom-meat-substitutes-a-brief-patent-overview/ |website=On Biology |access-date=25 May 2022 |date=28 January 2022}}</ref><ref>{{cite journal |last1=Lange |first1=Lene |title=The importance of fungi and mycology for addressing major global challenges* |journal=IMA Fungus |date=December 2014 |volume=5 |issue=2 |pages=463–471 |doi=10.5598/imafungus.2014.05.02.10 |pmid=25734035 |pmc=4329327 |s2cid=13755426 |issn=2210-6340}}</ref> or "[[meat substitute]]s". However, substantially reducing meat intake could result in nutritional deficiencies if done inadequately, especially for children, adolescents, and pregnant and lactating women "in low-income countries".<ref name="10.1146/annurev-resource-111820-032340" /> A review suggests that the reduction of meat in people's diets should be accompanied by an increase in alternative sources of protein and micronutrients to avoid nutritional deficiencies for [[healthy diet]]s such as [[iron]] and [[zinc]].<ref name="10.1146/annurev-resource-111820-032340">{{cite journal |last1=Parlasca |first1=Martin C. |last2=Qaim |first2=Matin |title=Meat Consumption and Sustainability |journal=Annual Review of Resource Economics |date=5 October 2022 |volume=14 |pages=17–41 |doi=10.1146/annurev-resource-111820-032340 |issn=1941-1340|doi-access=free }}</ref> Meats notably also contain [[vitamin B12|vitamin B<sub>12</sub>]],<ref>{{cite journal |last1=Gille |first1=Doreen |last2=Schmid |first2=Alexandra |title=Vitamin B12 in meat and dairy products |journal=Nutrition Reviews |date=February 2015 |volume=73 |issue=2 |pages=106–115 |doi=10.1093/nutrit/nuu011 |pmid=26024497 |issn=1753-4887|doi-access=free }}</ref> [[collagen]]<ref>{{cite journal |last1=Weston |first1=A. R. |last2=Rogers |first2=R. W. |last3=Althen |first3=T. G. |title=Review: The Role of Collagen in Meat Tenderness |journal=The Professional Animal Scientist |date=1 June 2002 |volume=18 |issue=2 |pages=107–111 |doi=10.15232/S1080-7446(15)31497-2 |language=en |issn=1080-7446|doi-access=free }}</ref> and [[creatine]].<ref>{{cite journal |last1=Ostojic |first1=Sergej M. |title=Eat less meat: Fortifying food with creatine to tackle climate change |journal=Clinical Nutrition |date=1 July 2020 |volume=39 |issue=7 |pages=2320 |doi=10.1016/j.clnu.2020.05.030 |pmid=32540181 |s2cid=219701817 |language=English |issn=0261-5614}}</ref> This could be achieved with specific types of foods such as iron-rich [[bean]]s and a [[amino acid profile|diverse variety]] of protein-rich foods<ref>{{cite journal |last1=Mariotti |first1=François |last2=Gardner |first2=Christopher D. |title=Dietary Protein and Amino Acids in Vegetarian Diets—A Review |journal=Nutrients |date=4 November 2019 |volume=11 |issue=11 |pages=2661 |doi=10.3390/nu11112661 |pmid=31690027 |pmc=6893534 |issn=2072-6643|doi-access=free }}</ref> like [[red lentils]], plant-based protein powders<ref>{{cite journal |last1=Tsaban |first1=Gal |last2=Meir |first2=Anat Yaskolka |last3=Rinott |first3=Ehud |last4=Zelicha |first4=Hila |last5=Kaplan |first5=Alon |last6=Shalev |first6=Aryeh |last7=Katz |first7=Amos |last8=Rudich |first8=Assaf |last9=Tirosh |first9=Amir |last10=Shelef |first10=Ilan |last11=Youngster |first11=Ilan |last12=Lebovitz |first12=Sharon |last13=Israeli |first13=Noa |last14=Shabat |first14=May |last15=Brikner |first15=Dov |last16=Pupkin |first16=Efrat |last17=Stumvoll |first17=Michael |last18=Thiery |first18=Joachim |last19=Ceglarek |first19=Uta |last20=Heiker |first20=John T. |last21=Körner |first21=Antje |last22=Landgraf |first22=Kathrin |last23=Bergen |first23=Martin von |last24=Blüher |first24=Matthias |last25=Stampfer |first25=Meir J. |last26=Shai |first26=Iris |title=The effect of green Mediterranean diet on cardiometabolic risk; a randomised controlled trial |journal=Heart |date=1 July 2021 |volume=107 |issue=13 |pages=1054–1061 |doi=10.1136/heartjnl-2020-317802 |pmid=33234670 |s2cid=227130240 |language=en |issn=1355-6037}}</ref> and high-protein [[Wrap (food)|wraps]], and/or [[dietary supplement]]s.