California has become a US environmental trendsetter
Regulators in California have adopted plans to put into effect the country's most comprehensive global warming law to cut greenhouse gas emissions.
It includes targets for emissions cuts from cars, refineries, buildings and landfills.
The California Air Resources Board approved the plan to help the state meet goals set out in the landmark Global Warming Solutions Act of 2006.
The law mandates that the state cut emissions to 1990 levels by 2020.
The new measures include plans to create a carbon-credit market and targets for renewable energy generation.
Republican Governor Arnold Schwarzenegger, who backed the 2006 act, said California was providing a roadmap for the rest of the country.
"Today is the day we help unleash the full force of California's innovation and technology for a healthier planet, a stronger and more robust economy and a safer and more secure energy future," he said.
Mr Schwarzenegger has said he believes the plan will be a spur to the state's economy.
However, it has faced opposition from fellow Republicans, small businesses and industry, which said it would cost too much to implement and could lead to job loses.
California claims it faces dangerous consequences from global warming by the mid-century, including water shortages due to its melting mountain snowpack.