Generated Summary
This report presents a life cycle analysis of the GHG emissions arising from ruminant supply chains around the year 2005. The assessment is based on a life cycle assessment (LCA) and includes all main sources of emissions along the supply chain starting from land use and the production of feed, through emissions from animal production to emissions related to processing and transportation of products to the retail distribution point. This study aims to improve the understanding of greenhouse gas (GHG) emissions along livestock supply chains, identifying low-emission development pathways, and identifying mitigation strategies. The Global Livestock Environmental Assessment Model (GLEAM) was used to represent processes and activities from the production of inputs into the production process to the farm gate, the point at which products and animals leave the farm. The model recognized two farming systems for ruminant species (mixed and grazing). The main sources of GHG emissions in ruminant production are methane (CH4) from enteric fermentation, nitrous oxide (N2O) from feed production, and emissions from land-use change. The results of this assessment show that the average emission intensity for products from ruminants were estimated at 2.8, 3.4, and 6.5 kg CO2-eq/kg fat and protein corrected milk (FPCM) for cow milk, buffalo and small ruminant milk, respectively, and 46.2, 53.4, and 23.8 kg CO2-eq/kg carcass weight (CW) for beef, buffalo and small ruminant meat, respectively.
Key Findings & Statistics
- Globally, ruminant supply chains are estimated to produce 5.7 gigatonnes CO2-eq per annum, representing about 80 percent of the livestock sector emissions.
- Emissions from beef and milk production represent respectively 35 and 30 percent of the livestock sector emissions (equivalent to 4.6 gigatonnes CO2-eq).
- Buffalos and small ruminants supply chains have a much lower contribution, representing respectively 8.7 percent and 6.7 percent of sector emissions.
- The largest source of GHG emissions in ruminant production is methane (CH4) from enteric fermentation, which accounts for about 47 percent of the sector’s emissions and more than 90 percent of the total CH4 emissions.
- Nitrous oxide (N2O) emissions originating mainly from feed production and N deposited during grazing represent 24 percent of the sector’s GHG emissions.
- Emissions from land-use change associated with the expansion of grassland into forest account for 14.8 percent of total emissions related to beef production.
- In 2005, the global cattle sector produced approximately 508.6 million tonnes of milk and 61.4 million tonnes of beef, of which 56 percent of beef was produced by the specialized beef sector and 44 percent by the dairy herd.
- Globally, about 4 255.9 million tonnes of CO2-eq were emitted by the global cattle sector in 2005; of this 1 419.1 million tonnes were associated with milk production and 2 836.8 million tonnes with beef production.
- This is equivalent to 2.8 kg CO2-eq per kg of fat and protein corrected milk and 46.2 kg CO2-eq per kg of carcass weight.
- In 2005, global buffalo milk and meat production amounted to 115.2 and 3.4 million tonnes, respectively, and associated with this, about 389.9 and 180.2 million tonnes CO2-eq were emitted from the production of milk and meat from buffaloes, respectively.
- On average, the emission intensity of buffalo milk and meat is estimated at 3.4 kg CO2-eq/kg FPCM and 53.4 kg CO2-eq/kg CW, respectively.
- Globally, small ruminant production of meat and milk is responsible for 428.8 million tonnes CO2-eq, of which 254.4 million tonnes CO2-eq (59 percent) are associated with sheep production and 174.5 tonnes CO2-eq (41 percent) are associated with goat production.
- Total production from the small ruminant sector amounts to 20.0 and 12.6 million tonnes of milk and meat, respectively.
- On average, the emission intensity of small ruminant milk is 6.5 kg CO2-eq/kg FPCM.
- Average emission intensity for products from ruminants were estimated at 2.8, 3.4 and 6.5 kg CO2-eq/kg fat and protein corrected milk (FPCM) for cow milk, buffalo and small ruminant milk, respectively, and 46.2, 53.4, and 23.8 kg CO2-eq/kg carcass weight (CW) for beef, buffalo and small ruminant meat, respectively.