<ref name="10.1016/j.appet.2020.105058">{{cite journal |last1=Onwezen |first1=M. C. |last2=Bouwman |first2=E. P. |last3=Reinders |first3=M. J. |last4=Dagevos |first4=H. |title=A systematic review on consumer acceptance of alternative proteins: Pulses, algae, insects, plant-based meat alternatives, and cultured meat |journal=Appetite |date=1 April 2021 |volume=159 |pages=105058 |doi=10.1016/j.appet.2020.105058 |pmid=33276014 |s2cid=227242500 |language=en |issn=0195-6663|doi-access=free }}</ref><ref>{{cite journal |last1=Craig |first1=Winston John |title=Nutrition concerns and health effects of vegetarian diets |journal=Nutrition in Clinical Practice|date=December 2010 |volume=25 |issue=6 |pages=613–620 |doi=10.1177/0884533610385707 |pmid=21139125 |issn=1941-2452}}</ref><ref>{{Cite web |last1=Zelman |first1=Kathleen M. |last2=MPH |last3=RD |last4=LD |title=The Truth Behind the Top 10 Dietary Supplements |url=https://www.webmd.com/diet/features/truth-behind-top-10-dietary-supplements |access-date=2022-06-18 |website=WebMD |language=en}}</ref> Dairy and fish and/or specific types of other foods and/or supplements contain [[Omega-3 fatty acid|omega 3]], [[vitamin K2|vitamin K<sub>2</sub>]], [[vitamin D3|vitamin D<sub>3</sub>]], [[iodine]], [[magnesium]] and [[calcium]], many of which were generally lower in people consuming types of plant-based diets in studies.<ref>{{cite journal |last1=Neufingerl |first1=Nicole |last2=Eilander |first2=Ans |title=Nutrient Intake and Status in Adults Consuming Plant-Based Diets Compared to Meat-Eaters: A Systematic Review |journal=Nutrients |date=January 2022 |volume=14 |issue=1 |pages=29 |doi=10.3390/nu14010029 |pmid=35010904 |pmc=8746448 |language=en |issn=2072-6643|doi-access=free }}</ref><ref>{{Cite web |last1=Boston |first1=677 Huntington Avenue |last2=Ma 02115 +1495‑1000 |date=2012-09-18 |title=Vitamin K |url=https://www.hsph.harvard.edu/nutritionsource/vitamin-k/ |access-date=2022-06-18 |website=The Nutrition Source |language=en-us}}</ref>
Nevertheless, observational studies find beneficial effects from plant-based diets (compared to consumption of meat products) on health and mortality rates.<ref>{{cite journal |last1=Fadnes |first1=Lars T. |last2=Økland |first2=Jan-Magnus |last3=Haaland |first3=Øystein A. |last4=Johansson |first4=Kjell Arne |title=Estimating impact of food choices on life expectancy: A modeling study |journal=PLOS Medicine |date=8 February 2022 |volume=19 |issue=2 |pages=e1003889 |doi=10.1371/journal.pmed.1003889 |pmid=35134067 |pmc=8824353 |language=en |issn=1549-1676 |doi-access=free }}</ref><ref name="10.1146/annurev-resource-111820-032340" /><ref>{{cite journal |title=Quality of plant-based diet determines mortality risk in Chinese older adults |url=https://www.nature.com/articles/s43587-022-00178-z |access-date=27 May 2022 |journal=Nature Aging |date=March 2022 |volume=2 |issue=3 |pages=197–198 |language=en |doi=10.1038/s43587-022-00178-z|pmid=37118375 |s2cid=247307240 }}</ref><ref>{{cite journal |last1=Jafari |first1=Sahar |last2=Hezaveh |first2=Erfan |last3=Jalilpiran |first3=Yahya |last4=Jayedi |first4=Ahmad |last5=Wong |first5=Alexei |last6=Safaiyan |first6=Abdolrasoul |last7=Barzegar |first7=Ali |title=Plant-based diets and risk of disease mortality: a systematic review and meta-analysis of cohort studies |journal=Critical Reviews in Food Science and Nutrition |date=6 May 2021 |volume=62 |issue=28 |pages=7760–7772 |doi=10.1080/10408398.2021.1918628 |pmid=33951994 |s2cid=233867757 |issn=1040-8398}}</ref><ref>{{cite journal |last1=Medawar |first1=Evelyn |last2=Huhn |first2=Sebastian |last3=Villringer |first3=Arno |last4=Veronica Witte |first4=A. |title=The effects of plant-based diets on the body and the brain: a systematic review |journal=Translational Psychiatry |date=12 September 2019 |volume=9 |issue=1 |page=226 |doi=10.1038/s41398-019-0552-0 |pmid=31515473 |pmc=6742661 |language=en |issn=2158-3188}}</ref>
===Meat-reduction strategies===
Strategies for implementing meat-reduction among populations include large-scale [[Education#Development|education]] and awareness building to promote more sustainable consumption styles. Other types of policy interventions could accelerate these shifts and might include "[[rationing|restrictions]] or fiscal mechanisms such as [[meat tax|
Relevant to such a strategy, estimating the environmental impacts of food products in a [[standardization|standardized]] way – as has been done with [[Life-cycle assessment#LCA dataset creation|a dataset]] of more than 57,000 food [[Product (business)|products]] in supermarkets – could also be used to inform consumers or in [[policy]], making consumers more aware of the environmental impacts of animal-based products (or requiring them to take such into consideration).<ref>{{cite news |title=These are the UK supermarket items with the worst environmental impact |url=https://www.newscientist.com/article/2332392-these-are-the-uk-supermarket-items-with-the-worst-environmental-impact/ |access-date=14 September 2022 |work=New Scientist}}</ref><ref>{{cite journal |last1=Clark |first1=Michael |last2=Springmann |first2=Marco |last3=Rayner |first3=Mike |last4=Scarborough |first4=Peter |last5=Hill |first5=Jason |last6=Tilman |first6=David |last7=Macdiarmid |first7=Jennie I. |last8=Fanzo |first8=Jessica |last9=Bandy |first9=Lauren |last10=Harrington |first10=Richard A. |title=Estimating the environmental impacts of 57,000 food products |journal=Proceedings of the National Academy of Sciences |date=16 August 2022 |volume=119 |issue=33 |pages=e2120584119 |doi=10.1073/pnas.2120584119 |pmid=35939701 |pmc=9388151 |bibcode=2022PNAS..11920584C |language=en |issn=0027-8424|doi-access=free}}</ref>
Line 311 ⟶ 340:
== By type of animal ==
=== Cattle ===
{{See also|Environmental effects of meat production|Milk#Environmental impact|Deforestation of the Amazon rainforest|Beef#Environmental impact}}The production of [[cattle]] has a significant environmental impact, whether measured in terms of [[methane emissions]], land use, consumption of water, discharge of pollutants, or [[eutrophication]] of waterways.
{| class="wikitable" style="float:right; clear:left; margin:0 0 0.5em 1em;"
|+Estimated [[virtual water]] requirements for various foods<br>(m<sup>3</sup> water/ton)<ref>{{cite web|url=http://www.waterfootprint.org/Reports/Report12.pdf|title=Virtual Water Trade|publisher=Wasterfootprint.org|access-date=30 March 2015}}</ref>
!
