Key facts and findings
By the numbers: GHG emissions by livestock
- Total emissions from global livestock: 7.1 Gigatonnes of Co2-equiv per year, representing 14.5 percent of all anthropogenic GHG emissions. This figure is in line FAO’s previous assessment, Livestock’s Long Shadow, published in 2006, although it is based on a much more detailed analysis and improved data sets. The two figures cannot be accurately compared, as reference periods and sources differ.
- Cattle (raised for both beef and milk, as well as for inedible outputs like manure and draft power) are the animal species responsible for the most emissions, representing about 65% of the livestock sector’s emissions.
- In terms of activities, feed production and processing (this includes land use change) and enteric fermentation from ruminants are the two main sources of emissions, representing 45 and 39 percent of total emissions, respectively. Manure storage and processing represent 10 percent. The remainder is attributable to the processing and transportation of animal products.
- Cutting across all activities and all species, the consumption of fossil fuel along supply chains accounts for about 20 percent of the livestock sector’s emissions.
- On a commodity-basis, beef and cattle milk are responsible for the most emissions, respectively, contributing 41 percent and 20 percent of the sector’s overall GHG outputs. (This figure excludes emissions from cow manure and cattle used as draught power).
- They are followed by pig meat, (9 percent of emissions), buffalo milk and meat (8 percent), chicken meat and eggs (8 percent), and small ruminant milk and meat (6 percent). The remaining emissions are sourced to other poultry species and non-edible products.
- Emission intensities (i.e. emissions per unit of product) vary from commodity to commodity. They are highest for beef (almost 300 kg CO2-eq per kilogram of protein produced), followed by meat and milk from small ruminants (165 and 112kg CO2-eq.kg respectively). Cow milk, chicken products and pork have lover global average emission intensities (below 100 CO2-eq/kg.) (At the sub-global level, within each commodity type there is very high variability in emission intensitys, as a result of the different practices and inputs to production used around the world.
- 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.
- About 44 percent of livestock emissions are in the form of methane (CH4). The remaining part is almost equally shared between Nitrous Dioxide (N2O, 29 percent) and Carbon Dioxide (CO2, 27 percent). This means that livestock supply chains emit:
- Gt CO2-eq of CO2 per annum, or 5 percent of anthropogenic CO2 emissions (IPCC, 2007)
- 3.1 Gt CO2-eq of CH4 per annum, or 44 percent of anthropogenic CH4 emissions (IPCC, 2007)
- 2 Gt CO2-eq of N2O per annum, or 53 percent of anthropogenic N2O emissions (IPCC, 2007)
Efficient practices key to reducing emissions
There is a direct link between GHG emission intensities and the efficiency with which producers use natural resources, i.e. the amount of natural resources engaged in animal production, per unit of edible or non-edible output. For livestock production systems, nitrous oxide, methane and carbon dioxide emissions are losses of nitrogen, energy and organic matter that undermine efficiency and productivity. Possible interventions to reduce emissions are therefore to a large extent based on technologies and practices that improve production efficiency at animal and herd levels.
While mitigation interventions will need to be tailored to local objectives and conditions, currently available mitigation options discussed in FAO’s assessment include:
For ruminants – cows, mainly -- the greatest promise involves improving animal and herd efficiency. This includes using better feeds and feeding techniques, which can reduce methane (CH4) generated during digestion as well as the amount of CH4 and nitrous oxide (N2O) released by decomposing manure.
Improved breeding and animal health interventions to allow herd sizes to shrink (meaning fewer, more productive animals) will also help. And manure management that ensures recovery and recycling of nutrients and energy, plus the use of energy saving devices, also have a role to play.
Additionally, better management of grazing lands could improve productivity and create carbon sinks with the potential to help offset livestock sector emissions.
In monogastric production – primarily poultry and pig farming –“precision feeding,” breeding, and better animal health care offer ways to reduce emissions due to feed production and manure management. Switching to feed sources whose production is less energy-intensive, and to more sustainable sources of power would allow additional cuts.
There is currently a wide variability in production practices, even within similar production systems. This results in a large variation of emission intensity within those systems – what FAO calls “an emission intensity gap” between livestock operations that generate high emissions vs. those that put out low emissions per unit of product. FAO’s new report estimates that partially reducing this gap within existing production systems could cut emissions by about 30 percent.
Grassland carbon sequestration could further contribute to the mitigation effort by, with global estimates of about 0.6 GT CO2-eq per year.
Key policy areas for action
Extension and agricultural support services. This suite of approaches facilitates practice change for mitigation and production enhancement, by providing access to good practices and technologies and building capacity to implement them. . Commonly used approaches include communication, training, demonstration farms and establishing producers’ networks for knowledge sharing.
Research and development. R&D is necessary to build the evidence base for mitigation intervention and technologies. It is required to tailor adapted and effective mitigation strategies and plays an important role in refining existing technologies/practices to increase their applicability. R&D is also necessary for increasing the supply of new and improved mitigation technologies/practices.
Financial incentives. These include either ‘beneficiary pays’ mechanisms (abatement subsidies, carbon credit markets) or ‘polluter pays’ mechanisms (emissions tax, tradable permits). Economically efficient mechanisms for incentivizing the adoption of mitigation technologies/practices also include support (e.g. soft loans) to initial investments associated to the adoption of most efficient practices.
Market friction instruments. This includes measures that that seek to increase the flow of information about the emissions associated with different livestock commodities (e.g. labeling schemes). This can help consumers and producers to better align their consumption and production preferences with the emission profiles of these commodities.
Advocacy. Raising awareness about livestock’s role in tackling climate change, to influence and promote mitigation policy development for the sector.
NAMAs. The development of Nationally Appropriate Mitigation Actions for livestock are national level processes through which countries can develop sectoral mitigation policies that integrate other development objectives, and seek international support towards their implementation.
International agreements. These include commitments, both within and outside the UNFCCC that provide high level incentives to mitigate livestock sector emissions and ensure that mitigation effort is shared between the different sectors of the economy.
>> Back to main article