Other Important Findings
- The variation in emission intensities across regions and production systems for each commodity are driven by differences in production goals (specialized versus non-specialized production) and management practices, including animal husbandry methods, animal health and genetics which influence levels of productivity.
- In addition, there is a wide divergence in emission intensity for different commodities produced within the same region under comparable conditions (production systems and climatic zones) pointing to the existence of a considerable emission intensity gap.
- World regions show highly diverse emission intensities which are to large extent explained by their contribution to production, their production systems and management practices.
- Regional emission intensity of milk ranges from 1.6 kg CO2-eq/kg FPCM to 9.0 kg CO2-eq/kg FPCM.
- Generally, milk production in low productive systems has higher emission intensities than in high production systems of most affluent countries where better animal feeding and nutrition results in lower enteric and manure emissions and emission intensity at animal level.
- Emission intensity of beef at regional level show a great deal of diversity; ranging from 14 kg CO2-eq/kg CW in Eastern Europe and the Russian Federation to 76 kg CO2-eq/kg CW in South Asia.
- This difference in emission intensity of small ruminant meat and milk is due to variations in reproductive efficiency (resulting in a smaller “breeding overhead”), feed quality, and management practices that are generally poorer in developing regions.
Limitations Noted in the Document
- Due to the lack of globally validated model and databases, sequestration and losses of soil C arising from pasture management could not be included in the assessment but can be significant.
- The analysis covers emissions from the three major GHGs in agriculture, namely methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2), omitting gases of minor importance.
- This study focuses on emissions of the three major GHGs associated with animal food chains – methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) – as well as GHGs related to refrigerants.
- The assessment sets out to perform a complete LCA for the global livestock sector, using consistent calculation methods, modelling approaches, data and parameters for each production system within the sector. In contrast to previous LCA studies carried out for the livestock sector, which have primarily concentrated on either farm level or the national level emissions in OECD countries, this study is global in scope and includes both developed and developing countries.
- As a consequence of its global scope, the approach developed for this study has had to overcome onerous data requirements by relying on some simplifications that result in a loss of accuracy, particularly for systems at lower levels of aggregation.
- This assessment follows the attributional approach, which estimates the envi- ronmental burden of the existing situation under current production and market conditions, and allocates impacts to the various co-products of the production sys- tem. This differs from the consequential LCA approach, which considers potential consequences of changes in production, and relies on a system expansion analysis to allocate impacts of co-products (Thomassen et al., 2008).
Conclusion
The study highlights significant variations in emission intensities within supply chains, indicating potential for improvement. The key areas for mitigation include improving feeding practices and digestibility of diets, yields, and animal health; reducing land-use change; improving manure management; and enhancing energy use efficiency. The study underscores the importance of considering the impact on other environmental dimensions and broader development objectives, such as food security and poverty reduction, when assessing GHG mitigation measures. This comprehensive assessment of emissions from the ruminant sector is a foundational step towards identifying mitigation strategies, emphasizing the importance of understanding emission pathways and hotspots. By providing the most accurate information available on a global scale, this assessment helps to identify priority areas for mitigation and technical options that can reduce GHG emissions from the ruminant sector. It also provides a benchmark against which future trends can be measured. The analysis indicates that there are variations in emission intensities across regions and production systems, which are driven by factors such as production goals and management practices, including animal husbandry methods, animal health and genetics which influence levels of productivity. Moreover, the study found a wide divergence in emission intensity for different commodities produced within the same region under comparable conditions. The analysis also found a wide diversity in emission intensity at regional and production system level. These variations are largely driven by differences in production goals and management practices. In the context of jointly produced products, allocating emissions to each product according to its share of the products’ combined economic value may be considered, The largest source of GHG emissions in ruminant production is methane (CH4) from enteric fermentation, which accounts for about 47 percent of the sector’s emissions and more than 90 percent of the total CH4 emissions. In the dairy and beef sectors, nitrous oxide (N2O) emissions mainly originate from feed production and N deposited during grazing. The analysis highlights the need for continuous improvements in environmental performance along supply chains through harmonization of approaches and data. This calls for a need to clearly define and agree on methodologies for estimating GHG emissions from the ruminant sector.