How to Reduce Methane Emissions in Agriculture

The question of how to reduce methane emissions in agriculture is an important one. It is not fully appreciated that science shows that the ONLY way to meet global temperature rise targets is to drastically reduce agricultural methane emissions now. This can be done by using tried and tested agricultural and waste sector biogas technology. No new technology is needed. It can be done now.

Methane emissions abatement will have an appreciable effect on the all-important greenhouse gases which trap the sun’s heat much quicker than carbon dioxide.

Introduction: Why Reducing Methane Emissions in Agriculture is Essential and How You Can Help

It’s is only us that say that it is imperative that we all learn how to reduce methane emissions. It is those people in agriculture that need to do the most to reduce them.

The highly authoritative report titled: “Global Methane Assessment” (2021), by the Climate and Clean Air Coalition (CCAC), United Nations Environment Programme (UNEP) makes this clear.

According to the Global Methane Assessment, human-caused methane emissions can be reduced by up to 45% this decade. Such reductions would prevent nearly 0.3°C of global warming by 2045, keeping the Paris Climate Agreement’s goal of limiting global temperature rise to 1.5 degrees Celsius (1.5 C) within reach.

For the first time, the assessment considers the costs and benefits of methane mitigation in terms of climate and air pollution, because methane is:

• a key component in the formation of ground-level ozone (smog),
• a powerful climate forcer and
• a dangerous air pollutant,
• a 45% reduction would prevent [by 2030]:
  • 260,000 premature deaths each year,
  • 775,000 asthma-related hospital visits each year,
  • 73 billion hours of lost labour due to extreme heat each year, and
  • 25 million tonnes of crop losses each year.

You can help by publicizing the benefits explained in this article, or by becoming a biogas plant owner!

How to Reduce Methane Emissions Globally? What the United Nations Environment Programme Sponsored 2021 Report Concludes

A 1.5^oC pathway will necessitate not only reversing the current rising trend in [temperature induced] methane emissions but also significantly reducing anthropogenic (man-made) methane emissions by 2030.

This could be accomplished through policies aimed at implementing specific controls in specific sectors.

Governments and industry organisations must implement policies to effect behavioural change if the outcome we all need in reduced global temperature rise is to be accomplished.

This will necessitate policies that result in broad, cross-sectoral emissions reductions, such as ambitious international agreements, such as:

• the Kigali Amendments pattern for reducing hydrofluorocarbon emissions [under which global agreements have been very successful in abating and restoring the ozone layer],
• imposition of emissions caps or taxes, as shown in the modelling presented in Section 4.3 of the “Global Methane Assessment” 2021 report, or a combination of such policies.

[A “carbon tax” levied on all forms of atmospheric carbon emissions is often suggested.]

Gender-responsive policies, particularly those promoting behavioural change, should be implemented.

Achieving methane reductions also necessitates:

• increased education and information about the economic and societal impacts of mitigation, which their Global Methane Assessment” 2021, aims to provide, as well as
• additional infrastructure to make use of reduced emissions in some sectors and
• a shift in economic incentives that [if misunderstood] may be misaligned, preventing even action with overall negative costs from being undertaken (See IEA 2020 report).

It is also worth noting that, due to the removal of co-emitted aerosols that come with a realistically paced phase-out of fossil fuels, even aggressive decarbonization will have very little net impact on near-term (first 20 years) temperatures. Shindell and Smith (2019).

The research which has already been done has shown that the only plausible way to reduce warming relative to the reference case over the next 20 years is to reduce greenhouse gases from non-fossil sources:

• such as methane and nitrous oxide from agriculture and waste,
• as well as fluorinated gases (Shindell and Smith 2019).

How to Reduce Methane Emissions from Agriculture and Waste

Reducing Methane Emissions from the Agriculture and Waste Sectors is identified alongside further fluorinated gas emissions as a major policy area that can make a difference according to the “Global Methane Assessment” 2021 report.

While both human and natural sources are causes of methane emissions, recent increases are mainly driven by human activities. These are derived from three industries (in round figures):

• fossil fuels (35%),
• waste (20%), and
• agriculture (40%).

Agriculture and waste management are major sources of human-caused methane emissions. Anaerobic digestion can contribute to emissions reduction by capturing methane from suitable biodegradable wastes and livestock manure. However, it cannot directly prevent enteric methane released by cattle and other ruminants, which requires different mitigation strategies.

Consequently, the total methane reduction achievable through anaerobic digestion is substantially smaller than the combined contribution of agriculture and waste to global methane emissions. The actual benefit depends on the feedstocks treated, the alternative waste-management practices, methane capture efficiency and emissions throughout the biogas system.

How to Reduce Methane Emissions in Agriculture

How to Reduce Methane Emissions in Agriculture: Understanding the Different Sources

Reducing agricultural methane emissions requires more than installing anaerobic digestion plants. Although anaerobic digestion (AD) is an important technology for controlling methane emissions from livestock manure and other biodegradable agricultural residues, it does not directly control methane produced by cattle and other ruminants during digestion.

