Generated Summary
This document presents an analysis of livestock manure and its environmental impacts, focusing on data from 1990 to 2018. It utilizes FAOSTAT data to examine livestock manure production, nitrogen (N) inputs, and greenhouse gas (GHG) emissions. The study explores global and regional trends, emphasizing the role of livestock in environmental pollution, including volatilization, leaching, and GHG emissions. The methodology involves analyzing livestock standard units (LSU), manure production, and the impact of manure on agricultural soils and the environment. It provides insights into the environmental effects of livestock farming and highlights the need for sustainable agricultural practices.
Key Findings & Statistics
- In 2018, the world total livestock manure reached 125 million tonnes of nitrogen (N).
- 88 million tonnes N were left on pasture by grazing animals.
- 34 million tonnes N were treated in manure management systems.
- 27 million tonnes N applied to soils for crop production.
- N inputs from livestock manure to agricultural soils increased by 23 percent over 1990–2018.
- The global environmental impact of this manure in 2018 was nearly 60 million tonnes N.
- Over 20 million tonnes N dispersed in the air, mostly as ammonia gas, and 35 million tonnes N leached in aquifers and water bodies.
- Livestock-related GHG emissions amounted globally to 3.5 billion tonnes CO2eq in 2018, 15 percent higher than in 1990.
- These livestock emissions represented two-thirds of all emissions from agriculture.
- Asia had the largest share of livestock manure and associated environmental impacts.
- China, Brazil, India, and the USA were among the top countries generating the most livestock manure and related emissions.
- In 2018 there were 1.9 billion livestock units (LSU) in total, specifically 965 million cattle; 242 million pigs; 237 million chickens; 226 million sheep and goats.
- Since 1990, LSU stocks of cattle, buffaloes, sheep and goats, swine had increased by 16 percent, while chicken numbers increased more than two-folds.
- In 2018, world total production of livestock manure was 125 million tonnes N, a 23 percent increase since 1990.
- Manure left on pasture was roughly 88 million tonnes N (+43 percent since 1990).
- Manure treated in management systems was 34 million tonnes N.
- The world total amount of livestock manure deposited in 2018 on agricultural land was therefore 116 million tonnes N.
- Over the period 1990–2018, the N inputs from manure treated and applied to soils increased by 4 percent only while the amount of N in manure directly left on pastures increased by 30 percent.
- In 2018, annual GHG emissions from livestock manure were more than 1.4 billion tonnes CO2eq.
- 875 million tonnes CO2eq from manure left on pasture.
- 190 million tonnes CO2eq from manure applied to soils.
- 347 million tonnes CO2eq as methane lost in manure management systems.
- Annual GHG emissions from enteric fermentation were nearly double those generated from manure processes, with a world total in 2018 of 2.1 billion tonnes CO2eq.
- In 2018 the total impact of livestock was about 3.5 billion tonnes CO2eq, or about two-thirds of all GHG emissions produced from all production processes located within the farm gate.
- In 2018, more than 40 percent of world livestock, expressed in LSU, was in Asia (770 million LSU).
- About 30 percent in the Americas (540 milion LSU), 20 percent in Africa (330 million LSU).
- Over the period 1990 to 2018, the livestock population grew at an average annual rate of 2.3 percent in Africa, surpassing Asia (1.2 percent) and the Americas (0.8 percent).
- In 2018, livestock manure deposited annually on agricultural soils was largest in Asia (40 million tonnes N, up 50 percent since 1990), followed by the Americas (30 million tonnes N, up 20 percent) and Africa (also 30 million tonnes N, however it doubled since 1990).
- In 2018 China had the largest population of livestock, expressed in standard units (270 million LSU), followed by India (180 million LSU) and Brazil (170 million LSU).
- In 2018, Brazil, China, India, Ethiopia and the United States of America (USA) were the countries with the most livestock manure N left on pasture (mainly by cattle), with annual amounts ranging 3–9 million tonnes N.
- The methane (CH4) generated from enteric fermentation, mostly of ruminants, is the main contributor to world total livestock GHG emissions.
- In 2018, the country with the largest annual emissions from enteric fermentation, was India (292 million tonnes CO2eq).
Other Important Findings
- The document highlights the increase in N inputs from livestock manure to agricultural soils and the global environmental impact of this manure, including air and water pollution.
- It identifies Asia as having the largest share of livestock manure and associated environmental impacts, with Africa showing the fastest growth in manure production and GHG emissions since 1990.
- The study notes a prevalence of extensive production systems worldwide and significant opportunities for further development of manure management systems.
- It provides detailed statistics on GHG emissions from livestock manure, including emissions from enteric fermentation and manure management.
- The analysis includes regional variations in livestock populations and manure management practices, emphasizing the role of Asia, the Americas, and Africa.
- The document highlights that the USA and China had the largest amounts of livestock manure N applied to soils.
- The study showed that in 2018 swine contributed 30 percent to the total manure treated and applied to soils in China, whereas in the USA the largest source was dairy cattle (23 percent).
- It provides detailed statistics on GHG emissions from livestock manure, including emissions from enteric fermentation and manure management.
- It highlights the impact on pollution in terms of excess N in 2018 was 58 million tonnes N, or 50 percent of the total manure deposited on agricultural land.
Limitations Noted in the Document
- The study relies on the IPCC Tier 1 approach, which may lack detail on key drivers such as differences in livestock management systems and feeding regimes.
- The analysis is limited to the period 1990-2018, which may not fully capture long-term trends or recent developments in livestock farming and manure management.
- The document acknowledges the limitations of estimates made with the IPCC Tier 1 approach, notably a lack of important detail on key drivers such as differences in livestock management systems, feeding regimes, etc., which would become important when analysing future mitigation options.
Conclusion
The document presents a comprehensive overview of the environmental impacts of livestock manure, emphasizing the need for sustainable practices. The analysis underscores the significant contribution of livestock farming to GHG emissions and environmental pollution, highlighting the importance of effective manure management systems. The data reveals the complexity of environmental impacts, from the loss of nitrogen in pastures to the emissions of potent GHGs like methane. The findings also highlight regional disparities, with Asia and the Americas having the largest impacts and Africa experiencing rapid growth. The analysis also stresses the importance of adopting sustainable practices to mitigate the environmental effects of livestock production. The study reveals that the amount of N in manure directly left on pastures increased by 30 percent over the period 1990-2018, which indicates a prevalence of extensive production systems. The document further notes that the USA and China had the largest amounts of livestock manure N applied to soils, reflecting the scale of intensive agriculture. The study’s findings stress the critical need for improved manure management, offering significant potential for reducing environmental impacts. Finally, the findings point out that Asia and the Americas were the dominant regions in 2018, each emitting annually more than 1 billion tonnes CO2eq. The document highlights the importance of tailored solutions that consider regional differences and the evolution of livestock production systems. The analysis is a call to action to foster more sustainable practices and contribute to reducing the environmental footprint of the livestock industry, with effective management practices in order to achieve a more sustainable and environmentally friendly future for livestock farming worldwide.