Flight shaming’s surprising power

When the trend of air travelers feeling guilty about their carbon footprints first arose, it seemed to some in the U.S. that it could be a passing fad. Now it looks like flight shaming is not going away and could even begin impacting aircraft designs. Adam Hadhazy checks in with environmentalists and the aviation industry.

For a country of barely 10 million people, Sweden has a history of punching above its weight, bestowing upon the world such household names as IKEA, Volvo and ABBA. Now one of the latest Swedish exports to go global is “flygskam” or “flight shaming,” a reference to the guilt that some airline passengers feel about the environmental impact of their flying, particularly over aviation’s carbon dioxide emissions that contribute to planetary warming.

Catchily branded eco-consciousness is nothing new, of course, and aviation has long been caught in green crosshairs. What is striking, however, is that flight shaming is having a discernible impact — and not, as one might expect, on the perennially easy target of the wealthy flying in business jets, but on average air travelers. Commercial airline passenger numbers have downticked in Sweden, for instance. Several European countries are eyeing legislation to promote train travel while making flight taxes more punitive for ordinary flyers.

In response, airline companies and aviation advocacy organizations have defended their record and made multiple gestures acknowledging they’ve heard passengers’ concerns.

The rise of flight shaming could prove a pivotal moment in the trajectory of the aviation industry. The movement might succeed in coalescing long-standing concerns of aviation’s environmental impact, possibly leading to significant business changes that then inevitably lead to technological changes.

Flight shaming is “suddenly a thing,” says Brian Foley, founder of the aerospace-focused consultancy Brian Foley Associates. “Companies and people are strategically positioning themselves for how to handle this, so [flight shaming is] definitely one of the more urgent issues for this decade.”

Easy target emissions

Aviation industry executives see undue finger-pointing given their sector’s relatively small slice of the greenhouse gas emissions pie — right around 2.5%. Richard Aboulafia, an analyst with the Virginia-based Teal Group points out that data centers worldwide are estimated to contribute an even bigger share, closer to 3%. Yet data centers and the online services they undergird do not receive anywhere near the level of criticism and scrutiny as aviation, Aboulafia says. A big reason is perception; goofing off on Facebook from the comfort of one’s own smartphone is not as obvious as hurtling along at 35,000 feet. “You don’t see the consequences of your actions,” says Aboulafia. “With air travel, you see it right away. You get on a metal tube and you’re flying through the air, burning hydrocarbons.”

Joe Wilding, chief technology officer at Boom Supersonic in Colorado, says the shaming is a “bit unfair” because it discounts the societal benefits of air travel. The company is designing supersonic airliners that will “remove the barriers to experiencing the planet,” as he put it in a presentation at AIAA’s SciTech Forum in January.

Yet where the climate-conscious — flight-shamers included — might have a point is with aviation’s relative intensity of emissions and the sector’s projected emissions growth. Pound-for-pound, over a short period of time, few human activities generate climate-altering gases with as much gusto as aviation. It’s not that jet fuel is especially carbon-heavy; burning a gallon of it produces 9.57 kilograms of CO2, comparable to gasoline at 8.89 kg per gallon. But the fact that thousands of gallons are burnt on a typical domestic flight, and tens of thousands on international flights, racks up emissions quickly. “It’s a really easy way to burn multiple barrels of oil in a given day in one fell swoop,” says Dan Rutherford, director of aviation programs for the International Council on Clean Transportation, a Washington, D.C.-based nonprofit research group. Rutherford has diligently tracked his own carbon footprint and calculated that on the days he flies, his footprint multiplies 75-fold.

Growth-wise, the current worldwide fleet of approximately 22,000 commercial aircraft is projected to double by 2037 in order to ferry around twice as many passengers as today, currently at 4 billion annually. Such growth would put aviation’s global emissions share closer to a whopping 10% come midcentury, according to the United Nations’ International Civil Aviation Organization. That’s not counting the possible return of commercial supersonic flight, tentatively slated for the mid-2020s by Boom, which plans scheduled passenger service, and Nevada-based Aerion, which plans to start with private jets. Estimates vary, but these planes could generate between two and a half to seven times the carbon emissions of subsonic aircraft, according to studies by the International Council on Clean Transportation and other research groups.