To select the most effective emissions reduction measures, it is essential to distinguish between enteric methane emissions, methane from manure management, and methane deliberately captured for energy recovery in farm anaerobic digesters.

1. Enteric Methane: Emissions from Livestock Digestion

Enteric fermentation is the biological process through which microorganisms break down feed within the digestive systems of ruminant animals, including cattle and sheep.

During this process, methane is produced by microorganisms known as methanogenic archaea. Most enteric methane from cattle is released through belching rather than flatulence.

Enteric fermentation is the largest source of agricultural methane emissions in the United Kingdom.

According to the UK Government’s Methane Action Plan, cattle accounted for approximately 78% of the UK’s agricultural methane emissions in 2023. About 65% of agricultural methane emissions arose from cattle digestion, while approximately 12% came from cattle manure management. The published percentages are rounded.

Source: UK Methane Action Plan – Agriculture.

Important distinction: Installing an anaerobic digester to process cattle slurry does not directly capture methane generated inside the animals’ digestive systems.

Measures for reducing enteric methane include:

• Improving feed quality and digestibility.
• Using scientifically validated methane-suppressing feed additives where authorised and appropriate.
• Improving herd health, fertility and productivity to reduce emissions intensity.
• Selective breeding for improved feed efficiency and lower methane emissions.
• Changes in livestock management and agricultural production systems.

The effectiveness and suitability of these interventions vary with animal species, diet, management practices and local regulatory requirements.

2. Methane from Manure and Slurry Storage

A second important agricultural methane source is the decomposition of livestock manure and slurry.

When biodegradable organic matter is stored under oxygen-depleted conditions, methanogenic microorganisms may generate methane. This is particularly significant in liquid manure and slurry storage systems, including lagoons and storage tanks.

Methane generation depends on factors including:

• Manure composition and biodegradable organic matter content.
• Storage temperature and duration.
• Oxygen availability and storage configuration.
• Residual organic matter and previous biological treatment.
• The quantity and characteristics of material entering storage.

This is where anaerobic digestion and controlled methane capture can offer significant environmental benefits.

Rather than allowing methane to escape uncontrolled during manure storage, a suitably designed AD system converts part of the biodegradable organic matter into biogas within an enclosed process.

The recovered biogas can then be used to generate renewable heat or electricity, or upgraded into biomethane.

Other manure-management strategies may also reduce methane emissions. Depending on the farm and its circumstances, these may include reducing slurry storage times, separating solids, changing treatment or storage arrangements, and installing gas-tight covers with appropriate collection and treatment systems.

Simply covering a slurry tank without capturing or safely managing the gas produced does not guarantee a reduction in methane emissions.

3. Captured Methane: The Role of Farm Anaerobic Digesters

The methane produced within an agricultural anaerobic digester is chemically identical to methane released from manure storage or enteric fermentation. The important difference is that the digester is designed to collect and control the gas.

Biogas typically contains methane and carbon dioxide, along with smaller quantities of hydrogen sulphide, water vapour and other constituents.

When biogas is properly collected and used, the methane can provide useful energy instead of escaping directly into the atmosphere.

However, the environmental benefits depend on effective engineering and operation. Methane may escape from:

• Digester roofs, seals, pipework and valves.
• Pressure relief and emergency venting systems.
• Biogas upgrading equipment and methane-containing off-gases.
• Uncovered or inadequately sealed digestate storage facilities.
• Maintenance activities, equipment failures and poorly managed operating procedures.

Digestate may continue to generate methane after leaving the digester, particularly if appreciable biodegradable organic matter remains. Suitable retention times, process optimisation and controlled digestate storage are therefore important.

The International Energy Agency’s 2026 Global Methane Tracker identifies fugitive methane emissions from modern bioenergy facilities and recommends measures including improved equipment design, leak detection and repair, and effective operational controls.

Source: IEA – Global Methane Tracker 2026.

Comparison: Three Forms of Farm Methane

Why Anaerobic Digestion Is Important but Not the Only Solution

Agricultural methane mitigation requires a combination of technologies and management measures.

Anaerobic digestion is particularly valuable when it captures methane from manure and other organic materials that would otherwise decompose and release greenhouse gases. It can also supply renewable energy and produce digestate containing recoverable plant nutrients.

Nevertheless, AD does not directly solve the problem of enteric methane, which represents the majority of agricultural methane emissions in the UK.

The greatest overall reductions will therefore require action on both livestock digestion and manure management, supported by appropriate monitoring, farm management and emissions-reduction technologies.

For further technical discussion, see our article on Farm Digesters and the Reduction of Greenhouse Gas Emissions.

According to the “Global Methane Assessment” 2021 report, “behavioural changes” have the potential to significantly augment targeted methane controls. They say that these are especially important in the agricultural sector, where targeted interventions have the least relative impact.

