fter a long and bitter debate, lawmakers in California today passed the nation's strongest legislation to regulate emissions of the main pollutant that can cause warming of the planet's climate, a step that would require automakers to sell cars that give off the least possible amount of heat-trapping gases.
By the narrowest of margins, the State Assembly passed the California Climate Bill, which for the first time gives the agency that regulates air pollution in the state the power to limit emissions of carbon dioxide, the main gas that scientists say is building up in the atmosphere and causing a warming of Earth's climate.
The vote was 41 to 30, with 9 members not voting and with a majority of 41 needed to pass the bill. Democrats control the Assembly 50 to 30, and the vote was mostly along party lines, with Republicans in opposition.
With the California Senate having passed the measure, 23 to 16, on Saturday, the Assembly's action seemed to signal that the bill would soon go to Gov. Gray Davis for his signature, though a few procedural hurdles might still derail it.
Steven Maviglio, a spokesman for Mr. Davis, said the governor made this statement about the bill: "This bill represents good public policy, but it has been subject to many amendments over the past several days. I will read all the amendments when the bill arrives on my desk before making a final decision."
Environmental advocates called the bill the most significant step ever taken to control heat-trapping gases in the United States, which is the world's leading source of such pollutants but which, under President Bush, has refused to join a global pact to restrict their emissions.
Automakers contend that California is taking a unilateral step to increase the fuel efficiency of vehicles, something the federal government has not done for years. Because carbon dioxide is given off whenever gasoline is burned, the only way to cut how much of it vehicles produce is to make ones that burn less gasoline or to sell ones driven by electricity or by other means.
The measure would not take effect until 2005, and the first models that would come under its restrictions would be sold in 2009. Even so, environmental groups said this was the most important step to cut emissions of heat-trapping gases since global climate change first came to public attention some 20 years ago.
Fred Krupp, the president of Environmental Defense, a group that lobbied hard for the bill, said it was a sign that "solutions are at hand" for the threat of global warming.
"Finally," Mr. Krupp said, "somewhere in our governmental system, one state has taken action."
But other states, including Massachusetts, have taken steps, though more modest, to reduce emissions of heat-trapping gases.
Assemblyman Dario J. Frommer, a Los Angeles Democrat who supported the bill, said today: "In the long term, we'll all be served by cleaner air and reducing global warning. We have four of the dirtiest cities in the nation in this state. It is time for us to lead the nation in a responsible and measured approach, which is what we have in this bill."
But Assemblyman Dennis Hollingsworth, Republican of Murrieta, who opposed the bill, said: "This will cost lives. `The reason it will cost lives is that it will price people out of the market. So they will keep their older cars, which do not have the safety features of newer cars."
Automakers sought to thwart the bill with a vigorous campaign of television commercials and other publicity suggesting that the measure would result in a ban on sport utility vehicles and large cars.
In a compromise, the Assembly required that the bill not impose taxes or other prohibitions on large cars, and provided that automakers could pay other companies that emit heat-trapping gases to reduce their pollution, offsetting cuts that automakers would otherwise have to make.
Even so, the automakers reacted negatively to the measure passed today.
"This is another form of regulating fuel economy," said Chris Preuss, a spokesman for the General Motors Company. "That is strictly the right and authority of the federal government. There are more proactive ways of dealing with the environmental issues in California than this type of legislative approach."
Environmentalists argued that while fuel economy standards were regulated only by federal laws, California had the right to regulate all forms of air pollution, and that the current bill was carefully written to limit emissions of carbon dioxide, not fuel efficiency.
California is the largest market for automobiles in the United States, as well as the state with more serious air pollution problems than any other. Under federal clean air legislation, the state's air quality regulators are allowed to set standards for automobile pollution that are stricter than those imposed by federal law. In the past, many other states have followed California's lead in setting pollution rules on vehicles, and ultimately American automakers have been forced to build cars that meet California's standards and to sell them nationwide.
Heat-trapping gases, which are given off mainly when people burn fossil fuels, come from many sources; cars, homes, factories, power plants and farms are the most important. But transportation is the leading source.
This is the same august body that voted into existence a fleet of electric automobiles, which were to have been available for sale last year in California. That one sort of expired quietly, since Magic Batteries were not in fact invented, and in any case the state forgot that people would need electricity to run the damned things, had they in fact been produced.