California's Cow-Manure Climate Credits Overstate Their Payoff, Researchers Say

A widely used California program pays dairies to turn cattle-manure methane into fuel, but a growing body of research says its carbon accounting overstates the climate benefit.

California's Cow-Manure Climate Credits Overstate Their Payoff, Researchers Say A widely used California program pays dairies to turn cattle-manure methane into fuel, but a growing body of research says its carbon accounting overstates the climate benefit. Aaron Rafferty July 02, 2026 Key Takeaways California pays dairy farmers to capture the methane from cattle manure and turn it into natural gas, rewarding them with Low Carbon Fuel Standard credits that oil companies buy. A growing body of research says the program's carbon math overstates the climate benefit by treating short-lived methane and long-lived carbon dioxide as if they cancel out. California extended parts of the program past 2050 in 2024, and a new air board proposal could send millions more dollars to dairies. California's marquee climate program has a manure problem. For years the state has paid dairy farmers, in California and beyond, to capture the methane that rises off manure lagoons and turn it into natural gas. Farmers who install anaerobic digesters earn Low Carbon Fuel Standard credits, which oil companies buy to meet the state's requirement to lower the carbon in their fuels. The subsidies are lucrative, and the program has grown fast. The trouble is the accounting, according to a MIT Technology Review analysis of a growing body of research. California treats methane as though it warms the planet about 25 times as much as carbon dioxide over 100 years. Methane is far more powerful in the near term, but it breaks down within a couple of decades, while carbon dioxide keeps heating the atmosphere for centuries. A system that credits capturing methane today, while permitting more carbon dioxide in its place, can trade a short-term win for near-permanent warming. The scale of a singl