One way to curb emissions while expanding Heathrow could be by throttling the very thing its sprawling infrastructure would built to serve: passenger demand. 

That’s what Aviation Environment Federation’s policy manager Celeste Hicks told MP Scott Arthur last week during the UK’s Transport Select Committee meeting on the environmental impact of expanding the UK’s busiest airport.

Aviation is 2.5% of global carbon emissions, but its contribution to warming is actually higher due to non-CO2 factors such as contrails. UK law sets out an economy-wide binding target of net zero greenhouse gas emissions by 2050, compared with 1990 levels. 

Hicks was joined on a panel by Lois Pennington, a research associate at The Tyndall Centre for Climate Change Research at the University of Manchester, and Alethea Warrington, who is head of aviation, energy and heat at the climate charity Possible.

They argued that carbon removal technology and SAF are far from the scale they need to be to help aviation curb emissions. 

Hydrogen and electric aircraft are expected to have only a marginal impact on aviation emissions by 2050, as noted by the Department for Transport itself in the 2026 UK Aviation Forecast, even in scenarios that are optimistic about technology. Warrington said efficiency gains will be marginal as operations are already highly optimized, and Pennington pointed to slow shift to SAF. The 2026 UK Aviation Forecast cut SAF share from 50% to 30% in 2050. 

The UK also revised its aviation emissions scenarios upwards. In its 2022 aviation strategy, it was forecast the industry would be left with 37 megatons of CO2e emissions that it needs to offset or remove by 2050. The 2026 forecast sits at 41.1 megatons, showing the aviation industry is already off course. In the scenario where technology does scale, the new forecast still sits 8.83 megatons higher than previously thought, at 28.1 megatons. 

So aviation can’t count on the tools it’s been touting thus far, making demand management an important tool. 

The question is how to taper demand equitably — something that blunt carbon taxes aren’t built for. They can be priced too low to incentivize decarbonization, and costs could be passed on to the consumer.

Critics argue that higher fares price people out of flying, and question why it should be only the wealthy who can afford a summer holiday. 

Warrington suggested a frequent flyer tax instead, given 1% of the world’s population is responsible for 50% of aviation emissions, according to a New Economics Foundation report co-produced with Possible.

The idea is that a levy would be used for green investment and to finance the transition. The New Economics Foundation research found a levy could raise €63.6 billion (around $73.4 billion) in net tax revenues and cut 21% of carbon emissions. 

The proposal is not new. IATA’s then-director general Willie Walsh responded to the Global Solidarity Levies Task Force’s suggestion last year, saying at the time that “the airline industry is an economic catalyst, not a cash cow.”

And when a similar idea was floated in 2019 by Imperial College London for the Committee on Climate Change, trade body Airlines UK told CNBC that it could risk harming British competition and that the country should instead focus on becoming “a world leader in new innovation and the many exciting developments around aircraft and engine technology, sustainable aviation fuels and the new emerging carbon markets.”

IATA and Airlines UK did not immediately respond to Skift’s request for comment. 

Check out my full reporting over at Skift, and, as ever, feel free to say hi at [email protected].