What is our assessment?

Based on our analysis, grass-finished beef production has higher emissions of enteric methane and emissions from land use conversion than does conventional beef production, and would increase risks of biodiversity loss if scaled to meet current demand. Therefore, it is "Not Recommended" as a climate solution.

What is it?

Grass-finished beef production involves raising cattle exclusively on available pasture for their entire lives, eliminating the need for feed crops and associated resources. All cattle begin life on pasture; however, in conventional beef production, the animals spend their final four to six months in high-density feedlots, often called concentrated animal feeding operations (CAFOs). In these systems, cattle are fed high-calorie, mostly grain-based-energy feeds to gain weight quickly. The animals put on one-third to one-half of their total weight during this time, to reach slaughter weight by ~18 months. In contrast, grass-finished beef production requires ~24 to 28 months for animals to reach market weight on forage alone. 

Cattle raised entirely on grazing with no other feed inputs provide only about 1% of global protein. Using broader definitions of grass-finished that allow supplementary forage increases the global beef that would qualify to roughly one-third of global production (about 2–3% of global protein). Grass-fed cattle often receive supplementary feed in pasture-based systems in places such as Brazil, Ireland, and Australia, particularly during seasonal feed shortages.

Does it work?

Deploying grass-finished beef is not an effective climate mitigation strategy. Grass-finished cattle eat a more fibrous diet that produces higher methane emissions per unit of energy intake, and they take longer to reach market weight, resulting in higher lifetime methane emissions per animal. One widely cited study found that forage-fed cattle produce around four times more methane per unit of digestible energy intake than those fed corn- and grain-based diets. In addition, slower weight gain and longer production time require more grazing land, which would likely increase emissions from deforestation and other land use change. Life-cycle assessments consistently show higher emissions per kilogram for grass-finished beef than for grain-finished beef. Even the most efficient grass-finished systems produce 10–25% more emissions per kilogram of protein than grain-finished U.S. beef, and three to over 40 times more than a wide range of plant and animal protein alternatives.

Why are we excited?

Interest in grass-finished beef reflects a broader effort to reduce the environmental harms of industrial livestock systems and improve land stewardship. In limited local contexts, if grass-finished and feedlot grain–finished cattle could gain weight equally, this could alleviate the need for crops destined for feedlot. A recent estimate found that, globally, 34% of crops grown on recently converted natural ecosystems went to animal feed instead of feeding people directly. While grass-finished beef has a higher total water use, it can reduce water risk by shifting from irrigated feed crops for cattle feedlots to rain-fed pastures.

From a human health standpoint, grass-finished beef may contain slightly higher omega-3 fatty acids and vitamin E, but the differences are small and unlikely to meaningfully affect health outcomes. It is often slightly leaner, which can reduce total fat and saturated fat somewhat, but beef in general remains higher in fat than most food options, which increases the risk of heart disease. Within the broader category of red meat, it is still a Group 2A probable carcinogen, according to the World Health Organization. 

Another human health consideration is that grass finishing requires less antimicrobial use. Antibiotics and other antimicrobials are often used in large quantities in confined livestock systems, and cattle account for over half of antimicrobial use among cattle, chickens, and pigs. This use increased by 43% between 2010 and 2020, raising concerns about accelerating antimicrobial resistance and making infection treatments in humans less effective. This may be the strongest case for grass-finished beef, particularly within a global demand reduction scenario.

From an animal welfare perspective, pasture-based systems allow natural behaviors such as walking, socializing, and grazing freely. However, animals are still slaughtered at a young age (before 3 years old) relative to their natural lifespan of 20 years.

Why are we concerned?

Beef production is already the largest single land use globally and the most emissions-intensive food option. Shifting to grass-finished systems would further increase this footprint. Beef is inherently protein-inefficient, requiring large amounts of feed and land. While grass-finished systems were historically the norm, the rise of grain-finishing feedlots after the 1950s modestly improved efficiency by shortening cattle lifespans and reducing per-kilogram land use. Land is a key limiting factor in any expansion of grass-finished production. In the United States, pastureland could support only approximately 27% of current beef production under grass-finished systems. Maintaining current output would require roughly 30% more cattle and 270% more land and would result in a 43% increase in associated methane emissions.

