California has a dairy digesters program that’s wildly popular with farmers. The subsidies are extremely lucrative. There’s just one problem — the carbon math doesn’t add up.
Here’s the system: State regulations require transportation fuel companies to lower their carbon dioxide levels over time. If they can’t, they buy credits from other parties that cut fuel emissions — including cattle farmers.
Dairies usually spray manure into open lagoons. Microbes eat the organic matter and produce methane. Anaerobic digesters capture that biogas instead, convert it to natural gas, and inject it into pipelines. Petroleum companies then pay farmers for LCFS credits instead of cleaning up their own fuel.
Sounds good, right? Not exactly.
California assumes methane has about 25 times the warming effect of CO2 over 100 years. But that’s not how the atmosphere works. Methane is super powerful but breaks down fast — within a couple of decades. CO2 builds up cumulatively and keeps heating the planet for millennia.
So the state created a system that reduces short-term warming by trading it for permanent warming. Any methane captured today would have caused powerful warming if released, but by 2050 that effect fades. The CO2 released instead keeps cooking the planet for centuries.
UC Berkeley economist Aaron Smith calculated the distortion: adding one average biogas vehicle generates enough credits to cover 26 gas-powered cars.
Despite the concerns, California extended parts of the program beyond 2050. A new proposal could send even more money to dairy farmers while easing restrictions on major polluters.
The core problem: we need to clean up every sector completely. Swapping pollution between industries is just rearranging deck chairs.
