Animal agriculture is a major contributor to climate change, yet it is so often overlooked in policy discussions. As much as 37 percent of greenhouse gas emissions globally are caused by our food and the way we produce it. In agriculture, the production of animal products is responsible for up to 78 percent of all emissions. As it is, the livestock sector produces more greenhouse gases (GHGs) than the direct emissions from all forms of transport.
A paper published in Nature in 2018 showed that on current trends, GHGs from food production and consumption would increase by 87 percent by the middle of the century. The bottom line is that as more people eat more meat from resource-intensive industrial agriculture, it creates a hothouse planet.
In many discussions about climate change, cows are cited as a big problem because of the methane they emit, while factory-farmed pigs and chickens are overlooked.
Industrial pigs and poultry may not emit large quantities of methane in the same way as ruminant animals, but their rearing still produces serious emissions. Carbon dioxide is released from the intensively managed soils needed to grow their feed. In addition, intensively reared pigs and poultry are fed soya from farmland in South America, where deforestation is a major source of carbon emissions. Scientists suggest that up to two-thirds of arable land globally is used to feed factory-farmed pigs, chickens and cattle, as well as to run biofuel-powered vehicles.
Growing feed for factory-farmed animals causes substantial emissions of nitrous oxide through the use of fertilisers. Nitrous oxide is the most aggressive greenhouse gas; 300 times more potent than carbon dioxide. It also depletes the ozone layer.
According to scientists, global nitrous oxide emissions have increased by 30 percent over the last forty years – a period that has seen major growth in the factory farming of pigs and chickens.
The numbers of pigs and poultry, on the other hand, their population running into tens of billions, continue to increase. And, as the burden of cropland needed to feed them expands, emissions of carbon into the atmosphere increases, too.
Introduction to the problem and scale
- There have always been natural fluctuations in the Earth’s temperature, but scientific evidence now shows that temperatures are rising faster than at any other time. The Earth has warmed by around 1ºC since the beginning of the Industrial Revolution and this has been
driven mainly by human activity.
- In 2019, the Intergovernmental Panel on Climate Change (IPCC) Report 2019 2 issued a warning that “rapid, far-reaching and unprecedented changes in all aspects of society” were required to limit global warming to 1.5ºC. The report went on to highlight that a “rise between 1.5ºC and 2ºC may push both human societies and natural ecosystems past critical thresholds for catastrophic change”. The IPCC report noted for the first time a clear link between lifestyle choices and warming, citing four key areas where change should take place: energy generation, land use, cities, and industry. The Special Report was commissioned as part of the 2015 Paris Agreement when 197 countries agreed to tackle manmade climate change.
- The Paris Agreement set a target to keep global warming below 2ºC, with a further aspiration to keep it within 1.5ºC. It provides a long-term direction of travel for countries along with a new system of regular five-year review cycles. In 2023, a ‘global stocktake’ will take place to measure overall progress towards achieving the Paris Climate targets. Governments agreed to publish their commitments known as Nationally Determined Contributions (NDCs) which outline proposed actions to be taken to reduce emissions. Country progress reports will take place every two years.
- According to the National Oceanic and Atmospheric Administration (NOAA) 2019 Global Climate Report, the five warmest years in the 1880–2019 record have all occurred since 2015, while nine of the 10 warmest years have occurred since 2005. 3
- As the Earth's average global temperature rises, the impact of extreme weather conditions will intensify, causing more severe droughts, heatwaves, hurricanes, and floods. Increased volatility of extreme weather patterns is already affecting farmers and food producers across the world affecting crop production and resulting in lost harvests. The Food and Agriculture Organization (FAQ) estimates that crop yields could fall between 10-25% by 2050 as a result of climate change. 4
- Sea levels are rising as glaciers and ice sheets melt due to global warming. It is estimated that these could rise to between 0.4m and 0.82m by 2018-2100. 5
- Rises in sea level will threaten the livelihoods of those living in coastal and river areas. This is currently estimated at 60% of the world population and will prompt large-scale migration - a cause for growing conflict. 6
- The climate crisis is also a health crisis: the same emissions that cause global warming are responsible for more than one-quarter of deaths from heart attack, stroke, lung cancer and chronic respiratory diseases. 7
- Increased carbon dioxide emissions are impacting the oceans and threatening many marine species and ecosystems. Ocean acidification negatively impacts corals, plankton, and shellfish. 8
- Warming oceans are leading to more outbreaks of algal blooms which negatively impact fish populations. 9
- Wild animal and plant populations are impacted– it is estimated that around 20-30% of plants and animals are likely to disappear as global temperatures rise between 1.5ºC and 2ºC.10
How does factory farming affect climate change?
- Globally, food systems are responsible for 20-30% of anthropogenic greenhouse gas (GHG).
emissions. 11 Transportation and distribution of food (i.e. food miles) are responsible for a fraction of GHG emissions compared to the production phase. 12
- A study published in Nature (2018) shows that globally, business as usual in food production
and consumption will lead to an 87% increase in GHG emissions by 2050 (compared with 2010). 13
- Within 10 years, the livestock sector could, if there is no reduction in global meat and dairy consumption, account for almost half (49%) of the world’s emissions budget allowable if we are to keep the increase in global warming to 1.5°C. 14
- Animal protein requires ten times as much energy to produce, as plant protein. 15 Deforestation, methane emissions and fertilizer use add further emissions.
