With only a few days left in the current session of the California legislature, an aggressive political and public relations fight between the oil industry and top lawmakers over climate change legislation is moving into a final round.

At stake is the passage of far-reaching environmental bills that would fundamentally alter the way the state does business and deals with planet-warming pollution – but would likely also change the way everyday Californians travel, live and consume.

The proposed laws represent a Democratic push to curb emissions and promote clean energy that specifically targets “mobile” pollution from cars and other gas-burning vehicles.

Petroleum companies are warning that the lack of specific plans in the policies could lead to gas rationing, surcharges on minivans and trucks, and even government-imposed fines on driving habits, monitored via a vehicle’s onboard computer – big brother in the passenger seat.

Democratic leaders are calling these warnings “doomsday scenarios” that won’t happen.

One of the two main bills, SB 350, calls for a 50% reduction in petroleum use by vehicles by 2030, the equivalent of removing 36m cars and trucks from the road.

It also calls for 50% of the state’s electricity supply to be derived from renewable resources by that date, and 50% better energy efficiency in buildings through retrofits and upgrades.

The other cornerstone of the push is SB 32, which continues cap-and-trade emissions requirements for large industrial polluters like oil refineries and power companies, implemented in California’s groundbreaking 2006 climate change law.

SB 32 increases those pollution reduction goals – specifically from man-made greenhouse gases, requiring the state to reduce emissions to 40% below its 1990 levels by 2030, and then increasing that to 80% below 1990 levels by 2050.

The bills, say Kevin de Leon, the leader of the state senate, are necessary not just for the environment, but to protect the state’s population and economy for future generations.

“This is a fight worth having because it’s a fight for our children’s health, it’s a fight for the economic future of the greatest state in the country,” he said at a recent press conference, also highlighting California’s longstanding role as a leader in policy making. “It is not hyperbole and it is not over dramatization to say the world is watching very closely.”

But speaking for oil companies, Beth Miller, spokeswoman for the California Drivers Alliance (CDA), an advocacy group formed by the Western States Petroleum Association – a trade organization representing petroleum companies including Shell, Chevron and ExxonMobile, chastised: “The bill contains no details on how this state will achieve those kinds of mandates.”

She warns that regulatory agencies could have the “authority to do things like restrict driving, when you can drive, on what days you can drive … put in penalties for people who drive minivans or SUVs.” Without details laid out in the legislation, “all of these are within the realm of possibility”, she says.

To push this dire message, CDA launched a massive media campaign with television and radio ads as well as direct mail pieces in recent weeks aimed at convincing average citizens the impacts of SB 350 will make their lives harder. It’s a tactic that supporters of the climate change measures call fear mongering, but which has resonated with many, especially those in the business community who worry about rising fuel prices.

On the legislative front, the Western States Petroleum Association and allies are targeting moderate Democrats in the state assembly, lobbying them to question if the measures provide proper oversight, would negatively impact business in California, and unfairly target a single industry.

“We would prefer that petroleum be taken completely out of SB 350,” said Miller.

De Leon and other supporters of the bills are hitting back hard with their own barrage of media events and one-on-one meetings with their legislative colleagues. This week alone, De Leon has unveiled statements of support from former legislative leaders, a long list of business supporters including a Silicon Valley trade group that includes companies like Google and Apple, a well-known climate change scientist and US senators Dianne Feinstein and Barbara Boxer.

State senator Fran Pavley, a close ally of De Leon, promised that the efforts to pass SB 32 and SB 350 were far from over. Democratic leaders are planning on increasing the push to keep their moderate fellows on track in the days leading up to a full vote of the assembly, which could come as soon as next Tuesday. And they are continuing to roll out more hits in the slew of media events to counter the oil industry narrative.

Their message is simple: don’t believe the hype.

“No one is going to outlaw SUVs, no is going to outlaw minivans,” says de Leon. “There is going to be no rationing of gas a la Mad Max … Those doomsday scenarios are not going to exist.”

But the clock is counting down – the last day of the legislative session is September 11. And as of now, the votes to pass the measures in the Assembly likely are not secured.

And there’s more at stake than the climate. California 77-year-old governor Jerry Brown, who is the state’s longest-serving leader (he was also governor from 1975 to 1983 and was elected again in 2011) has made climate change a major component of his legacy. De Leon is finishing up his freshman year as Senate pro Tempore, and a win on this contentious issue would affirm his ability to be a party leader.

Both plan to head to the United Nations Conference on Climate Change in Paris this December, where 190 nations will gather to discuss a potential global agreement – and where a defeat on California’s legislation would be a political black eye for the state and its leaders.

“Keep your eye on these next couple of weeks,” said another de Leon ally, Senator Mark Leno, at this week’s press conference. “It may be a bumpy ride.”