The Climate Problem Between Industries

Two travelers board the same flight from New York to Paris. One carries only a laptop bag. The other checks two full suitcases. According to the carbon calculator published by ICAO, the UN's aviation agency, their footprint is exactly the same.

Nobody is cheating. The method simply assumes every passenger weighs 100 kilograms, bags included. But it tells us something about how climate responsibility gets divided up, and why some waste is never counted at all.

Last week in Brussels, Marie Owens Thomsen, IATA's Senior Vice President of Sustainability, opened the World Sustainability Symposium with an argument that deserves more attention than most opening speeches get. The root of global warming, she said, is the burning of fossil energy. Treating each industry as if it had its own climate problem risks "mistaking symptoms for causes." Every season brings a new villain: "One year it is aviation. The next it is beef, or cruise ships, or fast fashion, or data centers."

I agree with her. And I think her argument leads somewhere she did not take it. If organizing climate action industry by industry is the wrong frame, then the problems that fall between industries are the ones least likely to get solved. Those gaps are where my research lives.

Industries keep their own accounts

Every sector measures what it controls. Airlines track fuel burned per passenger. Fashion brands track materials, factories and sales. Each set of numbers is honest, and each one stops at the edge of its own industry.

Now think about a business traveler flying from New York to Paris with a checked bag full of clothes. To the airline, that bag is weight, and weight takes fuel. To the fashion industry, those clothes were sold long ago, and what happens to them afterward is not its concern. The traveler sees only a fee and a wait at the carousel.

Neither aviation nor fashion owns the suitcase. It belongs to the space between two industries.

That is why the two travelers from the beginning look identical on paper. The same ICAO method gives a business-class passenger a larger share of a flight's emissions, because a bigger seat takes up more of the plane. It accounts for the seat you choose, but not for the bags you check. The fuel is burned either way, but no one's packing decision ever shows up in the numbers.

Ms. Owens Thomsen warns that emissions often "migrate rather than fall" when we focus on one sector. I would add that some waste never gets counted in the first place, because it does not sit inside any sector.

The energy transition will take time, and the gaps add up meanwhile

Ms. Owens Thomsen is right that changing the energy source is the real cure. But IATA's own figures, published the same week, show how slowly that cure is arriving: sustainable aviation fuel is expected to make up about 0.8% of global jet fuel in 2026, at two to three times the price of conventional fuel.

That is not a reason to doubt the transition. It is a reason to take the gaps seriously while it happens. Every flight that takes off this decade will mostly run on fossil fuel, and whatever it carries, it carries on that fuel. The weight in the hold is not a moral failing of travelers or airlines. It is simply the result of a system nobody designed as a whole.

Fashion has its own version of the same gap. The Ellen MacArthur Foundation found that between 2000 and 2015, each piece of clothing was worn about 36% fewer times before being thrown away. Many of the clothes we pack were bought for a single trip and spend most of their life unworn. That inefficiency sits between closet and suitcase, and neither industry is set up to fix it.

Designing for the gap is not a villain hunt

My doctoral research focuses on exactly this gap, at the meeting point of aviation, fashion and how people make decisions. Through it, I am building and evaluating NOLUGGS, a service that lets travelers rent a personalized wardrobe at their destination instead of packing their own clothes.

The point is not that people should fly less, or that fashion is to blame. Both industries keep doing what they do. What changes is the link between them: the traveler stops carrying the clothes, and those clothes get worn more by the next person who needs them.

This is, I think, what Ms. Owens Thomsen's argument implies once you follow it one step further. If singling out industries is a mistake, then the useful work is not only inside each sector. It is also in redesigning the places where sectors meet, where no single industry has a reason to act on its own.

Where the argument could fail

This idea deserves the same scrutiny Ms. Owens Thomsen asks for everywhere else.

Delivering, cleaning and returning clothes has its own footprint. Whether the system as a whole ends up better depends on how it is designed, and that is something to measure, not assume. It may also stay a niche service for frequent travelers for a long time. And designing for the gap cannot replace clean energy. At best, it reduces what that energy has to carry.

These are the questions my research is testing. I do not have all the answers yet, and I am wary of anyone who claims to.

A different place to look

Ms. Owens Thomsen ended her speech hoping her audience would leave with "fewer certainties but better questions." Here is mine. If the climate problem is not really about individual industries, how many of its solutions are waiting in the spaces between them?

The suitcase is one small example. I suspect it is not the only one.

Sources

• Ellen MacArthur Foundation. (2017). A new textiles economy: Redesigning fashion's future. Read the report
• International Air Transport Association. (2026, October 14). Corporate demand could support up to 1.9 million tonnes of SAF by 2030 [Press release]. Read the release
• International Civil Aviation Organization. (2024). ICAO carbon emissions calculator methodology (Version 13.1). ICAO Carbon Emissions Calculator
• Owens Thomsen, M. (2026, October 13). WSS 2026 speech [Speech]. International Air Transport Association. Read the speech