California might finally be cracking down on cow farts

The state passed a bill to regulate “super pollutants” like black carbon and methane.

A pair of dairy cows in San Joaquin County, CA. CREDIT: AP PHOTO/RICH PEDRONCELLI, FILE
A pair of dairy cows in San Joaquin County, CA. CREDIT: AP PHOTO/RICH PEDRONCELLI, FILE

It’s been a busy couple of weeks for climate action in California, and the good news for climate activists keeps rolling in: On Monday, Gov. Jerry Brown (D) signed a bill restricting the emission of ‘super pollutants’ like black carbon and methane in an effort to fight climate change.

“Cutting black carbon and other super pollutants is the critical next step in our program to combat climate change,” Brown said at a signing ceremony in Long Beach. “This bill curbs these dangerous pollutants and thereby protects public health and slows climate change.”

Super pollutants — like black carbon or methane — are short-lived in the atmosphere, but pack a potent warming punch. Methane, for instance, is 86 times more powerful than carbon dioxide over a 20-year period. And hydrofluorocarbons (HFCs), which are also restricted by the new bill, can be tens of thousands of times more effective, over the short term, in trapping heat than carbon dioxide.

The bill seeks to severely limit these short-lived pollutants, aiming to cut black carbon in half, compared to 2013 levels, by 2030, and reducing methane and HFCs by 40 percent over the same time period.


In addition to fueling climate change, these super pollutants can have an immediate impact on public health. Black carbon, which is particulate matter left over from the burning of fossil fuels and can be found in things like diesel exhaust, has been linked to health problems like heart attacks, strokes, cancer, and developmental effects in children.

“This bill represents a unique opportunity to balance our global vision for the future with a much more local and immediate perspective,” California State Senator Ricardo Lara (D) said at the signing ceremony. “With these bold and ambitious goals, we’ll continue to set the standard for climate policy worldwide. And most importantly, those changes will be felt right here in California and reflected in the health of our children and future generations to come.”

California began considering limits on super pollutants in 2014, when the State Assembly directed the Air Resources Board to develop a plan for cutting super pollutants across the state. The plan, however, has come under fire from environmental groups, which argue that it relies too heavily on voluntary measures to reduce industry pollution.

The dairy industry, for example, accounts for 5 percent of the state’s total greenhouse gas emissions — California has both the most dairy cows in the United States and the highest aggregated dairy methane emissions, according to the Air Resources Board. But the state’s 2006 Global Warming Solution’s Act effectively exempted agriculture from regulations — allowing the sector to emit methane unfettered for years.


This bill — along with the 2014 bill directing the Air Resources Board to begin regulating short-lived pollutants — might change that. But so far, the proposed strategy for combating the pollutants leans heavily on voluntary measures, like incentivizing the installation of anaerobic digesters on dairy farms across the state. And while that might help staunch some methane emissions, anaerobic digesters come with their own set of pollution issues, from potentially noxious compounds in the biogas itself to the local air pollution created from the motors that run the digesters.

The new legislation sets aside $50 million for the state’s dairy farmers, which could help them finance digesters for their operations. But the bill also gives the Air Resources Board the authority to regulate any industry that isn’t achieving deep enough reductions through incentivized measures. The Air Resources Board will have until the beginning of 2018 to decide how the reduction goals will be met.