The aviation industry responds that it has made considerable gains in addressing emissions and is committed to further improvement. A modern transcontinental flight, for instance, emits on average about half of the carbon dioxide of a flight 30 years ago. The latest generations of aircraft continue to make gains. For instance, the Airbus A320neo family, which entered service in 2016, is 15% more fuel-efficient than its predecessor generation, courtesy of new Pratt & Whitney engines, airframe tweaks and the addition of drag-reducing blended winglets (nicknamed sharklets because of their uncanny resemblance to a shark’s dorsal fin).

“Credit is never given to the aviation industry for engine technology that is always improving, aerodynamics that are improving,” says Foley. “It goes unnoticed.”

Where flygskam has taken off, or stayed grounded

Some environmentally minded individuals and groups contend, though, that aviation could and should be doing far more.

In that vein, Swedish singer Staffan Lindberg publicly announced his intent to fly less, coining the term flygskam back in 2017. Another famous Swede, the opera singer Malena Ernman, signed on to Lindberg’s cause. The movement gained additional momentum because of Ernman’s daughter, now-17-year-old Greta Thunberg, who has emerged as a global climate activist and was named Time magazine’s Person of the Year 2019. (Flight shaming has also thus been dubbed the “Greta effect.”)

So far, the impact appears greatest in Sweden. Scandinavian Airlines has blamed flight shaming for its traffic falling 2% compared to the prior annual flight period, while Sweden’s state-owned airport operator has reported a significant drop — 9% — in the number of annual domestic flight passengers.

Like other European countries, Sweden has a well-developed rail system. It provides an attractive domestic alternative to flight in terms of cost, time and lower emissions. Not so, however, in the United States, a sprawling, rich country and the world’s largest aviation market. Outside of the small, densely populated northeast, rail is rarely competitive with air travel — a key reason why analysts say flight shaming has not registered in U.S. aviation data — or at least, not yet. “You have to have an alternative to air travel wherever [flight shaming] does get traction,” says Foley, “and really the only logical place after Sweden would be Europe.”

Evidencing Europe’s seriousness, some legislators in France have proposed a ban on most domestic flights. Germany, meanwhile, intends to institute minimum air travel costs, raise flight taxes and slash train taxes by more than 60%.

This sort of activity dovetails with a report from UBS, the Swiss bank, which does suggest that America and other big markets, such as China, could soon feel flight shaming’s impact. The bank surveyed flyers in countries including France, Germany, the United Kingdom and the United States, first in May 2019 and then again in October 2019. The results showed that the percentage of respondents who claimed they had foregone at least one flight because of environmental concerns doubled from 21% to 42% in just that short span. Celine Fornaro, head of European Industrials Equity Research at UBS, commented in the report that flight shaming is “gaining momentum,” further borne out when UBS surveyed flyers in the additional countries of Australia, China, Japan and Sweden.

Some steps taken

The International Air Transport Association, or IATA, is accordingly not assuming that flight shaming will turn out to be an environmental fad that fades away. The trade group, which represents 300 airlines worldwide, has announced a campaign in 2020 to push back against flight shaming and highlight the industry’s substantial efforts to reduce its carbon footprint.

A large share of those efforts harkens back to 2009, when airlines came together through IATA to pledge a set of environmental targets. These included a U.N.-adopted efficiency standard for new aircraft, an aviation carbon offsetting program known as CORSIA, short for Carbon Offsetting and Reduction Scheme for International Aviation, and initiatives to certify sustainable aviation fuels, or SAFs, such as biofuels with lower carbon footprints.

The targets, though, “were really all symbolic, not substantive,” says Rutherford. The efficiency standard was crafted such that new Airbus and Boeing aircraft already under development would meet it; CORSIA by its design does not address fundamentally reducing sector emissions; and SAFs — as of 2018 — have accounted for a measly two-one-thousandth of 1% of global jet fuel use, Rutherford says.

Now with the rise of flight shaming, Rutherford thinks the industry is in for a fresh reckoning. “Flygskam hit, and there’s a realization that ‘no, [those targets are] not going to be enough,’” says Rutherford. “I’m increasingly optimistic that we will see a fundamental shift toward decarbonization now.”