In our opinion, this refers to the agricultural and waste management sectors developing and operating anaerobic digestion plants.

Using the biogas to carry out the digestion of these materials which, if left to current practices by default decomposes largely anaerobically in manure and slurry lagoons, and emits large quantities of methane.

If not sent to a biogas digester organic waste is often tipped in landfills in which at best no more than 50% methane collection can be achieved even applying best practices in landfill gas management.

The analysis of the”Global Methane Assessment” 2021, suggests that reducing methane emissions will require:

1. Behavioural changes, in which the whole concept of waste is overturned to look at waste as a resource in a circular economy that re-uses it’s organic materials by-products such as inedible food by anaerobic digestion (AD) and biogas production.
2. Reducing all food loss and waste [at source].
3. Improving livestock management to capture waste outputs in all forms and make use of them.
4. Moving all populations to healthier diets that at the global level include reduced consumption of ruminant-based foods. This action has the potential to provide up to 65–80 Mt/yr of additional methane emissions mitigation.

Of the above 1. and 3. fall within the remit of the agricultural and waste (circular economy) sectors and the use of AD and biogas.

“Though these face substantial structural barriers, widespread adoption of such measures alongside targeted controls could bring anthropogenic methane emissions in line with those in 1.5ºC scenarios.”

(“Global Methane Assessment” 2021)

How Much Will Reducing Methane Emissions Cost?

We quote the closing sentence of the conclusion of the “Global Methane Assessment” 2021 report, as follows:

“Results are relatively robust for the fossil fuel and waste sectors and indicate clearly that there is an enormous potential for methane emissions mitigation with benefits that greatly outweigh implementation costs.”

How to Reduce Methane Emissions? – By Our Support of Agricultural Biogas Says Obama

(April 2014) In a very welcome move, the White House has backed farm biogas production from manure and other feedstocks since Obama was the US President, apart from a hiatus during Trumps term.

The reason for governments supporting biogas production is that less methane will be leaked into the atmosphere.

I primary methane emission source is the huge slurry lagoons on large US dairy farms. They are anaerobic and they produce methane in large quantities, especially during summer, and the methane bubbles off straight into the atmosphere.

Measures to reduce farm methane emissions simply by covering the lagoons in a plastic membrane, and collecting and using the biogas in a gas engine to make electricity, will reduce US national methane emissions. These are implicated in climate change studies as a significant contributory source of global warming.

The US dairy industry not only came to this conclusion in 2009 but has been working since toward its own carbon footprint reduction targets ever since.

It only took a politician (Obama) 5 years to wake up to a “good thing” for the environment when he must have realised that by making this announcement he could take credit for it!

The news, which shows that the White House after 12 months of extreme weather conditions which by themselves have convinced an ever-increasing number of Americans that climate change not only exists, but it is already having a major impact on their lives.

In the summer of 2021, there was a flurry of reporting on this topic, and a biogas roadmap was published. We have included some quotes to give a flavour of America’s awakening to methane emissions below:

Dairy industry supports White House strategy to reduce methane emissions

In its announcement, the White House formally cited the work of the Innovation Center for U.S. Dairy’s Sustainability Council, whose efforts in part include a partnership with the USDA to proactively reduce agricultural greenhouse gas emissions, including methane.

“This announcement validates the path the dairy industry is on – one focused on proactive incentives that can increase farm income, not punitive regulations that would add more costs,” said Jim Mulhern, president and chief executive officer of the National Milk Producers Federation.

“Because of our recent efforts and farmers’ long-standing environmental stewardship, the White House strategy for agriculture includes a commitment to cost-effective, voluntary actions to reduce methane emissions through partnerships and programs.

Eager For A Climate Change Win, Obama Picks A Fresh Target: Methane – Forbes

In agriculture, belching, flatulent cattle are a focus. In June, the Unites States Department of Agriculture (USDA), EPA, and DOE will release a “biogas roadmap.” It will outline voluntary strategies (from the ranchers, not the cows) to speed up the …

Forbes Magazine

Of course, when it comes to food waste the most environmentally beneficial way to reduce methane emissions is not to produce waste food in the first place, and it is to Newsweek’s credit that their article recognizes this:

ᔥ Fixing Farming Without Breaking Food

Newsweek
Also with livestock, farmers could convert methane-laden manure into greener materials, such as compost or even electricity-yielding biogas. Consumers, on the other hand, can accomplish a lot simply by eating more responsibly. Almost half of the food …

Healthier, more efficient food systems could slash farm emissions – study Credits: Fixing Farming Without Breaking Food – Newsweek

Interestingly, commentators in the UK saw things in a slightly different light in the following article:

US government searching for “cow of the future” to save the environment

Telegraph.co.uk – One such example is the National Biogas Roadmap, announced by President Barack Obama, late last month, which will help install biogas digesters in slaughterhouses, dairies, and ranches that will capture methane gas released by the cows’ manure …