Livestock are responsible for 14.5 per cent of human-induced greenhouse gas emissions, with beef and dairy production accounting for the bulk of it, according to a 2013 United Nations report. Since the passage of its landmark global warming law in 2006, California has been reducing carbon emissions from cars, trucks, homes and factories, while boosting production of renewable energy. In the nation’s largest milk-producing state, the new law aims to reduce methane emissions from dairies and livestock operations to 40 percent below 2013 levels by 2030, McCarthy said. State officials are developing the regulations, which take effect in 2024. “We expect that this package … and everything we’re doing on climate, does show an effective model forward for others,” McCarthy said. Dairy farmers say the new regulations will drive up costs when they’re already struggling with five years of drought, low milk prices and rising labor costs. They’re also concerned about a newly signed law that will boost overtime pay for farmworkers.

“It just makes it more challenging. We’re continuing to lose dairies. Dairies are moving out of state to places where these costs don’t exist,” said Paul Sousa, director of environmental services for Western United Dairymen. The dairy industry could be forced to move production to states and countries with fewer regulations, leading to higher emissions globally, Sousa said. “We think it’s very foolish for the state of California to be taking this position,” said Rob Vandenheuvel, general manager for the Milk Producers Council. “A single state like California is not going to make a meaningful impact on the climate.” Regulators are looking for ways to reduce so-called enteric emissions methane produced by bovine digestive systems. That could eventually require changes to what cattle eat.