Oregon's new budget bill would prevent Gov. Ted Kulongoski from implementing California's automobile emissions limits in Oregon. The governor has threatened to veto the restriction. He should reconsider. California's requirements will be costly to Oregonians while conferring few environmental benefits.

California is the only state allowed to adopt its own auto emissions standards and has used that authority to go beyond federal requirements. Other states can choose either California or federal emissions limits. Kulongoski and his environmentalist allies claim that adopting California's standards will make a big dent in regional air pollution and global warming, but they are mistaken.

Oregon already meets all federal air pollution health standards by a handy margin, including tough new standards for ozone and soot implemented last year. Some automobile emissions, such as benzene, can cause cancer at high enough exposures. But even in Multnomah County, with the highest auto pollution levels in Oregon, the lifetime risk of cancer from car emissions is less than one in 100,000.

Oregon's air is already clean and will only get cleaner. The feds tightened auto smog standards in 1994, 2001 and 2004. Most of the benefits of these standards--the 2004 standards require a 90 percent reduction below the emissions of current average car on the road--won't be fully realized until more than a decade from now as older cars are retired. The California standards add only a few additional percentage points of reduction. There's no reason to make Oregonians spend tens of millions of dollars each year [on their vehicle purchases] for tiny improvements in air that is already clean.

Carbon dioxide, blamed for human-caused climate change, is different from air pollution not only in that it is harmless to breathe but also because it is an unavoidable waste product of burning fossil fuels such as gasoline. Air pollution can be reduced with catalytic converters and computer-controlled engines. But reducing CO2 requires less driving or greater fuel efficiency.

Unfortunately, California's fuel efficiency requirements are all pain and no gain. Consumers will pay $1,000 to $3,000 more for cars that meet California's 30 percent CO2 reduction requirement. But even adopting this requirement nationwide would do almost nothing to slow climate change, reducing global temperatures by at most a few hundredths of a degree by 2100. Making a substantive dent in climate change would require much more draconian restrictions on driving and energy use.

Some might find the costs of California's standards a worthwhile tradeoff because consumers will recoup much of the extra cost in gasoline savings. However, consumers can already choose among dozens of car models that get more than 30 miles per gallon, yet the average motorist chooses a 21 mpg automobile. Larger, lower-mileage cars have amenities such as greater comfort, space and safety. Consumers who put a premium on mileage have many choices without the government forcing others into cars they wouldn't choose voluntarily.

California has already chosen costly environmental symbolism instead of people's real health and welfare. I hope Kulongoski won't force his state to follow California off that cliff.

Joel Schwartz is a visiting fellow at AEI.