- Livestock production is a key driver of deforestation as land is cleared to provide pasture and as cropland for animal feed production. 16
- Tackling climate change will be impossible without reducing meat consumption. 17 A significant reduction in meat and dairy consumption is essential if food-related emissions are to decrease and if the Paris targets are to be met. 18 19
- “The world’s current consumption pattern of meat and dairy products is a major driver of climate change and climate change can only be effectively addressed if demand for these products is reduced”, says Hilal Elver, UN Special Rapporteur on the right to food stresses. 20
- Enteric emissions and feed production (including manure deposition on pasture) dominate emissions from ruminant production. In pig supply chains, the bulk of emissions are related to the feed supply and manure storage in processing, while feed supply represents the bulk of
emissions in poultry production, followed by energy consumption. 21
Link to the relevant Sustainable Development Goal (SDG)
- SDG 13: Climate Action: Take urgent action to combat climate change and its impacts. 23
- BBC Science and Environment. What is Climate Change? Webpage. Accessed 4 November 2020
- IPCC, 2019: Summary for Policymakers. In: Climate Change and Land: an IPCC special report on
climate change, desertification, land degradation, sustainable land management, food security,
and greenhouse gas fluxes in terrestrial ecosystems [P.R. Shukla, J. Skea, E. Calvo Buendia, V.
Masson-Delmotte, H.- O. Pörtner, D. C. Roberts, P. Zhai, R. Slade, S. Connors, R. van Diemen, M.
Ferrat, E. Haughey, S. Luz, S. Neogi, M. Pathak, J. Petzold, J. Portugal Pereira, P. Vyas, E. Huntley,
K. Kissick, M. Belkacemi, J. Malley, (eds.)]. In press
- Climate Change: Global Temperature. Author: Rebecca Lindsey and LuAnn Dahlman. January 16,
- Source: FAO Transforming Food and Agriculture to achieve SDG’s
- Source: The International Union for Conservation of Nature (IUCN) IUCN (2015). Oceans and
Climate Change brochure.
- Source: Right to food. UN Secretary-General. UN General Assembly. 4 August 2015 and IPCC report.
- World Health Organisation: Urgent health challenges for the next decade. January 2020 Webpage Accessed 4 November 2020
- International Union for Conservation and Nature (IUCN) Issues Brief: Oceans and Climate Change.
November 2017. Webpage Accessed 4 November 2020
- Right to food. UN Secretary-General. UN General Assembly. 4 August 2015.
- CBS News reported statement as: ‘WWF reported that if the global temperature rose between 1.5
and 2.5 degrees Celsius, about 20 to 30 percent of the planet's animals and plants would
- Garnett, T., Smith, P., Nicholson, W., & Finch, J. (2016). Food systems and greenhouse gas
emissions (Food source: chapters). Food Climate Research Network, University of Oxford
- Food-Miles and the Relative Climate Impacts of Food Choices in the United States. Christopher L.
Weber and H. Scott Matthews. Environmental Science & Technology 2008 42 (10), 3508-3513.
- Springmann, M., Clark, M., Mason-D’Croz, D. et al. Options for keeping the food system within
environmental limits. Nature 562, 519–525 (2018)
- Harwatt, H., Ripple, W. J., Chaudhary, A., Betts, M. G. & Hayek, M. N. Scientists call for renewed Paris pledges to transform agriculture. Lancet Planet. Heal. (2019) doi:10.1016/S2542- 5196(19)30245-1 (accessed 4th October 2021).
- Pimentel, D. Sustainability of meat-based and plant-based diets and the environment. The
American Journal of Clinical Nutrition. Sept 2003.
- Bailey, R.et al., 2014. Livestock – Climate Change’s Forgotten Sector, Chatham House.
- Options for keeping the food system within environmental limits. Nature. 25 Oct 2018. P 2
- Bajželj, B., Richards, K., Allwood, J. et al. Importance of food-demand management for climate
mitigation. Nature Climate Change 4, 924–929 (2014).
- Bailey, R., Froggatt, A., Wellesley, L. 2014. Livestock – Climate Change’s Forgotten Sector.
- Hilal Elver, 2015. Interim Report. A/70/287.
- Tackling Climate Change through Livestock: A Global Assessment of Emissions and Mitigation
Opportunities, Rome: UN FAO. 2013, Full ref: Gerber, P.J., Steinfeld, H., Henderson, B., Mottet,
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A., Opio, C., Dijkman, J., Falcucci, A. & Tempio, G. 2013. Tackling climate change through livestock
– A global assessment of emissions and mitigation opportunities. Food and Agriculture Organization of the United Nations (FAO), Rome
- United Nations Department of Economic Social Affairs Sustainable Development