UPSC MAINS 2019: Study says cow urine may be a reason for global warming

Impact of Climate Change on Livestock


Topic: Study says cow urine may be a reason for global warming

Topic in Syllabus: General Studies Paper 3: Ecology and Environment


Study says cow urine may be a reason for global warming


Cow urine a minor fount of research in India for its medicinal benefits may also contribute to global warming. The urine from the ruminant is a source of nitrous oxide emissions (N2O), a gas that is 300 times more powerful than carbon dioxide. Most times, when cow urine is used in degraded pastures, which are also seen in vast tracts of land in India, N2O emissions are tripled, says a study conducted in Colombia, Argentina, Brazil, Nicaragua, Trinidad and Tobago, and published in the latest edition of the peer-reviewed Scientific Reports.


More about on news:

  • Cattle and livestock are important source of methane, a greenhouse gas. However, the role of cow urine is less understood. The study was conducted by the International Centre for Tropical Agriculture (CIAT).
  • Colombia in which the researchers collected urine from cattle and spilled 500 ml samples on paired cattle fields known as degraded or healthy. It was determined by vegetation coverage.
  • In six of the seven test sites, degraded pastures emitted significantly more N2O that was sometimes up to three times as much.
  • Dung and urine are commonly mixed together for manure in Indian fields.
  • India also has the world’s largest livestock population and many tracts of degraded land. The findings may have a bearing on nitrogen emissions from Indian fields.

Bovine Twist



  • Total emissions from global livestock: 7.1 Giga-tonnes of Co2-equiv per year, representing 14.5 percent of all anthropogenic GHG 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.
  • About 44 percent of livestock emissions are in the form of methane (CH4). The remaining part is almost equally shared between Nitrous Oxide (N2O, 29 percent) and Carbon Dioxide (CO2, 27 percent).
  • 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.
  • 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.



  • Livestock is commonly defined as domesticated animals raised in an agricultural setting to produce labor and commodities such as meat, eggs, milk, fur, leather, and wool.
  • The term is sometimes used to refer solely to those that are bred for consumption, while other times it refers only to farmed ruminants, such as cattle and goats.
  • Horses are considered livestock in the United States.


Sources of GHG emissions by livestock:

The bulk of GHG emissions by livestock originate from four main categories of activities: enteric fermentation, manure management, feed production and energy consumption.


Methane (CH4) emissions from enteric fermentation:

  • Ruminant animals (cattle, buffalo, sheep and goat) produce methane as part of their digestive process.
  • In their rumen (stomach), microbial fermentation breaks down carbohydrates into simple molecules that can be digested by the animals.
  • Methane is a by-product of this process. Highly fibrous feed rations because higher CH4 emissions per unit of energy ingested.
  • Non-ruminant species, such as pigs, do also produce methane but amounts are much lower by comparison (enteric fermentation from cattle, buffalo, small ruminants and pig, but not from poultry, is included in this assessment).


Methane (CH4) and nitrous oxide (N2O) emissions from manure management:

  • Manure contains two chemical components that can lead to greenhouse gas emissions during storage and processing: organic matter that can be converted in methane and nitrogen that leads to nitrous oxide emissions.
  • Methane is released from the anaerobic decomposition of organic material. This occurs mostly when manure is managed in liquid form, such as in deep lagoons or holding tanks.
  • During storage and processing, nitrogen is mostly released in the atmosphere as ammonia (NH3) that can be later transformed into N2O (indirect emissions).


Carbon dioxide (CO2) and nitrous oxide (N2O) emissions from feed production, processing and transport:

  • Carbon dioxide emissions originate from the expansion of feed crops and pasture into natural habitats, which causes the oxidation of C in soil and vegetation.
  • They also originate from the use of fossil fuel to manufacture fertilizer, and process and transport feed.
  • The emissions of N2O come from the use of fertilizers (organic or synthetic) for feed production and from the direct deposition of manure on pasture or during the management and application of manure on crop fields.
  • Direct or indirect N2O emissions can vary greatly according to temperature and humidity at the time of application and their quantification is thus subject to high uncertainty.


Carbon dioxide (CO2) emissions from energy consumption:

  • Energy consumption occurs along the entire livestock supply chains producing CO2 emissions.
  • At feed production level, it mostly relates to the production of fertilizers and to the use of machinery for crop management, harvesting, processing and transportation.
  • Energy is also consumed on the animal production site, either directly through mechanized operations, or indirectly for the construction of buildings and of equipment. Finally, processing and transportation of animal commodities involve further energy use.


Impact of Livestock on Climate Change:

  • The most important greenhouse gases from animal agriculture are methane and nitrous oxide.
  • Methane, mainly produced by enteric fermentation and manure storage, is a gas which has an effect on global warming 28 times higher than carbon dioxide.
  • Nitrous oxide, arising from manure storage and the use of organic/inorganic fertilizers, is a molecule with a global warming potential 265 times higher than carbon dioxide.
  • The carbon dioxide equivalent is a standard unit used to account for the global warming potential (IPCC, 2013).
  • In addition to greenhouse gases arising from enteric fermentation and manure storage, feed production together with the related soil carbon dioxide and nitrous oxide emissions is another important hot spot for the livestock sector.
  • Soil carbon dioxide emissions are due to soil carbon dynamics (e.g., decomposing plant residues, mineralization of soil organic matter, land use change, etc.), the manufacturing of synthetic fertilizers and pesticides, and from fossil fuel use in on-farm agricultural operations.
  • Nitrous oxide emissions are emitted when organic and inorganic fertilizers are applied to the soil.


Impact of climate change on livestock:


Impact of Climate Change on Livestock


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.

While mitigation interventions will need to be tailored to local objectives and conditions, currently available mitigation options discussed in FAO’s assessment include:

  • 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.
  • 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.


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.



Agriculture in general, and livestock production, in particular, contributes to global warming through emissions of methane and nitrous oxide. To meet future needs of an expanding population, animal productivity will need to increase and greenhouse gas emission intensity per unit of product will need to decrease. One of the principal ways to achieve this environmental standard is to adopt effective mitigation strategies. To increase the effectiveness of these strategies, complex interactions among the components of livestock production systems must be taken into account to avoid environmental trade-offs. Unfortunately, there is not a standard procedure to follow. Mitigation practices should not be evaluated individually, but as a component of the entire livestock production system.


Sample Question:

Critically examine impact of livestock on climate change?

Reason for global warming - Infographics