Such land expansion would pose serious biodiversity loss risks. Animal-sourced foods are the leading driver of biodiversity and habitat loss globally. Ruminant meat is disproportionately responsible, causing extinction risks ~340 times higher than grains by mass and ~100 times higher than legumes both by mass and when adjusted for protein, according to a 2025 study.

Last, many government and commercial “grass-fed” certifications are not well enforced and often include cropland-grown forage, which still results in slower weight gain, more methane emissions, and often land carbon leakage. As a result, there are concerns about greenwashing as major fast-food chains market grass-fed beef as environmentally friendly.

While there will likely continue to be an appeal to consumers to choose grass-finished beef, it does not meaningfully change the environmental reality of producing it.

What is our assessment?

Based on our analysis, evidence suggests that insect farming offers minimal opportunities for emission reductions and more often replaces lower-emitting foods, while also facing high costs, low consumer acceptance, and several significant risks even at small industrial scales. For these reasons, insect farming is “Not Recommended” as a climate solution.

What is it?

This potential climate solution involves industrially farming insects, such as crickets, mealworms, and black soldier fly larvae, in controlled facilities to produce protein with lower resource use and lower climate impact for human consumption, livestock feed, or pet food. Currently, 2 billion people worldwide have a practice of eating insects for food, but industrial insect farming is a relatively new effort, even though 1 trillion insects are estimated to be farmed each year, with roughly 79–84 billion insects alive on farms at any given time globally. Most farmed insects are processed into powders, flours, and oils for snack foods, pet food, or animal feed. This solution does not include industrial insect farming for the production of honey, shellac, silk, or the use of insect waste as fertilizer.

Does it work?

Insects convert feed efficiently, grow quickly, can eat food waste, and require far less land than livestock, especially cattle, creating possible pathways for low-resource protein. However, recent analyses show highly variable and often high life cycle emissions, 4.2–25.8 kg CO₂‑eq /kg protein for insects as human food, with the upper end of this range approaching the lower bound for beef. The emissions intensity of insect-based livestock feeds varies from 2.8–11 kg CO₂‑eq /kg dry matter and is higher than for soybean meal (1.06–2.26 kg CO₂‑eq /kg dry matter). Insect proteins for pet food are 2–10 times more emissions-intensive than conventional pet foods that often use meat-industry by-products. Industrial farms in colder, fossil fuel–dependent regions show especially high footprints, with one United Kingdom industrial life cycle assessment (LCA) reporting emissions nearly 10 times those of a medium-sized farm in Thailand.

Why are we excited?

Insect farming has advantages over some widely produced foods, especially beef and pork, most notably that it requires far less land and feed. On average, insects require about 2 kg of feed to produce 1 kg of body mass, which is approximately 3–5 times more efficient than cattle and comparable to chickens. Many edible insects are also high in protein and provide micronutrients such as iron, zinc, and B vitamins. There is active research focused on reducing energy needs, breeding native species, and exploring the use of mixed human food waste as feed to better position insects as a potential climate solution.

Why are we concerned?

Overall, insect farming today has limited climate benefits, poor substitution of high-impact foods, significant local ecosystem risks, low consumer uptake, and high costs.

Most LCAs for insect farming are based on small-scale operations rather than industrial scales. Furthermore, common assumptions in insect farming research do not align with current industry practices, including overstated use of food waste as feed and reliance on outdated climate and price projections. While insect farming could plausibly displace some high-impact foods in the future, there is no current pathway for insects to replace pig and cattle products, a prerequisite for meaningful GHG emission reductions. Substituting insects for already low-impact foods such as flour or cereal ingredients, as is currently common, increases emissions. In addition, available insect products have limited sensory or textural similarities to meat compared with plant-based alternatives. Despite more than US$1 billion invested in scaling the sector, consumer acceptance remains low, with only 5% of production going to direct human consumption and 50% to the pet food market.

