California dairy farmers are turning to an unlikely ally — red earthworms — to tackle the massive methane, nitrous oxide, and water pollution from cow manure. Third-generation farmer Anthony Agueda uses a vermifiltration system from Chilean company BioFiltro, where wood chips and crushed river rock form a biofilter that houses hundreds of thousands of worms. As the U.S. livestock industry faces mounting pressure to clean up its environmental mess, California has become a test bed, pouring over a billion dollars into solutions. Eight of these systems are already on U.S. dairies, with 16 more on the way. While it’s simple and cheaper than high-tech alternatives, researchers caution that more long-term data is needed to compare trade-offs and effectiveness. Why it matters: Vermifiltration could offer a scalable, low-cost way to slash agricultural emissions — a sector notoriously tough to decarbonize, and a key piece of the climate puzzle as global manure storage contributes around 10% of livestock’s climate impact.