Flights to and from U.S. airports generate just 2% of the nation's carbon emissions. But worldwide, commercial aircraft are a major contributor to greenhouse gas emissions, producing more than 700 million tons of carbon dioxide per year. If aviation were a country, it would rank seventh in world emissions, just behind Germany and ahead of South Korea. And U.S. aircraft account for nearly one-third of the world's aviation emissions.
So some climate advocates were cheered this week when the Environmental Protection Agency (EPA) announced it had determined that greenhouse gases from aircraft endanger human health—a legal first step toward regulating U.S. aviation emissions. But many are also worried that, instead of opting to set its own aggressive standard for aircraft, the agency will instead work through what could be a cumbersome and sluggish international process.
That process “is shaping up to be extremely unambitious,” says Sarah Burt, an attorney with the environmental group Earthjustice in Washington, D.C. It could produce “a standard which has no effect on emissions reductions at all,” she worries.
How to address aviation emissions has become a growing issue. “Emissions have quadrupled since 1960, and the projection is they will triple again by 2050,” says Dan Rutherford, program director for aviation and marine transportation for the International Council on Clean Transportation (ICCT) in San Francisco, California. “It's a large emissions source that is essentially unregulated and growing quickly.”
In the late 1990s, international negotiators considered airline emissions such a hot-button issue that they left aviation out of the 1997 Kyoto Protocol’s targets for reduction of each nation’s greenhouse gases. They gave the job of developing a plan to the United Nations' International Civil Aviation Organization (ICAO).
ICAO has struggled for years with this task, causing frustration among some national governments and advocates. At one point, the European Union sought to impose its own regulations on aviation emissions but agreed to put those on hold in 2012 under pressure from the airline industry and other nations—including the United States. Among the arguments against unilateral E.U. action: that country-by-country regulations won't work in a business that crosses borders millions of times daily.
“As aviation is a global industry, with airlines and aircraft operators operating internationally and aircraft manufacturers selling their aircraft in international markets, it is critical that aircraft emissions standards continue to be agreed to at the international level,” wrote Melanie Hinton, a spokesperson for the U.S. industry group Airlines for America, in an e-mail to ScienceInsider.
But some environmentalists have pushed for the United States to set its own emissions curbs for airlines. Earthjustice and others sued EPA and won a favorable federal court ruling in 2011 that paved the way for the agency's 10 June “endangerment finding.”
Now they are concerned because EPA has made clear it plans not to forge ahead with its own standard, but to work through the sluggish ICAO process. There is a deadline, of sorts: ICAO has committed to announce new aviation fuel economy standards next February. EPA now says it will seek to influence those standards, with an eye to adopting them in the United States. (That would be the logical next step, if the EPA administrator finalizes the endangerment finding next year after reviewing public comment.)
“Our number one goal is to secure a meaningful international standard,” said Christopher Grundler, director of EPA’s Office of Transportation and Air Quality, during a 10 June telephone briefing for press. “There are sound environmental reasons to do so. An international standard would cover way more aircraft than simply a domestic standard, and would secure far more greenhouse gas emissions reductions.”
EPA has adopted ICAO standards on pollution in the past; in 1997, for example, that's how the U.S. agency finally addressed aviation emissions of nitrogen oxides, after years of controversy over the role these ozone precursors were playing in creating urban smog. But ICAO's standards typically have endorsed the technology already in use by most aircraft enginemakers—not pushed for the adoption of new technologies.
That has frustrated environmentalists, while easing concerns of affected industries. And industry analysts say any new EPA rule could follow the same pattern. “We believe an eventual EPA rule could fall short of environmentalists’ request for limits that are more stringent than ICAO’s,” wrote Washington, D.C., energy industry analyst Kevin Book in a note to his clients prior to EPA's endangerment finding.
EPA insists that its goal is to push for ICAO to do more than it has done in the past. A “meaningful” ICAO standard, the agency’s Grundler said, should do more than simply endorse what airlines are already doing. “It should provide for emissions reductions that would not take place in the absence of a standard,” he said. “In other words, the standard should drive innovations and emissions reductions beyond business as usual.”
Airlines have typically fought regulation that would force the adoption of such new technologies, saying that the cost of fuel is one of their largest operating costs and already provides an incentive for them to increase efficiency. “There's an industry line that the market [promotes emissions reductions] anyway,” said Tim Johnson, director of the Aviation Environment Federation in London, a nonprofit organization. Indeed, aircraft efficiency has increased some 70% since the 1960s.
ICAO's own 2010 review of the state of the science concluded that airlines could achieve a 40% improvement in fuel efficiency by 2020 over their 2000 mileage and could boost that to 80% by 2030. ICAO said such savings could be achieved with fairly conventional technology: advanced materials to reduce weight; low-friction paint coatings; and riblets, or small surface protrusions aligned with air flow to reduce drag. But recent research suggests the industry isn’t on track to realize such efficiency; one upcoming study by Rutherford's ICCT concludes that newly delivered aircraft will show just an 11% improvement from 2000 in efficiency. One reason for the slow pace, Rutherford says, has been dropping fuel prices, which have reduced the incentives for innovation.
In addition to simply improving fuel efficiency, ICAO envisions that airlines could also buy carbon offsets, and is planning to unveil a proposed carbon market for the industry in late 2016. That's why those who have been watching developments on aviation emissions believe next year will be an important one, with the United States now making clear it will play a key role.
“I think [the EPA action] does help for the fairly obvious reason that if ICAO comes up with a standard that is ‘business as usual,’ it runs the risk that it will not be considered an effective response to the endangerment finding,” Johnson said. “This adds pressure for a successful outcome.”
Earthjustice’s Burt is skeptical, because she expects the new rule to apply only to new aircraft designs, which do not occur often. And “the timeline is kind of outrageous,” she says, noting her group and others first petitioned EPA to act in 2007. “To say that it's going to take another year to essentially cut and paste ICAO standards is classic kicking the can down the road.”