Industrial insect farming also carries serious risks. Research indicates that escapes of nonnative species disrupting local ecosystems are inevitable and will intensify as operations scale, potentially affecting other food production systems. Crowded, warm rearing environments can also act as disease-spreading vectors, even if insect farming’s direct zoonotic risk to humans is likely lower than that of intensive meat production. Over 80% of small insect farms supplying pet food have been found to contain parasites, with roughly a third carrying species capable of infecting humans or animals. Contamination risks persist when using mixed human food waste as insect feed due to potential pathogens and chemical residues, which regulatory frameworks are still working to assess.

Lastly, costs are a major barrier. The most comprehensive economic model to date finds that insects are unlikely to become a viable part of industrial animal feed in the near future. Insects are also not expected to reach price parity with meat before plant-based or even single-cell/fermentation-derived proteins. Claims of future cost competitiveness rely on assumptions of near-total utilization of food waste.

What is our assessment?

Based on our analysis, deploying electric irrigation pumps will reduce emissions but will not provide a globally significant climate impact (>0.1 Gt CO₂‑eq/yr ), even under high adoption scenarios, until electrical grid emissions decline further. Therefore, this potential climate solution is “Worthwhile.”

What is it? 

This solution reduces emissions from irrigation by replacing pumps powered by natural gas, diesel, propane, or gasoline with electric pumps. Irrigation is the practice of adding water to croplands or pastures to reduce crop water stress and increase productivity. Pumps are used on some irrigated croplands to extract groundwater, transport surface water, and pressurize water for application through sprinklers or drip irrigation systems. Electric pumps have much higher motor efficiencies (~88%) than fossil fuel pumps (~21–31%), so pump switching reduces the energy required to pump the same amount of water. The extent to which emissions are reduced depends on the emissions intensity of the electrical grid mix. Electric pumps reduce emissions when the emissions intensity of the grid is below ~0.75 kg CO₂‑eq /kWh, or when they are powered by on-site solar or wind energy. In some places, additional emissions reductions can be achieved through Improving Irrigation Water Use Efficiency.

Does it work?

The efficiency and emissions benefits of electric pumps over fossil fuel pumps are well established. On-farm pumping emissions, currently estimated at approximately 0.2 Gt CO₂‑eq/yr, could feasibly be eliminated if all fossil fuel pumps are replaced with electric pumps and electrical grid emissions reach net-zero, or if they are powered by on-farm solar or wind energy. However, the climate impact of electric pump adoption today would be much lower, as electricity generation still produces substantial emissions. Under current conditions, replacing a diesel pump with an electric pump will reduce emissions in most, but not all, places around the world.

Why are we excited?

Electric pumps can reliably reduce emissions, are already cost-competitive and widely used, and adoption is increasing. Irrigation is a major energy user, and its energy use is increasing as irrigated areas expand. These trends are expected to continue in the coming decades as climate change exacerbates heat and water stress and agricultural production intensifies in low- and middle-income countries. Coupled with ongoing reductions in electrical grid emissions intensity, the potential climate benefits of this solution are growing.

Electric pump adoption can also be geographically targeted, as just five countries (China, India, the United States, Pakistan, and Iran) account for almost 70% of irrigation energy use. Areas with high groundwater reliance can also be targeted, as groundwater pumping accounts for 89% of irrigation energy use.

Pump switching also provides additional benefits, such as lowering long-term energy costs for farmers and reducing air pollution from on-farm fossil fuel use. Access to the electrical grid is the primary technical barrier to electric pump adoption, but small-scale solar installations can be used where grid connectivity is limited. Powering pumps with on-site solar also eliminates operational emissions, reduces the load on the electrical grid, and insulates farmers from variability in energy costs. 

Why are we concerned?

The climate impacts of pump switching are highly dependent on the emissions factor of the electrical grid. A large share of the potential reduction in fossil fuel pumping is located in India and China, which currently have relatively high electrical grid emissions intensities. Under the current grid mix, we estimate that pump switching in these countries will result in only modest benefits or a small increase in emissions.