The future, sooner or later

Where and how might this shift occur? On the business front, Rutherford thinks airlines will increasingly pledge carbon neutrality, setting their own emissions targets and highlighting their carbon offsetting outlays. (JetBlue, for example, announced this intention in January.) In addition, more airlines will offer passengers the option of lessening their guilt by purchasing carbon offsets; Delta, Ryanair and British Airways are among the bigger carriers to have offered this option, and in some cases going back over a decade, though the number of carriers worldwide offering some degree of offsetting has ramped up. The offsets fund various carbon-reduction projects, such as planting trees and introducing fuel-efficient cooking stoves in developing countries.

Nevada-based Aerion, for instance, has pledged to plant 100 million trees to offset the emissions from its future fleet of AS2 supersonic business jets, scheduled to start service in 2026. Also, the GE Affinity engine that GE Aviation is building for AS2 is designed to work with sustainable aviation fuels. “The entire fleet will be carbon neutral,” said Matthew Mejia, Aerion’s chief financial officer, at the U.S. Chamber of Commerce’s Aviation Summit in Washington, D.C.

The efforts boil down to more than retaining customers; it’s also about satisfying investors. In an annual letter to executives, CEO of Blackrock investment firm Larry Fink wrote that “climate change has become a defining factor in companies’ long-term prospects.”

“He basically said, you guys don’t deal with this, we’re not going to be investing in your companies,” Bradley Tilden, CEO of Alaska Airlines, told attendees at the Aviation Summit. “This isn’t sort of a fringe issue for the far left anymore. People are saying this is a central issue for corporate America, that we actually need to be doing something about it.”

An October report from Citi, the multinational investment bank, outlined how significant such offset practices could be in the new era of flight shaming. For leisure travel alone, Citi put a cost figure of $3.8 billion for carbon offsets over the next five years (though with the caveat that this estimate could be 10 times too low). Airlines would absorb most of this expense, even when some cost is passed on to passengers, because higher flight prices might discourage travel.

On the technological side, meanwhile, achieving lower emissions boils down to fuel, engines and airframes. Fuel-wise, sustainable aviation fuels are chemically similar to standard, kerosene jet fuel. SAFs come from renewable feedstocks as varied as cooking oil to leftover forestry wood to algae. Overall, they have significantly lower life-cycle carbon footprints compared to fuels derived from buried hydrocarbons. At present, though, SAFs remain too expensive for wide availability and adoption.

Take Boom Supersonic. The company plans to power its XB-1 demonstrator plane with carbon-neutral synthetic fuel made by Prometheus Fuels of California. Prometheus sucks carbon dioxide from the air and converts it into fuel via a process called direct air capture. Availability of SAFs permitting, Boom might fuel its operational Overture aircraft with the new fuels. For long-haul air travel, “there’s really no good alternative to jet fuel today and nothing coming anytime soon,” says Boom’s Wilding.

IATA’s current goal is to increase SAFs’ use to 2% by 2025 — which doesn’t sound like much, until one realizes it’s about a 1,200% increase over today’s production.

Engines-wise, there remain some efficiencies to squeeze out of conventional internal combustion engines. “The airframers, Boeing and Airbus, they are very good at turning the screws on Rolls-Royce, GE and Pratt & Whitney to always get better engines,” says Rutherford. The aviation industry’s goal is to eventually transition to emissions-reducing hybrid propulsion, where fuel is burned primarily or exclusively on energy-intensive takeoffs, while cruise is purely electric. And after that, the technological goal is fully electric flight provided by a new generation of airframes smaller and lighter than today’s. “Engine manufacturing companies are looking toward the next chapter in aviation propulsion, and that chapter is electric,” says Foley. Yet even hybrid propulsion in any mainstream commercial capacity looks to be at least a decade away, Foley adds.

Also a ways off is any major revamp of airframes. Going back decades, airframers have focused on “reengining” existing airframes, versus taking the riskier, capital-intensive plunge for clean sheet design. Rutherford’s group published a study in 2016 that found that constant reengining is getting in the way of bold configuration changes that would deliver substantially better aerodynamics, while taking advantage of new, lightweight materials. “Where we’re seeing things stall is actually on the airframe side,” Rutherford says. “Our conclusion was that new aircraft fuel efficiency is only improving about half as fast as it could be because of the reengining issue.”

