Methane emissions in Agriculture have emerged as a potent contributor to the climate crisis, prompting a growing interest in mitigating these emissions within crucial agricultural sectors.
To raise awareness of actionable solutions and offer a range of approaches, the Food and Agriculture Organization of the United Nations (FAO) has released a comprehensive report titled “Methane Emissions in Livestock and Rice Systems: Sources, Measurement, Mitigation, and Metrics.“
This extensive report was collaboratively compiled by a team of 54 international scientists and experts affiliated with the Livestock Environmental Assessment and Performance (LEAP) Partnership, which has been hosted at FAO since 2012. It provides a detailed examination and robust analysis of methane emissions in both livestock and rice systems. The report delves into the sources and sinks of methane gas, outlines methodologies for measuring emissions, explores a wide array of mitigation strategies, and evaluates metrics for tracking emissions and their reduction within the climate system.
In her foreword to the report, FAO Deputy Director-General Maria Helena Semedo notes, “The results and recommendations of this report reinforce the commitment of countries and stakeholders to reducing methane emissions, thereby advancing us toward more efficient, inclusive, resilient, low-emission, and sustainable agrifood systems.”
METHANE EMISSIONS IN AGRICULTURE
Methane constitutes approximately 20 percent of global greenhouse gas emissions and possesses more than 25 times the heat-trapping potential of carbon dioxide.
Currently, anthropogenic methane emissions contribute around 0.5 degrees. Reducing these emissions is a critical step toward achieving the goals of the Paris Agreement. This report aims to assist agrifood systems in meeting their commitments under the Global Methane Pledge, a non-binding initiative endorsed by over 150 countries to reduce methane emissions by 30 percent from 2020 levels by 2030. Such reductions could prevent more than 0.2 degrees Celsius of average global temperature increase by 2050.
This work aligns closely with the FAO Strategy on Climate Change and the Strategic Framework 2022-2031, both of which aspire to reduce greenhouse gas emissions through a holistic approach that includes improving production, nutrition, the environment, and quality of life—the Four Betters.
OTHER HUMAN ACTIVITIES
Beyond agrifood systems, other human activities generating methane emissions include landfills, oil and natural gas systems, coal mines, and more. About 32 percent of global anthropogenic methane emissions stem from microbial processes during the enteric fermentation of ruminant livestock and manure management systems, while another 8 percent arises from rice paddies.
Measuring methane emissions presents unique challenges, particularly in determining the most effective mitigation strategies. Precise methods exist, often involving respiration chambers for animals, but they are costly, labour-intensive, and less applicable to grazing animals. The use of drones and satellites has been explored but requires further validation.
Moreover, enteric methane emissions can vary significantly among animals of the same species, suggesting opportunities for genetic selection and dietary innovations in livestock feed.
Another important factor is the role of local soils as methane sinks. Research summarized in the report shows that upland forest soils, especially in temperate biomes, are the most efficient at this, with storage rates four times greater than those of cropland. Dry grazing lands also exhibit notably higher uptake rates than moist grazing lands. These findings point to the potential benefits of sylvopastoral approaches, as demonstrated in a Globally Important Agricultural Heritage System in Portugal.
Enhancing empirical data collection and establishing systematic measurement standards will enable more tailored local mitigation approaches.
Research into mitigating enteric methane has expanded, particularly in areas like feed mixtures, livestock breeding, and rumen manipulation.
The report discusses numerous available strategies, with a focus on their feasibility in various production systems. FAO assesses these strategies based on their impact on reducing methane production per animal product unit, safety considerations, interactions with other greenhouse gases, and economic, regulatory, and societal factors affecting implementation.
A similar analysis is conducted for rice paddy production systems, emphasizing the importance of engaging all levels of the supply chain to ensure shared responsibility for methane reduction.