What is our assessment?

While Improve Aquaculture is unlikely to have a major climate impact, our assessment concludes that it is “Worthwhile” due to its ability to reduce pressure on wild fish stocks and terrestrial biomass, and because efficiency improvements made now are likely to scale into greater climate impact as the sector continues to expand.

What is it?

GHG emissions from aquaculture can be reduced by increasing the feed conversion efficiency of the cultured animals and decarbonizing on-farm energy use. Aquaculture – farming aquatic animals or plants for food or other purposes – is rapidly growing and now accounts for over half of the global production of aquatic animals, exceeding wild capture fisheries. Over 7% of human-consumed protein is aquaculture-produced. As this sector has grown, it has become increasingly reliant on external feed sources, with the share of non-fed aquaculture (e.g., bivalves that feed from the water column) dropping from nearly 40% in 2000 to 27% in 2022. Improving feed conversion ratios (FCR) – the amount of feed it takes to produce a given amount of biomass – can lower feed demand and reduce CO₂ and other GHG emissions tied to feed production and transport. FCRs can be improved by feed formulations that increase digestibility, genetic or breeding modifications to improve digestive efficiency in the cultured animal, species-specific feed formulations, and optimizing ration size and feeding frequency. At the same time, decarbonizing on-farm energy use can help reduce CO₂ emissions from common equipment, such as aerators and water pumps.

Does it work?

Interventions to improve feed and energy efficiency can reduce CO₂ emissions from aquaculture operations, although the potential achievable climate impact of these actions is currently unlikely to be globally meaningful (>0.1 Gt CO₂‑eq/yr ). Total annual emissions from aquaculture were estimated to be 0.26 Gt CO₂‑eq/yr in 2017, with nearly 60% of that attributed to feed production. Improving FCR is both plausible and effective, since it directly reduces the amount of food needed to cultivate fish and other species, thereby lowering emissions tied to feed production and transport. Between 1995 and 2007, improvements in FCR have ranged between 5 to 15% for a variety of species, including shrimp, salmon, carp, and tilapia.

Decarbonizing on-farm energy use can reduce equipment-related emissions, particularly in intensive systems that use energy for automated feeding systems, water temperature control, and circulation and aeration systems. In general, the potential impact of decarbonizing varies widely because on-farm energy use differs significantly across species and production systems. For instance, shrimp and prawn farming use nearly 20,000 MJ/t of live weight (LW), with over 75% from electricity, while bivalve production uses around 3,000 MJ/t of LW supplied largely by diesel.

Why are we excited?

Improving feed efficiency in aquaculture reduces demand for captured wild fish used in feed, reducing pressure on overfished stocks. It also lowers reliance on terrestrial biomass, such as soy, wheat, and rice, which come with additional land-use and emission costs. More efficient feeding can help reduce nutrient pollution, which can be responsible for high methane and nitrous oxide fluxes in some inland aquaculture systems. At the same time, decarbonizing on-farm energy use might ultimately lead to lower long-term operating costs and improved energy reliability.

Why are we concerned?

There are relatively few drawbacks associated with improving aquaculture. In the case of decarbonizing on-farm energy use, upfront costs could be high. For instance, installing solar panels or upgrading pumps can be financially challenging for small-scale operations. Energy use on farms can also vary throughout the day and night, which might not always align with renewable energy sources, like solar, without storage. While this solution focuses on reducing GHG emissions from existing aquaculture practices, it is important to recognize that aquaculture can be environmentally harmful and that impacts vary widely depending on how it is done, where it occurs, and which species are being cultivated.

What is our assessment?

Based on our analysis, vertical farms are not an effective climate solution. The tremendous energy use and embodied emissions of vertical farm operations outweigh any potential savings of reducing food miles or land expansion. Moreover, the ability of vertical farms to truly scale to be a meaningful part of the global food system is extremely limited. We therefore classify this as “Not Recommended” as an effective climate solution.