The design of the 737 MAX could be a case in point. “The 737 MAX debacle has really changed some thinking,” Rutherford says. With the MAX, Boeing tried a major reengining of its classic 737 design, delivering better fuel efficiency in the process. But compared to prior 737 generations, the MAX’s new engines with their large, efficient front fans had to be mounted farther forward under the aircraft’s wing, complicating the aerodynamics. The engines produced lift that tended to tilt the airplane’s nose up, potentially triggering a stall, so Boeing added the Maneuvering Characteristics Augmentation System, or MCAS, software to the cockpit to tip the nose down should sensors report a too-high angle of attack. That system was partly blamed for two fatal crashes, one in 2018 and one in 2019. The second crash prompted a worldwide grounding of the 737 MAX fleet at a cost of at least $18 billion to Boeing. “What could [Boeing] have done if they invested that $18 billion directly into a new airframe?” says Rutherford. “Probably something pretty radical.”

Just one example is the trussed wing design Boeing has long worked on. Trusses from the plane’s underside help support a top-mounted wing that is both longer than today’s wings, as well as shorter between the wing’s leading and trailing edges, and with less sweep. Another cutting-edge airframe rethink is the “double bubble,” pursued by NASA and the Massachusetts Institute of Technology. It fuses two aircraft body tubes to create a wide-body craft with three, ultra-high-bypass-ratio turbofan jet engines mounted in the rear. An even more revolutionary concept that gets away from tube-and-wing design is the blended wing body. Instantly recognizable as the distinctive shape of the Northrop Grumman B-2 “stealth bomber,” the whole aircraft generates lift while minimizing drag. All three designs deliver better fuel economy, and paired with still-better engines and fuels, would drastically lower emissions by several tens of percentage points.

Wilding of Boom thinks a solution will eventually come. “As a society, as a world, let’s keep doubling down on innovation in those fronts because I think it will get there. Or who knows, maybe there’ll be some other energy source, fusion perhaps, in the next couple of decades that comes out that could solve this problem. But none of that is imminent, so in the meantime we’ve got to do what we can do with what we can do.”

Change in the air?

It remains to be seen if flight shaming galvanizes the public, and in turn aircraft makers and airlines, or proves a mere footnote in the leadup to the eventual major business and technological changes that eventually will rock aviation, the same as any other industry. A dip in passenger numbers in Sweden is one thing. An actual cratering of an otherwise booming market for more flights is another.

Teal Group’s Aboulafia is skeptical that flight shaming will ultimately dent the growing demand for flight. “The history of humanity is more travel, not less,” he says. But if there ever were a time for aviation to have a reckoning on climate stewardship, now might be it.

“I’ve been working on these issues since 2008,” says Rutherford, “and I would say the amount of press attention, activism and airline interest in climate change — it’s like a hockey stick over the past two years.

“[Flight shame] is rolling up into a social movement,” he adds. “We’ll see where it goes.”

Staff reporter Cat Hofacker contributed to this report.

About Adam Hadhazy

Adam writes about astrophysics and technology. His work has appeared in Discover and New Scientist magazines.

“This isn’t sort of a fringe issue for the far left anymore. People are saying this is a central issue for corporate America, that we actually need to be doing something about it."

Bradley Tilden, CEO of Alaska Airlines
A busy train station hall with people sitting on circular benches and walking around. The arched ceiling and ornate chandeliers add a historic feel to the bustling scene.
European politicians are considering measures to encourage travelers to switch to trains. Below is Stockholm Central Station in Sweden, where the flight shaming movement started. Credit: Jorge Lásca
A silver train is stationed at a platform under an overhang, with another red and white train visible on an adjacent track. The platform has signs and a clock.
Trains at Gothenburg Central Station in Sweden, where air travel declined in 2019. Credit: Wikepedia
Aerial view of an Airbus A320neo flying over a body of water, showcasing the aircraft's design and the text
The Airbus A320neo aircraft are 15% more fuel-efficient than their predecessors, largely due to new Pratt & Whitney engines and airframe modifications. Credit: Airbus
A blue fuel tanker truck is refueling an airplane on an airport tarmac. The truck's fuel hose is connected to the airplane's wing. .
The aviation industry says flight shaming fails to take into account improvements in fuel efficiency among its newer aircraft. Credit: Jorge Láscar

Flight shaming’s surprising power