Abstract
Animal agriculture is responsible for 8-10.8% of global greenhouse gas (GHG) emissions as assessed by IPCC accounting and, on the basis of lifecycle analysis, the contribution of livestock is up to 18% of global emissions. Asia is the source of the most enteric CH4 emissions with Latin America, Africa, Western Europe and North America being significant sources. These emissions are dominated by emissions from cattle. When GHG emissions are related to food production, the four most efficient regions are Eastern and Western Europe, North America, and the non-EU former Soviet Union which produced 46.3% of ruminant meat and milk energy and only 25.5% of enteric CH4 emissions in 2005. In comparison, the three least efficient producers (Asia, Africa, Latin America) produced an equivalent amount (47.1%) of ruminant meat and milk energy, and almost 69% of enteric CH4 emissions in 2005. Livestock related emissions will increase as world population and food demand increases; enteric CH4 emissions are projected to grow by over 30% from 2000 to 2020. There are mitigations available now, but it is imperative to develop new mitigations and ways to implement existing technologies more cost effectively. This paper is part of the special issue entitled: Greenhouse Gases in Animal Agriculture Finding a Balance between Food and Emissions, Guest Edited by T.A. McAllister, Section Guest Editors; K.A. Beauchemin, X. Hao, S. McGinn and Editor for Animal Feed Science and Technology, P.H. Robinson.
Generated Summary
This journal article, part of a special issue on greenhouse gases in animal agriculture, examines the significance of livestock as a contributor to global greenhouse gas emissions, both currently and in the near future. The study uses data from the Intergovernmental Panel on Climate Change (IPCC) and other sources, focusing on the regional distribution of these emissions, their relationship to food production, and potential mitigation strategies. The research approach includes lifecycle analysis to assess the contribution of livestock to global emissions, considering factors such as enteric fermentation, manure management, and deforestation. The scope of the study encompasses various regions, assessing the role of different livestock species and their impact on greenhouse gas (GHG) emissions. It also addresses the expected trends in future emissions, and analyzes possibilities for mitigation at a global level.
Key Findings & Statistics
- Animal agriculture is responsible for 8-10.8% of global greenhouse gas (GHG) emissions, as assessed by IPCC accounting.
- The contribution of livestock is up to 18% of global emissions based on lifecycle analysis.
- Asia is the source of the most enteric CH4 emissions.
- The four most efficient regions in terms of food production are Eastern and Western Europe, North America, and the non-EU former Soviet Union.
- These efficient regions produced 46.3% of ruminant meat and milk energy and only 25.5% of enteric CH4 emissions in 2005.
- The three least efficient producers (Asia, Africa, Latin America) produced an equivalent amount (47.1%) of ruminant meat and milk energy and almost 69% of enteric CH4 emissions in 2005.
- Livestock-related emissions will increase as the world population and food demand increase.
- Enteric CH4 emissions are projected to grow by over 30% from 2000 to 2020.
- Livestock related GHG emission estimates from FAO (2006a) allocated to IPCC emission source category:
- Of total livestock related emissions of 7.1 billion tonnes of CO2 equivalent (CO2-equiv.), 4.26 billion tonnes, or 60%, would be counted in the agriculture sector by IPCC.
- Livestock related emissions from FAO (2006a) that would be counted in the agriculture sector by IPCC equal 10.8% of global emissions.
- Estimates of livestock’s contribution to total global GHG emissions range from 8 to 10.8%.
- Total global emissions of enteric CH4 to be 1929 million tonnes of CO2-equiv., or 91.9 million tonnes CH4 in 2005.
- Global GHG emissions from manure management were 446 million tonnes of CO2-equiv. in 2005 (EPA, 2006) with 53% of this being CH4 and 47% N2O.
- World milk production is dominated by cow’s milk, which makes up 84% of total milk production.
- In 2005, 245 million tonnes of meat was produced globally, of which 30.8% was ruminant meat, mainly beef.
- World food demand is expected to rise by 1.5%/yr to 2030, and by 0.9%/yr thereafter to 2050.
- Bovine meat production is expected to have a higher growth rate 2000–2030 (1.3%/yr) than it had in the 1990’s of 0.7%/yr.
- Production of milk and dairy produce is expected to expand by 1.4%/yr in 2000 to 2030, up from 1.1%/yr in the 1990’s.
- The technical mitigation potential for agricultural emissions of 5500 to 6000 million tonnes CO2-equiv./yr by 2030.
- The technical mitigation potential for CH4, as enteric fermentation, manure management and rice management, was only 9% of the total, or ~500 million tonnes CO2-equiv./yr.
Other Important Findings
- Asia is the source of the most enteric CH4 emissions, with significant contributions from Latin America, Africa, Western Europe, and North America.
- Emissions are dominated by cattle, and the most efficient regions in terms of food production have lower enteric CH4 emissions.
- Deforestation accounts for a significant portion of GHG emissions from the livestock sector.
- The study notes substantial regional variations in emissions, with significant differences among individual countries.
- Under a ‘business as usual’ scenario, GHG emissions from livestock and agriculture are expected to grow as food production expands.
- The highest proportional reductions of enteric CH4 were from improved feeding, particularly with dairy cows.
Limitations Noted in the Document
- The EPA (2006) numbers to distinguish among sources.
- Emissions considered in Figs. 3 and 4 do not include emissions associated with land use change, which are relevant for grain fed meat and milk production.
- Technical mitigations have cost implications for producers, making the actual potential lower than the technical potential.
- The emissions associated with deforestation to bring land into production for pastures, production of animal feeds could greatly increase GHG emissions.
Conclusion
The article highlights the substantial contribution of livestock to global GHG emissions, emphasizing that animal agriculture is a significant source of GHGs, responsible for a considerable percentage of total global emissions. The study highlights regional variations in emission sources, particularly enteric CH4, and the impact of deforestation on overall GHG emissions. The research underscores the need for mitigation strategies, focusing on improved feeding practices, manure management, and land use practices. There is a substantial technical mitigation potential for livestock-related GHG emissions, but the implementation of these measures will significantly reduce the potential, due to the high costs involved. The article concludes that livestock production is a source of GHG that will increase as food production rises, necessitating progress in mitigation technologies. The article emphasizes the need to develop new technologies and ways to cost-effectively implement existing technologies to reduce emissions from the livestock sector. This can be achieved through approaches such as optimizing feeding practices, enhancing manure management, and improving land-use practices, alongside addressing the economic and practical challenges associated with implementing these strategies. The study suggests that mitigation efforts should focus on regions with high emission rates to maximize their impact on reducing the overall environmental footprint of livestock production.