'Greenhouse' ruling: An exhaustive look

A federal court decision upholding California's pioneering "greenhouse gas" law last week illuminated the state's unique right to set its own vehicle emission standards. Here's a primer on the controversy and what's at stake for consumers.

Q: What did the court decide?

A: The U.S. District Court in Fresno ruled in favor of California in a lawsuit brought by major auto manufacturers seeking to strike down the 2002 law before it takes effect next year. Judge Anthony Ishii disagreed with the auto industry's claim that the curb on climate-altering tailpipe gases amounts to an unconstitutional intrusion on federal regulation of fuel mileage.

Q: What do these pollution limits have to do with gas mileage?

A: The only practical way automakers can reduce emissions of carbon dioxide and other greenhouse gases – so named because of their heat-trapping effect in the atmosphere – is to make cars run more efficiently and burn less fuel.

Q: How much reduction in greenhouse gases would be achieved?

A: The restrictions, which apply only to non-commercial vehicles, are expected to result in 22 percent fewer emissions of carbon dioxide by 2012 and a 30 percent reduction by 2016, compared with 2002 model cars, according to the state Air Resources Board, which regulates the law. That translates into 155, 200 fewer tons of carbon dioxide by 2030, air board estimates show.

Q: Would these regulations make any measurable difference in global warming?

A: By themselves, no. While California is the world's 10th-largest emitter of greenhouse gases, it's responsible for barely 2 percent of the carbon dioxide produced worldwide, according to the state Energy Commission. The state's contribution to global warming simply is too small for the emissions cuts – or any amount of state regulation – to make a difference, scientists say. The law's supporters are nonetheless optimistic, banking on the state's legacy as a national and even international trailblazer of pollution controls. As California goes, so goes the rest of the world, they say.

Q: How would the new regulations affect the type and cost of cars offered for sale?

A: Air board officials say automakers can achieve the bulk of required emission reductions using technology available today, without sacrificing the design or size of the vehicle. Some of the fuel- saving features are in models already on the road, such as more efficient valve-timing, sleeker aerodynamics and smoother-rolling tires. The added production cost would be about $1,800 per vehicle, they say. Automakers say the law would inflate production costs as much as $6,000 a vehicle.

Q: Why did the automakers sue California?

A: California is the only state permitted under the federal Clean Air Act to set its own rules on auto emissions and fuels. Other states, however, can adopt the California standards. Many states, particularly in the populous Northeast, typically have followed California's lead. The ripple effect leaves automakers with no economical choice but to build cars for the whole nation that meet the stricter – and often costlier – California rules.

Q: Why is only California allowed to enforce tougher emissions standards than the federal government's?

A: In passing the original Clean Air Act, Congress in 1970 made an exception for California because its air pollution was already so severe and because its smog-fighting efforts predated the federal law. Congress said California should have the "broadest possible discretion in selecting the best means to protect the health of its citizens."

Q: With the legal victory now in hand, when will California begin enforcing the greenhouse gas law?

A: California still needs the Bush administration's permission to enforce the law. To get the waiver, the state must convince the U.S. Environmental Protection Agency that it faces "compelling and extraordinary conditions."

Q: Where does California's request for the waiver stand?

A: Attorney General Jerry Brown has sued the EPA to force a decision on the state's 2-year-old request for the waiver, and EPA Administrator Stephen Johnson has promised to decide in the next two weeks. If and when the waiver is approved, California and 13 other states that adopted the same law can enforce it – but more lawsuits could delay that.

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