In California, polling shows that most people think climate change is already having an effect. But scientists are concerned that politicians are not acting fast enough. Now a UC Berkeley professor is urging other scientists to speak out.

Shasta Lake is the largest reservoir in California, and government officials are completing plans to make it even larger by raising the height of the dam. But the expansion has sparked intense debates among local residents, Central Valley farmers, environmentalists, tribal groups and developers.

Valero wants to start using trains to bring crude oil to its Bay Area refinery. But the project is raising concerns about congestion, safety and air pollution in the East Bay city of Benicia – and the connection it may have to Canada’s controversial tar sands.

In some alcoholics, the act of overriding one's better judgment to have another drink can be traced to a specific network in the brain. The question is, can you make it do something else?

When you're cooking dinner, the air inside your kitchen can sometimes be just as harmful as smog. Range hoods are designed to capture cooking fumes, but even some expensive models aren’t very effective. Researchers are trying to fix that.

Though engineers can purify sewage water to make it cleaner than what’s coming out of your tap, there's a bigger challenge: convincing people to drink it.

After controversy over a threatened species delayed several large solar projects, state officials are trying to broker an agreement between conservation groups and solar companies on a path forward for renewable energy.

Proposition 65 is enforced by, among others, a small and little-known subculture of "private enforcers," and their attorneys who profit from settlements with businesses found to be in violation of the law. Critics call it a "cottage industry;" others say it's an efficient way to protect consumers from toxic chemicals.

Proposition 65 was passed by voters in order to reduce Californian's exposure to toxic chemicals. Now there's an effort in Sacramento to revise the law, amid charges that it's prompted a flood of frivolous lawsuits that make millions of dollars for a select few and cause undue headaches for thousands of California businesses.

A proposal to cut 100,000 eucalyptus trees or more has stirred up controversy, and now, a long-running battle over the plan is coming to a head.