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Watch how Farmers turn to seaweed in attempt to reduce methane emissions from livestock here
As the world searches for practical ways to reduce greenhouse gas emissions, one unlikely solution is making waves in agriculture: feeding cows seaweed.
It may sound unusual, but researchers around the world are finding that adding tiny amounts of a specific red seaweed to cattle feed could dramatically reduce methane emissions without affecting animal health, milk quality, or productivity.
Cows naturally produce methane during digestion through a process called enteric fermentation.
Unlike carbon dioxide, methane is an extremely powerful greenhouse gas. Over a 20-year period, it traps around 80 times more heat than carbon dioxide, making it one of the biggest contributors to short-term global warming.
Most of this methane doesn't come from flatulence, as many people assume. Instead, it is released primarily through the cow's burps.
Globally, livestock accounts for a significant share of human-related methane emissions, making it an important area for climate innovation.
Scientists have been studying a red seaweed called Asparagopsis taxiformis.
When included in a cow's diet at less than 0.5% of total feed, the results have been remarkable.
Trials have shown:
Researchers at the University of California, Davis continue to study the additive, with some scientific literature reporting methane reductions approaching 98% under certain controlled conditions.
Inside a cow's stomach lives an enormous community of microbes that help digest grass and other plant material.
During digestion, these microbes naturally produce hydrogen and carbon dioxide. Special microorganisms known as methanogens then convert these gases into methane.
The active ingredient in Asparagopsis seaweed is a natural compound called bromoform.
Bromoform temporarily interrupts the enzyme methanogens need to produce methane, dramatically reducing emissions while allowing digestion to continue normally.
One of the biggest questions for farmers is whether adding seaweed changes food quality.
Early commercial trials suggest encouraging results.
Researchers observed:
This means farmers may be able to reduce emissions without sacrificing production.
Several companies are now working to grow enough seaweed to support commercial livestock farming.
One example featured in the PBS NewsHour report is Blue Ocean Barns, which is scaling seaweed production using specialised cultivation systems in Mexico after early research in California.
The challenge is no longer proving the science. It's producing enough seaweed efficiently and economically to supply millions of cattle worldwide.
Seaweed isn't a silver bullet for climate change, but it represents one of the most promising methane-reduction technologies currently being developed for agriculture.
Combined with improved grazing practices, manure management, regenerative farming, and advances in livestock genetics, seaweed supplements could become an important tool in reducing agriculture's environmental footprint.
Despite the impressive results, several hurdles remain before widespread adoption becomes reality:
Researchers continue to work on solving these challenges while conducting long-term studies on effectiveness and sustainability.
Reducing methane emissions from livestock has become one of the fastest opportunities to slow near-term climate warming.
Remarkably, achieving this may require nothing more than adding a tiny amount of seaweed to a cow's daily feed.
While more research and large-scale production are still needed, the evidence so far suggests that one of the ocean's simplest plants could play an important role in creating a more sustainable future for farming.