What is it?

Vertical farms are facilities that grow crops indoors, with multiple layers of plants stacked on top of each other, using artificial lights, large heating and cooling systems, humidity controls, water pumps, and complex building automation systems. In principle, vertical farms can dramatically shrink the land “footprint” of agriculture, and this could help reduce the need for agricultural land. Moreover, by growing crops closer to urban centers, vertical farms could potentially reduce “food miles” and the emissions related to food transport.

Does it work? 

The technology of growing some kinds of crops – especially greens and herbs – in indoor facilities is well developed, but there is no evidence to show that doing so can reduce GHG emissions compared to growing the same food on traditional farms. Theoretically, vertical farms could reduce emissions associated with agricultural land expansion and food transportation. However, the operation and construction of vertical farms require enormous amounts of energy and materials, all of which cause significant emissions. Vertical farms require artificial lighting (even with efficient LEDs, this is a considerable energy cost), heating, cooling, humidity control, air circulation, and water pumping – all of which require energy. Vertical farms could be powered by renewable sources; however, this is an inefficient method for reducing GHG emissions compared to using that renewable energy to replace fossil-fuel-powered electricity generation. Growing food closer to urban centers also does not meaningfully reduce emissions because emissions from “food miles” are only a small fraction of the life cycle emissions for most farmed foods. Recent research has found that the carbon footprint of lettuce grown in vertical farms can be 5.6 to 16.7 times greater than that of lettuce grown with traditional methods.

Why are we excited?

While vertical farms are not an effective strategy for reducing emissions, they may have some value for climate resilience and adaptation. Vertical farms offer a protected environment for crop growth and well-managed water use, and they can potentially shield plants from pests, diseases, and natural disasters. Moreover, the controlled environment can be adjusted to adapt to changing climate conditions, helping ensure continuous production and lowering the risks of crop loss.

Why are we concerned?

Vertical farms use enormous amounts of energy and material to grow a limited array of food, all at significant cost. That energy and material have a significant carbon emissions cost, no matter how efficient the technology becomes. On the whole, vertical farms appear to emit far more GHGs than traditional farms do. Moreover, vertical farms are expensive to build and operate, and are unlikely to play a major role in the world’s food system. At present, they are mainly used to grow high-priced greens, vegetables, herbs, and cannabis, which do not address the tremendous pressure points in the global food system to feed the world sustainably. There are also concerns about the future of the vertical farming business. While early efforts were funded by venture capital, vertical farming has struggled to become profitable, putting its future in doubt.
 

What is our assessment?

Based on our analysis, cultivated meat is promising in its ability to reduce emissions from meat production, but the impact on a large scale remains unclear. Based on our assessment, we will “Keep Watching” this potential solution.

What is it?

Cultivated meat (also called lab-grown or cultured meat) is a cellular agriculture product that, when used to replace meat from livestock, can reduce emissions. Cultivated meat is developed through bioengineering. Its production uses sample cells from an animal, in addition to a medium that supports cell growth in a bioreactor. Energy is required to produce the ingredients for the growth medium and to run the bioreactor (e.g., for temperature control, the mixing processes, aeration).

Does it work? 

Since the development of cultivated meat is still in its infancy, there is limited evidence on its emissions savings potential from large-scale production. Preliminary estimates differ by an order of magnitude, depending on the energy source used in the lab environment. Using fossil energy sources, emissions generated from the production of 1 kg of cultivated meat could reach 25 kg CO₂‑eq. If renewable energy is used, emissions could be about 2 kg CO₂‑eq/kg of cultivated meat. By comparison, producing a kilogram of beef from livestock generates 80–100 kilograms CO₂‑eq, on average. Almost half of those emissions from livestock beef are in the form of methane. Producing pig meat and poultry meat generates about 12 kg and 10 kg CO₂‑eq, respectively. Based on these estimates, cultivated meat could substantially reduce the emissions of beef. Compared to pork and chicken, however, its emissions depend on the source of energy used during production.

Why are we excited?

