A California Dairy Tried to Capture Its Methane, and It Worked

By Jules Bernstein

A giant, balloon-like tarp stretches over a lagoon of manure on a Central Valley dairy farm, concealing a quiet but remarkable transformation. Methane, a potent climate-warming gas, is being captured and cleaned instead of released into the atmosphere.

A new study by researchers at the University of California, Riverside shows the effectiveness of dairy digesters, which are manure ponds tightly sealed to capture and re-use the methane they produce. The study shows these systems can reduce atmospheric methane emissions by roughly 80%, a result that closely matches estimates California state officials have used in their climate planning.

The findings, published in Global Change Biology Bioenergy, come as California ramps up investment in methane control technologies to meet its goal of cutting emissions 40% below 2013 levels by the end of the decade. More than 130 of these systems are now operating across California dairies, but until now, their real-world performance hadn't been verified this rigorously.

"The digesters can leak, and they sometimes do," said Francesca Hopkins, a climate scientist at UCR who led the research. "But when the system is built well and managed carefully, the emissions really drop. That's what we saw here."