!<small>Hoekstra<br>& Hung</small><br><small>(2003)</small>
!<small>Chapagain<br>& Hoekstra<br>(2003)</small>
!<small>Zimmer<br>& Renault<br>(2003)</small>
!<small>Oki et al.<br>(2003)</small>
!Average
|-
!Beef
|
|15,977
|13,500
|20,700
|16,730
|-
!Pork
|
|5,906
|4,600
|5,900
|5,470
|-
!Cheese
|
|5,288
|
|
|5,290
|-
!Poultry
|
|2,828
|4,100
|4,500
|3,810
|-
!Eggs
|
|4,657
|2,700
|3,200
|3,520
|-
!Rice
|2,656
|
|1,400
|3,600
|2,550
|-
!Soybeans
|2,300
|
|2,750
|2,500
|2,520
|-
!Wheat
|1,150
|
|1,160
|2,000
|1,440
|-
!Maize
|450
|
|710
|1,900
|1,020
|-
!Milk
|
|865
|790
|560
|740
|-
!Potatoes
|160
|
|105
|
|130
|}
{{Bar chart|title=Mean [[land use]] of different foods<ref name="Nemecek 987–992"/>|float=right|label_type=Food Types|data_type=Land Use (m<sup>2</sup>·year per 100 g protein)|bar_width=20|width_units=em|data_max=185|label1=[[Lamb and mutton|Lamb and Mutton]]|data1=185|label2=[[Beef]]|data2=164|label3=[[Cheese]]|data3=41|label4=[[Pork]]|data4=11|label5=[[Poultry]]|data5=7.1|label6=[[Egg as food|Eggs]]|data6=5.7|label7=[[Aquaculture|Farmed Fish]]|data7=3.7|label8=[[Peanut]]s|data8=3.5|label9=[[Peas]]|data9=3.4|label10=[[Tofu]]|data10=2.2|label11=|data11=|label12=|data12=|label13=|data13=}}
Significant numbers of dairy, as well as beef cattle, are confined in [[concentrated animal feeding operations]] (CAFOs), defined as "new and existing operations which stable or confine and feed or maintain for a total of 45 days or more in any 12-month period more than the number of animals specified"<ref>{{cite web |url=http://www.sustainabletable.org/issues/factoryfarming/ |title="What is a Factory Farm?" Sustainable Table |publisher=Sustainabletable.org |access-date=15 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120605014129/http://www.sustainabletable.org/issues/factoryfarming/ |archive-date=5 June 2012 }}</ref> where "[c]rops, vegetation, forage growth, or post-harvest residues are not sustained in the normal growing season over any portion of the lot or facility."<ref>US Code of Federal Regulations 40 CFR 122</ref> They may be designated as small, medium and large. Such designation of cattle CAFOs is according to cattle type (mature dairy cows, veal calves or other) and cattle numbers, but medium CAFOs are so designated only if they meet certain discharge criteria, and small CAFOs are designated only on a case-by-case basis.<ref name=size>{{cite web |url=http://www.epa.gov/npdes/pubs/sector_table.pdf |title="Regulatory Definitions of Large CAFOs, Medium CAFO, and Small CAFOs." Environmental Protection Agency Fact Sheet. |access-date=15 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20150924094619/http://www.epa.gov/npdes/pubs/sector_table.pdf |archive-date=24 September 2015 }}</ref>
A CAFO that discharges pollutants is required to obtain a permit, which requires a plan to manage nutrient runoff, manure, chemicals, contaminants, and other wastewater pursuant to the US [[Clean Water Act]].<ref>US Code of Federal Regulations 40 CFR 122.23, 40 CFR 122.42</ref> The regulations involving CAFO permitting have been extensively litigated.<ref>{{ cite court | litigants=Waterkeeper Alliance et al. v. EPA | vol= 399 | reporter= F.3d 486 | court= 2nd cir |date=2005}}{{pb}}{{ cite court | litigants=National Pork Producers Council, et al. v. United States Environmental Protection Agency | vol= 635 | reporter= F. 3d 738 | court=5th Cir | date=2011 }}</ref>
Commonly, CAFO wastewater and manure nutrients are applied to land at agronomic rates for use by forages or crops, and it is often assumed that various constituents of wastewater and manure, e.g. organic contaminants and pathogens, will be retained, inactivated or degraded on the land with application at such rates; however, additional evidence is needed to test reliability of such assumptions.<ref>Bradford, S. A., E. Segal, W. Zheng, Q. Wang, and S. R. Hutchins. 2008. Reuse of concentrated animal feeding operation wastewater on agricultural lands. J. Env. Qual. 37 (supplement): S97-S115.</ref> Concerns raised by opponents of CAFOs have included risks of contaminated water due to [[feedlot]] runoff,<ref name=Koelsch>{{cite web |url=http://www.cals.ncsu.edu/waste_mgt/natlcenter/sanantonio/balvanz.pdf |title=Applying Alternative Technologies to CAFOs: A Case Study |first1=Richard |last1=Koelsch |first2=Carol |last2=Balvanz |first3=John |last3=George|first4=Dan |last4=Meyer|first5=John |last5=Nienaber |first6=Gene |last6=Tinker |access-date=16 January 2018 |url-status=dead |archive-url=https://web.archive.org/web/20131017230339/http://www.cals.ncsu.edu/waste_mgt/natlcenter/sanantonio/balvanz.pdf |archive-date=17 October 2013 }}</ref> soil erosion, human and animal exposure to toxic chemicals, development of [[antibiotic resistant bacteria]] and an increase in ''[[E. coli]]'' contamination.