The cultivated meat industry is fairly new but growing rapidly. The first cell-cultivated meat product was developed in 2013. In 2024, there were 155 companies involved in the industry, located across six continents, mostly based in the United States, Israel, the United Kingdom, and Singapore. Agriculture is responsible for about 22% of global GHG emissions, and raising livestock, especially beef, is particularly emissions-intensive. Therefore, cultivated meat has great potential to reduce related emissions as demand for meat continues to grow across the world. Cultivated meat enables the production of a large amount of meat from a single stem cell. This means that far fewer animals will be needed for meat production. Cultivated meat is also more efficient at converting feed into meat than chickens, which reduces emissions associated with feed production and demand for land.

Why are we concerned?

Concerns about cultivated meat include scalability, cost, and consumer acceptance. Because cultivated meat is still an emerging area of food science, the cost of production may be prohibitive at a large scale. Although cell culture is routinely performed in industrial and academic labs, creating the culture medium for mass-market production at competitive prices will require innovations and significant cost reductions. There are still many unknowns about the commercial potential of cultivated meat and whether consumers will accept the products. In 2024, companies began to move from research labs to larger facilities to start producing meat for consumers. Several countries now allow the sale of cultivated meat. In the United States, about one-third of adults find the concept of cultivated meat appealing, and only about 17% would be likely to purchase it, according to a poll conducted on behalf of the Good Food Institute. However, even substituting a fraction of the beef consumed in the United States with cultivated meat could have an important impact on reducing emissions. Cultivated meat is a novel food and may require consumer education and producer transparency on production methods and safeguards in order to become more widely accepted.

What is our assessment?

Based on our analysis, improved ruminant breeding is one of the few promising solutions for reducing enteric methane production from the many millions of ruminants, including those managed on pasture and rangeland. However, it is not a climate solution that will yield quick results, nor is it ready for large-scale deployment at this time. Instead, it should be considered a wise mid- to long-term climate investment that we will “Keep Watching.”

What is it?

Selective breeding can produce ruminant livestock, such as cattle, goats, and sheep, that produce less enteric methane during digestion. Enteric methane represents 21% of humanity’s methane emissions, equivalent to 2.9 Gt CO₂‑eq/yr. Enteric methane is produced by microbes in the digestive system – primarily in the rumen, which is the first stomach compartment – and not by ruminants themselves, but its production is a symptom of inefficient digestion by the animal. Therefore, breeding for more efficient use of food by ruminants can reduce enteric methane emissions, while also potentially increasing meat and milk production. 

Does it work? 

Selective breeding of ruminants for reduced enteric methane production has been shown to be effective. One 10-year pilot breeding program resulted in a 12% methane reduction in animals born in the last generation. Other studies have reported emissions reductions ranging from 4 to 45 percent. The effect can be cumulative, with greater reductions in enteric methane production with every selected generation of ruminants. 

Why are we excited?

Despite their disproportionate climate impact, ruminant meat and dairy products are in high demand. Any strategy that can reduce methane emissions per kilogram of meat or milk could, if broadly adopted, yield globally meaningful reductions in methane emissions (>0.1 Gt CO₂‑eq per year). A major advantage of this selective breeding approach is that it is suitable for both confined and grazing ruminants. The vast majority of ruminant animals spend all or part of their lives on pasture or rangeland. In contrast, feed additives, which can also reduce enteric methane production, are only suitable for confined animals. In addition, there is some evidence that this solution could increase the meat and milk productivity of ruminants by capturing energy from feed and forages that would otherwise have been lost as enteric methane.

Why are we concerned?

Breeding ruminants to reduce enteric methane production is not a climate solution that will show quick results. It will require prolonged testing using expensive measurement equipment on thousands of animals and selective breeding for each breed of each ruminant livestock species over many generations. Some researchers say that decade-long breeding programs will be required. Other than a few research projects, however, the current adoption of selective breeding for methane reduction is very low. Furthermore, selective breeding focused only on methane reduction could result in the loss of other desirable traits, such as productivity or adaptation to local conditions and farming systems. It is also possible that reducing enteric methane emissions per kilogram of milk or meat may not necessarily reduce total emissions if, for example, farmers or ranchers increase their herd sizes. Finally, there is the concern that improved ruminant breeding could be used as a smokescreen to divert attention from the importance of reducing consumption of ruminant meat and milk products in the diets of wealthy countries and reducing food waste of ruminant products.

