SACRAMENTO, Calif. — Gov. Jerry Brown has made climate change the centerpiece of his final tenure by laying out the most aggressive benchmark in North America, which would reduce California’s carbon footprint and boost the state’s renewable energy use to 50 percent in 15 years.

Securing legislation requiring that standard in the world’s eighth-largest economy would be a timely win for Brown before international leaders meet in Paris in November for the United Nations climate change conference. Brown is likely to attend the conference, but he has not said so officially.

But first, the Democratic governor has to break through a logjam in his own party in the final week of the legislative session.

Many Assembly Democrats — including moderates and those representing less wealthy districts — are concerned that the ambitious proposal to cut petroleum use by half, boost renewable electricity use to 50 percent and double energy efficiency in existing buildings will hurt California’s economy and working-class residents.

An oil industry-funded group, the California Driver’s Alliance, is running what climate law proponents call “fear-mongering” ads suggesting the bill will raise gas prices and even result in rationing, harkening back to gas lines during the oil crisis of the 1970s.

Lobbying has intensified on both fronts. Billionaire environmental activist Tom Steyer and Oscar-winning actress Halle Berry are making personal appeals urging undecided lawmakers to vote for the bill. They are joined by President Barack Obama, California U.S. Sens. Dianne Feinstein and Barbara Boxer and a long list of fellow Democrats.

So far, the Brown administration and legislative leaders have shared little publicly as backroom negotiations come down to Friday’s deadline to consider bills.

“I think the historic weight of this measure is starting to be felt,” said Senate President Pro Tem Kevin de Leon, D-Los Angeles, during a news conference Tuesday with local bishops, who cited Pope Francis’ encyclical on the environment as a call to action.

“I think at the end of the day that many members on the Assembly side will clearly look at the short- and long-term implications of health and to the economy of California and will do the right thing,” said de Leon, who is carrying Brown’s proposal.

Californians share Brown’s environmental concerns and a majority supports his call for tougher standards.

A July poll by the Public Policy Institute of California found 79 percent of residents agree global warming is either a very serious or somewhat serious threat to quality of life.

One of the main sticking points for lawmakers reluctant to tighten climate change rules concerns 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.

Some moderate Democrats want the Legislature to approve board regulations, but de Leon has said he is unwilling to strip the agency’s power. Sen. Fran Pavley, D-Agoura Hills, who is carrying a companion bill to extend California’s current emission-reduction targets to 2050, said she would add a requirement for the board to conduct a cost-benefit analysis of policies for lawmakers to review.