For example, he said, counties can cut down on future carbon emissions by placing high-density housing next to offices and public transit centers, thus reducing commuter car trips.
"If the ice in Greenland just part of it melts at the rate it's going, it won't be too long until Oakland's and San Francisco's airports are under water," Brown told more than 500 leaders gathered in his hometown of Oakland at the annual California State Association of Counties conference.
"This threat is irreversible and will not be unwound with just a few years of policy change. As (county) supervisors in charge of land use, you have a lot of opportunities to get involved in this challenge," he said.
And if they don't, Brown said, he can sue local governments to ensure they are complying with the state's landmark environmental law, the California Environmental Quality Act.
He's done it before. Earlier this year, Brown sued San Bernardino County, alleging it did not adequately consider greenhouse gas emissions when updating its general plan. The two parties settled the suit this summer when the county agreed to track its emissions and set a target to reduce them.
Brown went after Contra Costa County supervisors as well, calling or meeting with each personally and urging them to only approve an oil refinery expansion project in Rodeo after ConocoPhillips agreed to offset extra emissions.
A legal showdown was avoided in September when the company vowed to pay $10 million to plant trees, scrap heavy-polluting cars, restore the San Pablo wetlands and work on other environmental projects.
Brown told county leaders in the audience to work with his office to avoid or reduce significant harm to the environment when planning developments.
"We have a duty and a right to respond to every environmental impact report," he said. "If you don't talk about greenhouses gases, we are going to send you a letter. If you still don't talk about greenhouse gases, you might get sued."
Brown spoke during a conference luncheon along with Gov. Arnold Schwarzenegger, who also talked about the state's environmental challenges.
The governor encouraged county leaders to endorse a $10 billion water infrastructure bond, which he continues to negotiate with Democratic legislative leaders to place on the February ballot. The bond
money would help pay to restore the Delta, build additional water storage and capture water from storms and snowmelt run-off.
"Our snowpack is declining, meaning more flooding in winter and less drinking water in the summer," Schwarzenegger said. "We have not added a major state reservoir in more than 30 years, even as our population was booming from 20 million to 37 million. California is facing a serious water crisis."