Forget everything you've heard about airlines and CO2 emissions. The news is much worse than anyone thought.

A recently disclosed report finds that airlines are spewing 20 percent more carbon dioxide into the environment than previously estimated and the amount could hit 1.5 billion tons a year by 2025. That's far more than even the worst-case predictions laid out by the International Panel on Climate Change.

If you're looking to put that number in perspective, the European Union currently emits 3.1 billion tons of CO2 annually. Yup, that's the entire 27-nation, 457 million person EU.

The report, "Trends in Global Aviation Noise and Emissions from Commercial Aviation for 2000 to 2025," is among the most authoritative estimates of the industry's growth in emissions. It was produced by the U.S. Department of Transportation, Eurocontrol, the Manchester Metropolitan University and the technology company QinetiQ. They used a variety of models to calculate current fuel use, then projected out to 2025 based on these findings and anticipated increases in air travel.

"Growth of CO2 emissions on this scale will comfortably outstrip any gains made by improved technology and ensure aviation is an even larger contributor to global warming by 2025 than previously thought,"

Jeff Gazzard, a spokesman for the Aviation Environment Federation, the group that uncovered the report, told the Independent. "Governments must take action to put a cap on air transport's unrestrained growth."

The report was written for an aviation conference in Barcelona last year, but was turned down by organizers. It remained out of sight until the Aviation Environment Federation unearthed it and announced somewhat dramatically that the report had been "suppressed." Suppressed or not, it has provided fresh ammunition for environmental groups trying to pressure governments into restraining commercial aviation growth.

The response of the airline industry, which is exempt from the Kyoto Protocol for reducing greenhouse gases, isn't surprising. The International Air Transport Association, a trade group representing 240 airlines, says it is working as hard as possible to produce binding emission-reduction targets and argues skyrocketing fuel prices are pushing airlines to find alternatives to fossil fuels.

"With fuel costs doubling in the last year, airlines already have an incentive to work towards greater efficiency," a spokesman said. "There has been a 70 percent improvement in fuel efficiency in the last four decades. Aviation is a benchmark of environmental

responsibility for others to follow."

In case you were looking for more good news, the study also found that the number of people forced to deal with serious aircraft noise will rise from 24 million in 2000 to 30.3 million by 2025 – this despite the introduction of quieter next-generation jets.

Photo courtesy Flickr user Steffe.