Greener Beef
Over the past few decades, society has begun to push back against global warming, slashing CO2 emissions, and implementing green policies. But while CO2 has remained a primary focus, other greenhouse gases like methane have been forgotten. Methane is primarily released as a result of agriculture, more specifically, cattle. These large ruminants release over 30% of all global methane, impacting the environment beyond their already enormous consumption needs. However, a recent discovery may change this problem forever. By supplementing bovine diets with a small amount of seaweed, scientists have shown an astonishing 82% methane reduction! While only being demonstrated at a small scale, this slight diet change could be the next step towards sustainable cattle farming.
How do Greenhouse Gases Affect the Environment?
Before we discuss how seaweed reduces methane emissions, it is essential to understand how greenhouse gases, like methane, cause global warming. Greenhouse gases heat up the atmosphere by trapping heat from the sun, warming the planet, and driving climate change. We can see the impacts of the greenhouse effect in the increasingly erratic weather patterns across the globe, loss of polar and glacial ice, and rising sea level. Carbon dioxide is the most well-known greenhouse gas because it is released in large quantities from burning fossil fuels, cement production, and deforestation. It remains in the atmosphere for centuries, causing long-term warming. On the other hand, methane is much more potent in the short term, over 25 times stronger than CO₂ at trapping heat, but it persists for a shorter time in the atmosphere.
How does Seaweed help solve this issue?
A big share of globally produced methane comes from agriculture, especially cows. When cattle digest their food, microbes in their stomachs (the rumen) break down grasses and release methane through a process called enteric fermentation. Researchers have found that a red seaweed called Asparagopsis taxiformis can sharply cut methane from cattle. In a 2021 study, Roque et al. showed that adding a small amount of this seaweed to cow feed reduced methane emissions by more than 80%, without affecting animal health or growth. This is thanks to a natural compound called bromoform found in this seaweed. It disrupts the enzymes that methane-producing microbes in the rumen rely on, and with that process blocked, cows produce far less methane.
How would this be implemented?
The truth is that scaling this project will be challenging to say the least. Growing enough Asparagopsis for millions of cattle means expanding sustainable seaweed farming will be quite a challenge. Scaling production in a sustainable manner and evaluating the impact that oceanic monocropping may have must be considered. There are also open questions about long-term effects on animals and whether the methane cuts last. Still, the potential is huge. If global cattle emissions fell by 82%, as lab studies suggest, annual global warming could be reduced by 5-8%, buying us the essential time we need to solve climate change. While feeding cattle seaweed won’t solve climate change, it is an important discovery on a journey to greener beef.
Breanna M. Roque, Marielena Venegas, Robert D. Kinley, Rocky de Nys, Toni L. Duarte, Xiang Yang, Ermias Kebreab. Red seaweed (Asparagopsis taxiformis) supplementation reduces enteric methane by over 80 percent in beef steers. PLOS ONE, 2021; 16 (3): e0247820 DOI: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247820
Shan, Yuli, et al. “Global Methane Footprints Growth and Drivers 1990–2023.” Nature Communications, vol. 16, no. 2147, 2025, pp. 1–12. Nature Publishing Group, https://doi.org/10.1038/s41467-025-63383-5
Lau, Bon. “What Are the Major Sources of Methane in the Atmosphere?” Earth.Org, 12 Dec. 2022, https://earth.org/sources-of-methane-in-the-atmosphere/
Greener Grazing. (n.d.). Greenergrazing.org. https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.greenergrazing.org%2F&psig=AOvVaw0I72QLNh8Tnmo0xVwo0365&ust=1760658157935000&source=images&cd=vfe&opi=89978449&ved=0CBYQjRxqFwoTCNjuq_Owp5ADFQAAAAAdAAAAABAE