Too much air time

My girlfriend and I like to think we are environmentally conscious. We try to eat mostly plants, buy local, take public transportation and so on. But we have a carbon blind spot. She lives in London, I live in New York, and the trans-Atlantic flights we take to see each other quickly eclipse our other efforts.

It turns out we aren’t the only ones. Research shows that people regard aviation differently from other activities that could harm the environment. Air travel has a deep-rooted hold on middle-class life, so it’s not surprising that two recent international agreements spared aviation from tough emissions reductions. In December, the Paris climate agreement exempted aviation from cuts, and in February, the International Civil Aviation Organization announced emissions standards that conservationists and legal experts consider too weak to have any effect.

Air travel accounts for roughly 5 percent of man-made carbon emissions and its climate impact keeps rising as more and more flights lift off. The world’s fleet of planes is expected to double in number over the next 20 years, according to Boeing. By 2050, researchers expect aviation to account for about 15 percent of global carbon dioxide emissions, and carbon dioxide is only half the problem.

Even as the automobile industry struggles to meet tougher fuel efficiency standards, the aviation industry benefits from weak emissions standards and low taxes. The federal tax on commercial jet fuel is about one-fifth the rate for standard vehicle gasoline and diesel. The industry benefits from other subsidies, too. Boeing, for example, receives among the most government loans and subsidies of any American company, making it “exceptionally favored by Uncle Sam,” according to watchdog group Good Jobs First. While some environmental groups push for tougher environmental rules, they have made little headway.

“There’s no logical reason why we keep air travel tax free or nearly tax free. But here we are in the 21st century subsidizing the most fuel-intensive form of transport,” says Andrew Murphy, who focuses on sustainable aviation at Transport & Environment, a Brussels-based advocacy group.

Academics who have studied the problem — and there are a surprising number who have — say we regard flying differently from driving, turning up the air conditioning and other activities that contribute to global warming. Their point isn’t that we think differently about the environmental impact of air travel, it’s that we rarely think about it at all.

So it shouldn’t be surprising that when aviation emissions are discussed in the media, the talk often centers around the hypocrisies of climate activist Leonardo DiCaprio using a private jet, technocrats taking Learjets to Davos or climate scientists flying from conference to conference (as academics, they are part of a “high carbon research culture“). This talk can present a false expectation of perfection on the part of individual consumers, when it turns out many of us have something in common with DiCaprio.

Most people, of their own volition, will not cut back on flying, no matter their attitude toward the environment, research suggests. A study by Graham Miller of the University of Surrey in England identifies a sense of entitlement with regard to holiday travel, an urge to keep up with the Joneses (what other researchers have termed “trophy tourism”) and an unwillingness to take fewer vacations. Even people willing to make eco-friendly adjustments at home are not willing to change air travel patterns, which are linked to aspirations of freedom and mobility, according to a study led by Stewart Barr, a geographer at the University of Exeter.

“The same person who says, ‘I’m quite green, I recycle, I drive a hybrid car,’ also says, ‘I want to go to Sri Lanka on vacation for the week,’” says Scott Cohen, a travel expert at the University of Surrey.

In a paper titled “Binge Flying,” Cohen describes air-travel vacations as potentially addictive behaviors that at times involve a ‘high’ and a release from inhibition, followed by a ‘low’ upon return home that can trigger the planning of another trip. Denial mechanisms are used to assuage guilt about environmental cost. But just showing up in a crowded airport helps relieve any guilt, as it reminds the flyer how normal his behavior is.

Not everyone agrees that flying is a true addiction, in the medical sense. Psychologist Mark Griffiths of Nottingham Trent University in England criticizes Cohen’s study, arguing that flying is not akin gambling or substance abuse.

Cohen agrees that flying should not be classed with those activities; he regards air-travel vacation as a broader socio-cultural addiction, a habit deeply embedded in Western society.

Or at least a well-to-do subset of that society: In fact, only a very select group reaches our skies. Just 3 to 4 percent of the global population flies at least once per year, according to Paul Peeters, a sustainable transport expert at NHTV Breda University in the Netherlands. “Clearly, there is a relationship between income and the amount that people fly,” he says. “In many countries, only the rich can.”

