California climate regulators yesterday approved rules to slash methane, refrigerants and soot particles that are among the most potent contributors to global warming.

The so-called short-lived climate pollutants (SLCPs), which spend less time in the atmosphere than carbon dioxide but trap far more heat during their lifetimes, accounted for 42 percent of California's greenhouse gas emissions in 2013. But they were left out of the state's first set of climate regulations.

The rules approved yesterday are aimed at meeting targets that the state Air Resources Board (ARB) first set in 2015: a 40 percent reduction in methane and fluorinated gases and a 50 percent reduction in non-forest black carbon emissions by 2030, below 2013 levels. The rules go into effect in January 2018.

Reductions will come through a number of new regulations, including eliminating food waste in landfills by 2025, requiring oil and natural gas producers to minimize leaks, banning the use of certain gases in new refrigerators and air conditioners, and grant programs to encourage replacement of wood-burning fireplaces with gas versions.

Among the biggest challenges will be to figure out how to reduce emissions from the state's 1.4 million dairy cows — the largest source of methane in the state, and the biggest source of dairy-related methane in the country. A bill from state Sen. Ricardo Lara (D) signed into law last year prohibits ARB from regulating methane from dairies and cattle farms until at least 2024. Until then, reductions will be voluntary and funded by various sources, including grants, pilot projects by utilities and the sale of credits under the state's low-carbon fuel standard (Climatewire, Dec. 9, 2016).

Dairy industry representatives urged the state to release grant money for dairy digesters, which siphon methane from lagoons of manure and use it to power generators. "Adopting the plan's the easy part," said Michael Boccadoro, executive director of the industry trade group Dairy Cares, which represents 98 percent of the state's milk producers. "Figuring out how we together get to the reductions the state is looking for becomes the hard part."

Environmental advocates largely praised the rules, but those representing communities dealing with conventional air pollution said more needs to be done to address dairy pollution.

"We're producing all of this methane in-state when it's not necessary," said Brent Newell, an attorney with the Center on Race, Poverty and the Environment. "Imagine if we had a robust coal-fired power plant industry. We wouldn't continue with that coal-fired power plant industry just because it's in California. ... We need to decarbonize what we eat, as well."

Lara said he would introduce a bill next week to incentivize replacement of wood-burning stoves, which contribute to black carbon. Local air officials welcomed the news, pointing out there are roughly 350,000 stoves in the state that need to be replaced.

"It's going to be a tremendous lift to get to where we need to go," said Alan Abbs, executive director of the California Air Pollution Control Officers Association.

Reprinted from Climatewire with permission from E&E News. E&E provides daily coverage of essential energy and environmental news at