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Cow Burps Have a Big Climate Impact. Solving That is Harder than You’d Think

6 minute read
McFadden, PhD, is an associate professor of dairy cattle biology in the Department of Animal Science at Cornell University. He studies dairy cattle nutrition and the efficiency of milk production including enteric methane production

To slow global warming within the decade, the fastest (and perhaps only) way is to curb emissions of methane—one of the most potent of greenhouse gases with more than 80 times the warming potential of carbon dioxide over a 20-year period. The Global Methane Pledge, launched in 2021, set a target to reduce global methane emissions 30% by 2030, relative to 2020 levels, while enhancing public health and agricultural productivity. It is a goal that can’t be achieved without urgent and widespread reductions in livestock methane emissions.

Agriculture contributes about 40% of total global methane emissions—the bulk of which is belched from grazing livestock due to digestion of dietary carbohydrates. This methane from livestock is part of a natural carbon cycle, but reducing livestock methane using feed additives is key to lowering global methane emissions, as well as enhancing the conversion of dietary energy to meat or milk production without compromising the animal’s health.

Read More: Researchers Reveal the Worst Methane Super-Emitters in the U.S.

In support of the Global Methane Hub’s work to develop a global research accelerator to reduce livestock methane, I engaged in discussions with 20 animal scientists in 11 countries to identify barriers for the acceleration of the discovery and adoption of methane-reducing feed additives. Here are the biggest challenges we identified:

No silver bullet for farm systems, and too much uncertainty

Currently, there is no scalable technology today that provides robust and consistent reductions in enteric methane emissions from the wide array of farm systems that exist in the world. We cannot ask farmers to lower methane emissions without providing them effective, safe, and profitable solutions.

Studies of feed additive supplementation in cattle that span months—even years—are needed to confirm the persistency of methane reduction and animal safety. Diet, environment, management, animal genetics, and their microbiome are expected to uniquely influence the degree of methane reduction for feed additives. However, we have a limited understanding of how these factors impact the short and long-term efficacy of feed additives to inhibit methane production by cows.

Feeding cows seaweed is one solution being discussed, but it has not been properly evaluated by scientists and is plagued by cultivation requirements for broad adoption. Feeding bromoform, the active ingredient in seaweed, could be a potential solution but we must carefully examine its efficacy over time, as well as its toxicity.

Little consideration has also been given to alternative ways of actually delivering methane-reducing feed additives to cattle. Although the common approach in conventional cattle systems is to provide a feed additive in a cow’s diet, this approach may not be suitable for ruminants that graze pasture. Providing the feed additive in water or as slow release capsule provided directly to the cow’s stomach may be more suitable for this farming practice. What’s more, we must also adequately explore early life interventions for cattle, such as dietary feeding strategies or vaccines, which lower cattle’s methane production into adulthood and can minimize the need to provide feed additives daily throughout life.

We also cannot underemphasize the importance for research that evaluates the net impact of feed additives on greenhouse gas emissions, nitrogen, and phosphorus excretion in the environment, efficiency of production, as well as the presence of any residues in meat or milk that are of a potential concern to human health.

Farmers in developing nations face high barriers to adopting methane mitigating tech

We cannot achieve a 30% reduction in global methane emissions by 2030 if we ignore subsistence and smallholder farmers in developing nations. They are integral to the agricultural landscape because they provide nutrition, traction, fertilizer, and prosperity to low socioeconomic communities.

Without incentives or government mandates, the cost for purchasing a feed additive, as well as the lack of distribution and absence of prioritizing the adoption of methane-mitigating technologies, are bottlenecks to wide adoption in these farming systems.

In addition, the efficiency of animal production in developing countries, such as those in South Asia or sub-Saharan Africa, is drastically lower than that of the United States or Europe. The cause is poor animal genetics and management, and inadequate animal nutrition to meet the requirements for meat or milk production. Therefore, methane intensity per unit of animal-sourced food is far greater.

In a 2011 study in Environmental Science and Pollution Research, the emission rate was 0.92 and 1.98 in the USA and India, respectively. It is was also estimated that India contributed the highest percentage of global dairy-related CO2-equivalent emissions because milk per animal is low and the population of cattle and buffaloes is high.

To achieve the 30% reduction in global methane emissions by 2030, we must enhance the efficiency of meat and milk production in developing nations but do so without compromising the livelihoods of farmers or their communities. Such possibilities include enhanced nutrient balancing, improved fodder crop production and quality, accelerated use of crossbreeding and reproductive technologies such as in vitro-fertilization and sexed semen, improved veterinary medicine to reduce disease, and enhanced farmer education.

There is a massive investment gap in methane mitigation solutions

Speaking at COP27 in Nov. 2022, U.S. Deputy Special Envoy for Climate, Rick Duke, said that less than 2% of current climate finance is used to develop methane mitigation solutions. Because of this poor investment, he emphasized that methane emissions are expected to increase, not decrease, by 2030 under a status-quo scenario.

Investment and reform are needed for the regulatory registration of feed additives that reduce methane production. In the U.S., there is no pipeline to accelerate the approval of methane-reducing feed additives proven safe and effective by the Food and Drug Administration. The current approach is that products seek approval from the Food and Drug Administration’s Center for Veterinary Medicine via the New Animal Drug Application (NADA) process, which is oftentimes intensive and lengthy due to its stringent clinical trial requirements. Teams at Cornell University, UC Davis, Environmental Defense Fund, and Global Research Alliance are working to develop standards that define efficacy of feed additives as means to improve the regulatory process and accelerate entry of these technologies onto the marketplace using a streamlined approach.

At the same time, many university facilities in the U.S. that study cattle have been decommissioned or scaled down. Equipment for absolute quantification of greenhouse gasses is limited. Analytical tools to study feed chemistry and metabolism of the animal are defunct or underdeveloped. University faculty positions have gone unfilled to weaken expertise. Not to mention, federal funding for feed additive research is dramatically insufficient considering the strict requirement for intensive studies that confirm consistent methane reduction and safety. The issue is worse in developing countries.

Collectively, these barriers need to be addressed if we have any hope of lowering global methane emissions by 2030. International engagement for the discovery, approval, and adoption of regional solutions that reduce methane from livestock—while also improving human health, food security, and farmer prosperity—must be prioritized.

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