The agreement comes three weeks after the governor ordered new targets for reducing greenhouse gas emissions in California. He's also been pushing for more renewable energy, lower gasoline consumption and better efficiency in older buildings.
Even as Brown works to set a high bar for tackling climate change in California, he's been keenly aware of the need for other states and countries to take similar action to have a significant impact on the environment.
"We're not an island to ourselves," he said last month in Los Angeles.
The Brown administration has also been working with Oregon, Washington, British Columbia, Quebec and other places.
The governor plans to attend an international summit on climate change in Paris later this year, where world leaders hope to reach a new treaty.
Getting other leaders to follow California's lead is a key test, said Robert Stavins, director of the Harvard Environmental Economics Program.
"You don't want to be the general leading the charge across the field, then you look behind you and nobody is there," he said.