<ref>{{cite web |url=http://web.missouri.edu/~ikerdj/papers/Fairfield%20IA%20-%20Economics%20of%20CAFOs.htm |title=Ikerd, John. The Economics of CAFOs & Sustainable Alternatives |publisher=Web.missouri.edu |access-date=15 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20140810081852/http://web.missouri.edu/~ikerdj/papers/Fairfield%20IA%20-%20Economics%20of%20CAFOs.htm |archive-date=10 August 2014 }}</ref> While research suggests some of these impacts can be mitigated by developing wastewater treatment systems<ref name=Koelsch /> and planting cover crops in larger setback zones,<ref>{{cite web |url=http://dda.delaware.gov/nutrients/Draft_TechStandards/CAFO_BMPassessment.pdf |title=Hansen, Dave, Nelson, Jennifer and Volk, Jennifer. Setback Standards and Alternative Compliance Practices to Satisfy CAFO Requirements: An assessment for the DEF-AG group |access-date=15 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20120502130352/http://dda.delaware.gov/nutrients/Draft_TechStandards/CAFO_BMPassessment.pdf |archive-date=2 May 2012 }}</ref> the [[Union of Concerned Scientists]] released a report in 2008 concluding that CAFOs are generally unsustainable and [[Cost externalizing|externalize costs]].<ref name=UCS>{{cite web |url=http://www.ucsusa.org/assets/documents/food_and_agriculture/cafos-uncovered.pdf |title=Gurian-Sherman, Doug. CAFOs Uncovered: The Untold Costs of Confined Animal Feeding Operations |access-date=15 October 2013 |url-status=live |archive-url=https://web.archive.org/web/20130126213408/http://www.ucsusa.org/assets/documents/food_and_agriculture/cafos-uncovered.pdf |archive-date=26 January 2013 }}</ref>
Another concern is [[manure]], which if not well-managed, can lead to adverse environmental consequences. However, manure also is a valuable source of nutrients and organic matter when used as a fertilizer.<ref>{{cite web |url=http://www.fao.org/ag/againfo/programmes/en/lead/toolbox/Tech/20ManMgn.htm |title=Manure management |publisher=FAO |access-date=15 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20130903054645/http://www.fao.org/ag/againfo/programmes/en/lead/toolbox/Tech/20ManMgn.htm |archive-date=3 September 2013 }}</ref> Manure was used as a fertilizer on about {{convert|15.8|e6acre|ha|order=flip|abbr=off}} of US cropland in 2006, with manure from cattle accounting for nearly 70% of manure applications to soybeans and about 80% or more of manure applications to corn, wheat, barley, oats and sorghum.<ref>McDonald, J. M. et al. 2009. Manure use for fertilizer and for energy. Report to Congress. USDA, AP-037. 53pp.</ref> Substitution of manure for synthetic fertilizers in crop production can be environmentally significant, as between 43 and 88 [[megajoule]]s of fossil fuel energy would be used per kg of nitrogen in manufacture of synthetic nitrogenous fertilizers.<ref>Shapouri, H. et al. 2002. The energy balance of corn ethanol: an update. USDA Agricultural Economic Report 814.</ref>
Grazing by cattle at low intensities can create a favourable environment for native herbs and [[forb]]s by mimicking the native grazers who they displaced; in many world regions, though, cattle are reducing [[biodiversity]] due to [[overgrazing]].<ref>E.O. Wilson, ''The Future of Life'', 2003, Vintage Books, 256 pages {{ISBN|0-679-76811-4}}</ref> A survey of refuge managers on 123 National Wildlife Refuges in the US tallied 86 species of wildlife considered positively affected and 82 considered negatively affected by refuge cattle grazing or haying.<ref>Strassman, B. I. 1987. [https://deepblue.lib.umich.edu/bitstream/handle/2027.42/48162/267_2005_Article_BF01867177.pdf?sequence=1 Effects of cattle grazing and haying on wildlife conservation at National Wildlife Refuges in the United States]. Environmental Mgt. 11: 35–44 .</ref> Proper management of pastures, notably [[managed intensive rotational grazing]] and grazing at low intensities can lead to less use of fossil fuel energy, increased recapture of carbon dioxide, fewer ammonia emissions into the atmosphere, reduced soil erosion, better air quality, and less water pollution.<ref name="UCS" />{{-}}
=== Pigs ===
Line 336 ⟶ 466:
*[[Veganism]]
<!-- please keep entries in alphabetical order -->
== Notes ==
{{reflist|group=note}}
==References==
{{Reflist|30em}}
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[[Category:Meat]]
[[Category:Climate change and agriculture]]
[[Category:Cattle]]
[[Category:Human impact on the environment]]
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