Digesters usually cut methane at California dairies ^{CEFR B1}

Dairy manure digesters seal ponds and channel methane so it can be used as fuel. Methane is shorter lived than carbon dioxide but about 80 times more powerful at trapping heat, so even small releases have a large climate effect.

Lead author Alyssa Valdez and her team at the University of California, Riverside used eight years of satellite and airborne data to track emissions at 98 dairies before, during and after digester installation. They found the number of strong methane plumes declined after digesters were installed, which suggests the systems are effective overall. This result builds on an earlier study that showed a single well-managed digester can cut methane by as much as 80%.

The researchers also recorded occasional extreme leaks around 1,000 kilograms per hourand emission spikes during construction and installation. Aircraft measurements helped locate concentrated plumes, while satellites allowed long-term tracking across many sites. The study notes these methods miss more diffuse releases from lagoons and fields, so they work best when combined with on-site measurements. California already has hundreds of digesters operating or planned, and the team calls for careful monitoring to ensure real climate benefits.