NEW YORK (CNN/Money) - Last week, California approved new regulations requiring automakers to cut cars' greenhouse gas emissions by 25 percent starting with the 2009 model year and up to 34 percent by 2016.

If you live in New York, Massachusetts, Vermont or Maine, the cars you buy may have to abide by those rules, too, because those states currently follow California's rules on automobile air pollution. New Jersey, Connecticut and Rhode Island are in the process of adopting them, as well.

It's still unclear, though, whether all of those states will also require vehicles to abide by the California rules in 2009. A spokesperson for the New Jersey state agency for air quality, for example, said the issue was still being discussed as did a representative for New York's.

Altogether, that means that about 22 percent of America's population could be living with these rules. Depending on whom you believe, that will either make the planet safer from the threat of global warming or force you to pay thousands more for a car with no appreciable benefit.

Under federal environmental rules, states are not allowed to set their own emissions requirements for cars. There is one state that is exempt from that rule, however: California.

The other 49 states can choose either to enforce the federal government's emmission standards or California's more stringent rules. Thus, California's Air Resources Board, which approves new emissions standards, carries considerable weight beyond the state's borders.

"If it was just California, the auto industry would just say 'Oh, its just those crazy Californians," said Jerry Martin, a spokesman for CARB.

California has traditionally been an environmental tough guy, too, passing stiff regulations to help clean up some of the dirtiest air in the nation.

Automakers object to California's rules on three fronts. First, they argue, the rules aren't based on sound engineering principles. Second, if cars were to meet these rules, they would cost thousands of dollars more. Third, global warming is none of CARB's business, anyway.

Here's a breakdown of the argument between CARB and automakers, represented by the Association of Automobile Manufactures.

CARB: The auto industry should be able to meet these requirements by simply using and combining current fuel-saving technologies on more vehicles at a cost of about $1,000 per vehicles

AAM: It's not that simple. Complying with these rules would add about $3,000 to the sticker price of every car sold in these states.

"We are not asking the car companies to invent one thing," said CARB spokesperson Martin.

For example, using a small engine with a turbocharger can save seven percent in fuel with no loss of maximum horsepower. A six-speed transmission, rather than a four-speed, can save four percent. Variable valve timing and lift can save from three to eight percent, he said.

"That's like saying if I go on three diets at once, I'll lose three times as much weight," said Gloria Bergquist, a spokeswoman for the Alliance of Automobile Manufacturers, an organization that represents Ford, DaimlerChrysler, General Motors and several other auto manufacturers..

AAM: This is nothing more than an illegal attempt to regulate fuel mileage. Only the federal government is allowed to do that.

CARB: Did we say anything about fuel mileage? I don't think so.

There is only one way to reduce greenhouse gas emissions from vehicles and that's to improve fuel efficiency. So, in effect, these rules will force manufacturers to improve fuel efficiency.

But as AAM points out, CARB isn't allowed to set fuel efficiency standards. But as CARB points out, the regulations say nothing about fuel economy. Just emissions.

AAM: What is CARB doing worrying about global warming, anyway? CARB is supposed to control smog and the emissions in question may be bad, but they aren't smog.

CARB: The California legislature mandated that CARB tackle global warming-related emissions. Besides, increased heat and radiation from the sun indirectly contributes to smog in a variety of ways.

The AAM also points out that reining in greenhouse gases in California would have no real effect on global warming, reducing the earth's burden of greenhouse gases by a fraction of a percent.

CARB agrees that just regulating greenhouse gas emissions from cars in California would do practically nothing about global warming. But that doesn't take into account the contribution of additional states taking on the standard, which could raise the total impact to as much as a couple of percentage points.