Sacramento, CA (AP) - With little time and deep-pocketed opposition from oil interests, Gov. Jerry Brown and legislative Democrats were forced on Wednesday to retreat from their ambitious proposal to address climate change by dropping a key mandate to cut California's petroleum use by 50 percent.

Amid the political setback, they vowed to intensify their fight to reduce greenhouse gas emissions through other means and pledged to continue to champion the environmental cause for the good of future generations. Brown, a Democrat who has made climate change the centerpiece of his final term, said state regulators will announce toughened reporting rules on low-carbon fuel standards as early as next week.

"I'd say oil has won the skirmish, but they've lost the bigger battle," Brown said. "Because I'm more determined than ever to make our regulatory regime work for the people of California — cleaning up the air, reducing the petroleum and creating the green jobs that are going to put hundreds of thousands of people to work."

Brown and Senate President Pro Tem Kevin de Leon, a Los Angeles Democrat, had pushed a far-reaching proposal to cut petroleum use by half, boost renewable-electricity use to 50 percent and double energy efficiency in existing buildings. They dropped the mandate to cut oil use from the proposal, SB350, amid fierce opposition from business groups and oil companies that sought to strip a powerful state regulatory board from setting vehicle emissions and fuel standards.

Many Democrats — including moderates and those representing less wealthy districts — were concerned that the petroleum mandate would hurt California's economy and working-class residents. They wanted greater oversight of the air board that has been in charge of implementing California's ambitious greenhouse gas emissions law signed by Gov. Arnold Schwarzenegger, a Republican.

"Today's announcement was an acknowledgement that California's energy future, economic competitiveness, and environment are inextricably linked," said Catherine Reheis-Boyd, president of the Western States Petroleum Association. "Californians are best served by inclusive energy policy and by a legislative body that retains authority on issues so critically important to jobs, communities and our way of life."

Brown and legislative leaders now plan to move forward with the remaining two components to increase renewable energy and improve energy efficiency in buildings.

Assembly Speaker Toni Atkins, D-San Diego, whose members resisted the petroleum piece, said she felt confident the bill would pass. Lawmakers have just two full days remaining for bills to emerge from the current legislative session.

De Leon said that despite their best efforts, supporters could not overcome "the silly season scare tactics" of the oil industry. "We couldn't cut through the multibillion-dollar smoke screen created by big oil with a bottomless war chest," he said.

Brown said the primary sticking points for moderate Democrats in the state Assembly concerned the California Air Resources Board, an unelected body with broad power to set vehicle emissions and fuel standards to decide how the state will reduce oil use.

The governor said opponents agreed to pass the legislation if he agreed to dramatically scale back its power, but he refused.