Quick fixes for air travel’s stubborn climate problem

Air travel has a big carbon problem, and efforts to tame it are just getting off the ground. New fuels and technologies often touted by the aviation industry as climate-friendly solutions appear to be many years away from wide availability.

Even so, travelers who want to reduce the harm their journeys cause the global climate have powerful tools at their disposal.

Seattle-Tacoma International Airport officials expect 2024 will be a record-breaking year, with more people flying than ever.

“Prior to the pandemic, we had nine straight years with record annual growth, and we're expecting that record to be broken again, from 2019, here this year,” said airport spokesperson Perry Cooper.

More flights mean more environmental impact.

Jet fuel from Sea-Tac Airport was responsible for up to 25% of all climate-harming emissions from King County in 2019, according to the county’s latest greenhouse gas inventory.

Rising demand for air travel makes aviation one of the fastest-growing sources of climate-damaging pollution. One cross-country flight can do as much climate damage as many people do in a whole year.

Globally, aviation causes an estimated 5% of the heat-trapping pollution added to the atmosphere each year, a percentage expected to increase as other sectors decarbonize more quickly.

Federal efforts to fight climate change are likely to evaporate with the incoming Trump administration.

A political climate favoring deregulation and fossil fuel production means that tackling the worsening impacts of air travel could mostly be up to other sectors, whether that’s businesses, local governments, or individuals.

Usually, the planetary impact of flying is mostly invisible to an air traveler. But with a tool developed by Google, travelers can pick their flights based on which does the least harm to the climate.

Travel websites including Expedia, Booking.com, Skyscanner, and Google Flights now display both the price and the planetary toll of any ticket an air traveler might buy. Site users can sort their options by cost or by carbon dioxide emissions.

Google assembled a team of experts to figure out just how much fuel is burned for a seat on nearly every commercial flight worldwide, incorporating such factors as mileage, aircraft type, and seating layout.

A recent search for flights from Seattle to New York found some were three times as polluting as others. Flying economy on Alaska Air would produce 557 pounds of carbon dioxide, while a similarly priced seat on American would release 1,803 pounds of carbon dioxide, according to Google's Travel Impact Model.

Splurge on a first-class seat, which can take up 2 or 3 times more space on a plane than an economy seat, and the personal pollution can get several times worse.

“On given flights, the difference between an economy carbon footprint versus a first class one is massive,” said Andrew Chen with the energy think tank Rocky Mountain Institute and a member of Google’s advisory panel.

Since September, Google Flights results have also included Amtrak service to the same cities. Rail travel is usually less polluting than flying, especially with the multiplier effect of engine exhaust released into the upper atmosphere. When air is cool and humid, water from jet exhaust can condense to form heat-trapping clouds that double the climate impact of a flight.

Dan Rutherford, a researcher at the International Council on Clean Transportation and an advisor to Google, said Google’s team is working to incorporate the impacts of airplanes' condensation trails into emissions estimates. For now, Google’s estimates understate the damage high-altitude exhaust causes by about half but are useful for making comparisons between flights.

According to the International Council on Clean Transportation, on average, a traveler can expect to shave nearly one-fourth off a typical flight’s impact by picking a more-efficient flight and nearly two-thirds off the impact of the dirtiest flight on that route.

A Google spokesperson declined to be interviewed, referring KUOW to the company’s press releases and outside advisors. Those advisors say the overall goal is to bring transparency to a harm that is usually hidden and help travelers make better choices.

“Aviation is not in itself evil. It's the climate impacts of aviation that we have to address,” Chen said.

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drawback of any kind of individual, voluntary solution to a global problem is that some people and businesses will adopt it and some won’t.

In November, the Northwest’s largest producer of jet fuel, the BP refinery in Cherry Point, Washington, halted its plans to start producing up to 10 million gallons annually of so-called “sustainable” jet fuel from biomass feedstocks instead of petroleum, as first reported by Cascadia Daily News. A BP spokesperson did not respond to interview requests.

Seattle-Tacoma International Airport alone dispenses nearly 700 million gallons of jet fuel annually.

In December, the International Air Transport Association said non-petroleum fuels made up just 0.3% of global jet fuel production. The airline industry lobby called the less-polluting sector’s growth “disappointingly slow.”

“Currently, technologies to reduce emissions from specific flights are pretty nascent, so it definitely does pay for those of us who fly to choose airlines and choose flights that are more fuel efficient,” Rutherford said.

Air travelers had mixed reactions when asked whether they would pay more for less-polluting flights.

“So this is my big contribution to global warming and greenhouse gasses, truly,” woodworker and bicyclist Sam Adler said while waiting for a flight home to Seattle.

He said if there was a less-polluting option, he’d take it.

“I would definitely pay more, and I would definitely pay more in taxes for a high-speed rail system along the West Coast and the East Coast,” Adler said.

Systems engineer Felicia Kaylor, on a business trip to Seattle from Alabama, said she does think about the impact of flying but wasn’t sure if she would pay more to pollute less.

“Maybe? I think the cost of flying is already pretty expensive, personally,” Kaylor said. “I think the average person, they would want to see lower prices. I don't think they would care necessarily about the environmental impact.”

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limate concerns have led some major employers to cut back on air travel.

For more than a decade, Microsoft has charged an internal carbon tax on business travel to discourage unnecessary petroleum use and help pay for the company’s carbon-reduction efforts. In 2025, Microsoft plans to boost that tax to $100 per metric ton of carbon dioxide, the equivalent of 98 cents per gallon of jet fuel.

The University of Washington has a goal to lower employees’ air travel 5% by 2025, though, unlike some universities, it has not spelled out methods to actually achieve that goal.

The University of California-Berkeley instituted a carbon tax on its business flights — $10 per domestic flight and $25 per international flight — and reports cutting its air travel emissions 19% from 2019 to 2023.

Some University of Washington faculty and staff are trying to boost their school’s ambition when it comes to doing less harm. An advisory committee is creating a program to reduce the institution’s flying and its impacts.

“None of us are proposing that we eliminate flying,” political science professor Jamie Mayerfeld said. “What we're proposing is that we become more thoughtful about the flying we do and make decisions about when to fly, taking into account the climate harms associated with flying.”

Mayerfeld, whose research focuses on political theory and human rights, made a promise to himself that he would cover climate change at least a little in every course he teaches. He said he has cut back his own flying, both professional and personal, and has sworn off flying to conferences.

“Flying really epitomizes the problem of climate injustice,” he said. “It involves a very small number of the world's population contributing disproportionately to greenhouse gas emissions. It's a small number of people who do a lot of flying.”

Mayerfeld says he recognizes that flying can be hard to avoid for activities like field research and professional development.

“Academics spend a lot of time flying to conferences and flying to workshops. Some of that activity can be replaced with online workshops, or perhaps regional workshops, which involve traveling over shorter distances,” he said.

Academic associations including the American Philosophical Association, the American Sociological Association, and the Middle East Studies Association now alternate conferences between in-person and virtual. Others have started holding “multi-hub” hybrid conferences, with simultaneous local gatherings connecting virtually for keynote speeches and panels.

“It's possible to have online conferences that are imaginative, creative, that accomplish a lot, and that are better than the kind of online conferences some of us might have experienced in the past,” Mayerfeld said.

Though online events are rarely as satisfying as meeting in person, they do have a big benefit beyond avoiding pollution.

They expand the number and types of people who get to participate, including those who can’t afford to fly — or think the planet can’t afford it.