What is our assessment?

Based on our analysis, feed additives are a promising technology that could yield globally meaningful reductions in methane emissions. A few, including 3-NOP, are just on the threshold of commercial adoption and may be widely used by confined ruminant producers in the coming years. The current use of feed additives is low, and the effectiveness of most feed additive compounds is not well-documented. Consequently, wide-scale adoption is largely confined to confined livestock in high-income countries. Based on our assessment, we will “Keep Watching” this potential solution.

What is it?

Feed additives are a diverse group of natural and synthetic compounds that, when fed daily, can reduce enteric methane production in ruminant livestock, including cattle, sheep, and goats. Enteric methane from livestock is the source of 21% of humanity’s methane emissions, or 2.9 Gt CO₂‑eq/yr. Feed additives reduce enteric methane production by suppressing the activity of microbes in the digestive system. 3-NOP (3-nitrooxypropanol) is a synthetic that inhibits an enzyme involved in enteric methane production.

Does it work?

More than 170 different feed additives have been developed and tested so far, but only a few of them have been studied enough to offer predictable outcomes and proper doses. Methane reductions from these well-studied additives typically range from 10-30%. The feed additive 3-NOP, the first compound approved for commercial use, reduces enteric methane by an average of 32.5%. A second feed additive derived from active compounds found in Asparagopsis seaweed has shown promising results in some studies and has recently received regulatory approval in two countries. In addition, because different feed additives use different mechanisms to suppress enteric methane production, it’s possible that multiple additives can be used together to achieve greater methane reductions. The great majority of other additives are not yet ready for widespread adoption due to a lack of understanding of effectiveness, side effects on cattle and humans who consume milk from treated cattle, and other concerns.

Why are we excited?

Ruminants are a major source of methane emissions, yet ruminant meat and dairy products are in high demand. Therefore, any strategy that can reduce methane emissions per kilogram of meat or milk is potentially very valuable and, if broadly adopted, could yield globally meaningful reductions in methane emissions (>0.1 Gt CO₂‑eq per year). The feed additive 3-NOP, first approved for commercial use in two countries in 2021, is now legal in 55 countries. Research on other feed additives is active and generally well-supported with funding from philanthropic and investment sources. Although current use of feed additives is very low, successful research and pilot studies, increasing regulatory approvals, and strong positive interest from the livestock industry suggest that wider-scale adoption of this emissions reduction technology could occur quickly. In addition to potential emissions reduction benefits, some additives offer other benefits such as increased productivity and parasite control.

Why are we concerned?

Because they must be fed daily as a supplement to a concentrated feed, use of feed additives is limited to ruminants managed under confined conditions. Most of the billions of ruminant animals today are raised or managed in extensive grazing or pastoralist systems, often in small herds in remote areas. This makes use of feed additives infeasible, although some research is underway to develop methane-reducing compounds that could be added to water troughs instead of to feed. Feed additives are also costly. Though they may be cost-effective in terms of dollars per ton of CO₂‑eq reduced, the cost of additives themselves would likely be prohibitive for smallholders and pastoralists in low-income countries. These limitations mean that feed additives, as currently under development, are only suitable for a subset of total ruminant livestock – those that are raised in confinement systems in wealthy countries. The great majority of feed additives are not yet ready for widespread adoption due to a lack of understanding of effectiveness, side effects on cattle and humans who consume milk from treated cattle, and other concerns. There are also other challenges, including regulatory issues, public acceptance, and effects on livestock and human health. There is also concern that feed additives could be used to divert attention from the importance of reducing ruminant meat and milk products in the diets of wealthy countries and reducing food waste of ruminant products.