In the latest attempt to force the U.S. government to do more to tackle global warming, California and a group of other states and environmental groups are expected to ask the U.S. Environmental Protection Agency to crack down on airline emissions, according to newspaper reports Wednesday.

California Attorney General Jerry Brown is expected to file a petition with the EPA asking the agency to impose limits on aircraft emissions of carbon dioxide, the most prevalent greenhouse gas. "Global warming is such a big challenge that wherever we can reduce greenhouse gases, we must do so. The EPA has abdicated its responsibility in this area for years, and it won't do its job until it's legally required to do so," Brown told the San Francisco Chronicle in a report published Wednesday.

Among those said to be joining California's effort are the states of Connecticut, New Jersey, New Mexico and Pennsylvania, plus New York City and the District of Columbia, Earthjustice, Friends of the Earth, Oceana and the Center for Biological Diversity. U.S. airlines' largest trade group, the Air Transport Association, on Wednesday disputed the need for the government to limit greenhouse gas emissions for airlines.

"The commercial airlines already are driven to be as fuel efficient and environmentally conscious as possible," said David Castleveter, spokesman for the ATA. Fuel costs account for about 28% of an airline's operating costs. U.S. airlines have improved their fuel efficiency 103% since 1978, Castleveter says, and ATA member airlines have committed to another 30% fuel efficiency improvement by 2025.

But the petitioners want the government to act, especially as air traffic grows. The Federal Aviation Administration predicts air traffic will rise 60% by 2025. The Chronicle, citing EPA figures, says aircraft account for up to 12% of greenhouse gas emissions produced by the U.S transportation sector.

Europe has already taken steps to regulate carbon dioxide emissions from aircraft. Last month, the European Parliament backed plans to cap greenhouse gas emissions on airlines flying within or into the 27-nation European Union. The airlines will be subject to the rules in 2011. The program, which involves buying and selling of pollution allowances, has been criticized by U.S. airlines.

The three environmental groups participating in today's filing say the EPA could lower aircraft pollution by forcing airlines to change the way they operate and encourage investment in new technology, according to the Chronicle. The petition says airlines can reduce fuel consumption by cutting the time planes are permitted to idle on runways and requiring the use of only one engine when they taxi to gates.

(Por Barbara De Lollis, USA TODAY, 06/12/2007)