The European Commission will unveil a compromise proposal on limiting emissions from new passenger cars, in a battle that has pitted Europe’s ambitious environmental goals against some of the world’s biggest carmakers.


After fierce lobbying by European automakers, the 27-member commission, the executive body of the European Union, is expected to endorse a watered-down blueprint that would impose a limit on carbon dioxide emissions from new cars averaging 130 grams a kilometer by 2012. The initial proposal, which was shelved last week, set a target of 120 grams.


Environmentalists accused the European Union of surrendering to the auto industry, saying the plan would do little to dissuade carmakers from continuing to produce gas guzzlers. But the auto lobby, concerned that the measure posed a risk to profit and could spur factory closings across the Continent, is preparing for a further fight on the initiative, which forms the basis for coming legislation that must be approved by European member countries.


Under the proposal, the commission will accept the industry’s demand for an approach that reduces pressure on manufacturers to alter their car designs. Instead, the carmakers will be encouraged to find other ways to reduce emissions, like using more biofuels, improving tires and gear boxes, and educating motorists about fuel-efficient driving.


Sigrid de Vries, the spokeswoman for the European Automobile Manufacturers Association, which represents 13 manufacturers including BMW, Volkswagen and Ford, said the compromise still placed an expensive burden on the automotive industry. “The risk is that it will lead to a loss of jobs and production in Europe while making cars more expensive for consumers,” she said.


The European auto industry employs six million people, the bulk of them in big European Union countries like Germany, France, Italy and Spain.


Fiat’s chairman, Sergio Marchionne, warned the commission’s president, José Manuel Barroso, that the previously proposed 120-gram emissions limit would shift thousands of jobs overseas. He argued that the commission’s own consultants had calculated that this limit would add about $4,700 to the average retail price of a new car.


Some auto executives say they also fear that a limit on carbon dioxide emissions will unfairly favor companies like Renault and Fiat, which produce smaller cars. “This is a business war in Europe,” Porsche’s chief executive, Wendelin Wiedeking, told a recent shareholders meeting in Stuttgart. “It’s the French and Italians up against the Germans.”


Environmental groups sought to rein in the automakers’ campaign, arguing that cars accounted for more than a tenth of European Union countries’ carbon dioxide emissions. They said many European car companies were intent on producing big cars, even though Japanese, French and Italian automakers had shown that producing more fuel-efficient ones was viable. The Toyota Prius hybrid, for example, emits 104 grams of carbon dioxide a kilometer, and the Citroën C1, 109 grams.


Dudley Curtis, spokesman for Transport and Environment, an environmental group, said: “This proposal is a pathetic caving in to industry. The carmakers are choosing to market big gas guzzlers. The European Commission’s target has been watered down several times, and in light of the climate change threat, this is very, very disappointing.”


The European Commission’s environmental spokeswoman, Barbara Helfferich, said she was confident that European Union countries would still be able to reach their Kyoto Protocol target, which aims to reduce greenhouse gas emissions 8 percent below 1990 levels by 2012.


European Union officials who have seen the proposal said the environmental commissioner, Stavros Dimas, had wanted to introduce far more ambitious carbon dioxide limits for cars. But those officials, who asked not to be identified by name because they were not authorized to speak publicly, said Mr. Dimas had been blocked by a group of commissioners led by the industry commissioner, Günter Verheugen, who wanted the burden to be shared by carmakers and equipment makers.


Even Chancellor Angela Merkel of Germany, currently the European Union president under a rotating arrangement, waded into the debate, threatening last week to block the commission proposal and calling for different limits to be set for different types of cars.


The European Union recently introduced a strategy to fight global warming by reducing its reliance on imported oil and natural gas and promoting the use of renewable energy sources.


In an effort to advance the climate-friendly agenda, European officials said Mr. Dimas indicated that he was considering trading his large luxury Mercedes for a more fuel-efficient Lexus. Such a move would breach convention in Brussels, where commissioners typically use European cars, usually BMWs or Audis.