Calif., top dairy state, has law to cut methane emissions from cow flatulence, other sources

Environmental Protection Agency graphic

California Gov. Jerry Brown on Monday signed a bill intended to cut methane emissions from sources such as cow flatulence, in the nation's top dairy state, Sharon Bernstein reports for Reuters. Under the bill "the state will cut emissions of methane from dairy cows and other animals by 40 percent and black carbon from diesel trucks and other sources by 50 percent. The bill also mandates the state to reduce emissions of fluorinated gases, or hydrofluorocarbons used in refrigeration."

Enteric fermentation—methane that livestock produce as part of their digestion—accounts for almost one third of the emissions from the agriculture sector, while manure management accounts for about 14 percent of the total greenhouse gas emissions from the sector, Jeremy White reported in August for The Sacramento Bee. California's dairy industry produces 20 percent of the country's milk.

Brown, a Democrat, has signed several bills aimed at climate change in recent weeks, "including one that by 2030 will mandate an overall reduction of greenhouse-gas emissions to 40 percent below the level released in 1990," Bernstein writes. "In addition to black carbon, which comes from trucks as well as the burning of organic material and other sources, the bill also requires reductions in hydrofluorocarbons, used in refrigeration and to power aerosol products."