Even the world’s largest airplane manufacturer acknowledges the issue — but says cars are worse. Flying is “far more CO₂-efficient than driving,” argues Boeing spokesperson Jessica Kowal. She cites a report by Michael Sivak, a psychologist who studies transportation at University of Michigan. He concluded that driving uses about twice as much energy as flying, per passenger per mile.

But environmental impact isn’t just about how much fuel gets used, and it’s not just about carbon dioxide, either. It turns out that, pound for pound, flying is especially damaging. The data are not yet conclusive, but emissions at high altitudes appear to have greater impact because greenhouse gases like nitrous oxide, water vapor and soot are deposited directly where their effects are strongest — in the troposphere and stratosphere, the levels of the atmosphere closest to Earth. This magnifies the effect of the emissions by 1.5 to 4 times, Peeters estimates; the Intergovernmental Panel on Climate Change currently uses the figure 2.7. This means that carbon dioxide probably accounts for less than half of aviation’s climate impact. So while Sivak’s comparative study dealt with carbon dioxide emissions, it did not account for a flight’s total environmental damage.

Aviation’s impact on the climate has grown despite improved fuel efficiency and better pollution control equipment. The reason for this apparent paradox: We’re flying a lot more than we used to.

Just as new roads induce us to drive more, the increasing convenience of air travel  induces us to fly more. Research shows that we reserve a certain amount of time for commute or travel in our minds, whether we are in a village in Africa or a city like New York. When technology improves, we simply travel farther in the same allotted time period. So we end up flying extraordinary distances that we wouldn’t consider reasonable by other means.

When improved technology increases consumption of a resource in this manner, canceling out new efficiencies, economists call it “Jevons paradox.” The aviation industry has improved fuel efficiency by at least 120 percent in the last four decades, according to the leading airline trade group, but during that time the total amount of aviation fuel burned has nonetheless continued to climb.

Boeing and other manufacturers aim to achieve additional efficiencies in the coming years by building more aerodynamic planes, developing biofuels, and modernizing air traffic control patterns so that flights go the shortest possible distance. Turning a favorite phrase of environmentalists on its head, Kowal of Boeing writes, “‘Business as usual’ in the aviation industry is all about improving fuel efficiency.”

But progress will be slow because modern jets cost hundreds of millions of dollars each and are built to fly for decades. Today’s designs may still be in the air in 2080, after years of development and certification, and then decades of production and operation, said Peeters, a former aircraft engineer. “People are looking for a silver bullet like algae or hydrogen planes,” says Cohen, citing two ideas for alternate fuels. “They want an organic, zero-emissions flight, and the idea gets played up in the media, but the literature does not suggest that it’s on its way.”

For many years, the European Union tried to include trans-Atlantic flights in its cap-and-trade system for carbon emissions, but the Obama administration, in order to protect U.S. airlines, fought against the rule. Ultimately, the EU law was changed to include only flights within Europe.

Last year, the Environmental Protection Agency declared that carbon emissions from airplanes do pose a risk to public welfare and are therefore subject to regulation, but delayed further action until the International Civil Aviation Organization’s standards were announced; now that they have been, the big question is how the the administration will respond to those weak standards. Environmental groups are demanding strong action.

“We believe the EPA has a duty to substantially reduce airplane emissions, and if they don’t, they need to be brought to account for it,” says Patrick Sullivan, a spokesman for the Center for Biological Diversity. “We have taken legal action against the EPA before for dragging its feet on this very issue.”

But pressure for reform from environmental groups may have limited effect, since the type of people who set policy also enjoy the benefits of air travel. “Policymakers are dependent on air travel for their jobs and their personal lives, often to see their families,” says Cohen, the travel researcher. “There’s not a huge push for change because it would threaten lifestyles.”

A few people, at least, have changed their lifestyles. A pair of leading climate change scientists in England, Kevin Anderson and Alice Bows-Larkin, haven’t been on a plane since 2005. My girlfriend thinks I’d better fly over to interview them.