As levels of traditional air pollutants like smog and soot continue to decline, regulators are setting their sights on the regulation of gases claimed to cause climate change - like carbon dioxide, usually referred to as CO2.
Now, California's regulators have passed rules that aim to reduce the carbon-dioxide emissions of the Golden State's vehicle fleet. But every indication suggests the California Air Resources Board's new rule, like its electric-car mandate of the 1990s, offers great economic pain for no environmental gain.
The board's latest decree sets a much lower standard for the amount of carbon dioxide that can be emitted by each year's new-car fleet sold in the state beginning in 2009. Ultimately, the required reduction in vehicle carbon-dioxide emissions for the fleet of vehicles sold in California will reach a stiff 30 per cent below current levels by 2016.
Unfortunately, the benefits of this low carbon-dioxide diet don't amount to much. The required 30-per-cent reduction in carbon dioxide certainly won't put a dent in global warming. Even taking every car in California off the road would reduce current global emissions of carbon dioxide by less than one-fourth of one per cent, a reduction that would have virtually no effect on the climate.
In fact, at current emission levels, reducing all motor fuel emissions in all of North America by 30 per cent would reduce global carbon emissions by only 1.5 per cent.
With emissions in developing countries like China and India far outpacing those in developed countries, the environmental effect of the new rules is likely to be undetectable in the long run. And that's assuming that automakers can come up with a fleet of cars that achieves those reductions - a dubious assumption at best.
A study by Sierra Research, an air-pollution consulting firm, found that contrary to the California regulators' claim, "vehicle design changes would need to occur at a rate that substantially exceeds historical practice, unless compliance is achieved by shifting motorists into small, lower-performance vehicles."
The costs of the new proposal border on the prohibitive. When the regulators proposed the new rule, they argued that motorists would save big at the gasoline pump - an estimated $1,703 over the life of each new passenger car sold in 2016.
The Sierra Research study, however, showed the regulators erred by lopping 30 per cent off the true cost estimates for developing key technologies needed to put their proposed carbon-dioxide reductions into effect. It also found the California officials were overly optimistic in assuming that such technologies as five-speed and six-speed automatic transmissions would be universally adopted by carmakers.
When taking out all of the regulators' unsupportable assumptions, Sierra Research found that new car buyers in 2016 would lose $3,357 over the lifetime of the vehicle compared with a no-regulation alternative.
A second cost likely would be dirtier air since forcing higher costs onto new cars causes people to hold on to their older, more-polluting cars much longer.
The perverse impact of the new regulation actually will be to slow the positive progress that California has made in reducing levels of traditional air pollutants.
While the new rules apply only to California, they're likely to increase new-car prices for buyers throughout the United States and Canada since 20 per cent of new cars are sold to Californians.
With that big a market at stake, automakers will have little choice but to apply the requirement to virtually every car sold in North America rather than go to the trouble and expense of fragmenting their production for two separate markets - California as one and the rest of North America as the other.
Unless one is gullible enough to believe that changing human actions through government coercion will save the Earth from the global warming disasters envisioned in the movie The Day After Tomorrow, California's new carbon-dioxide regulations are ill-advised. Their costs are too high and their benefits nearly non-existent.
Dr. Kenneth Green is senior fellow at Reason Foundation and Chief Scientist at Frasier Institute.