The cost of dealing with CO2 emissions as Heathrow expands should be passed onto airlines, according to advice to government from an independent UK climate body which is calling for legislation to force airlines to clean up their act.
A third runway for Heathrow has been on the cards for nearly a quarter of a century, with plans for it twice approved since it was first proposed in 2003. Today’s administration has an ambition to open the facility by 2035, with Chancellor John Healey insisting the “economic case stacks up and will help bring growth.”
The present blueprint, costed at around £33 billion (around €38.5 billion) would see a 3,500-metre runway and new terminal constructed to the northwest of the airport’s current footprint, demolishing 750 homes across at least three villages and requiring the M25 motorway encircling London to be diverted.
The expansion is intended to boost flight capacity at the UK hub by around 58%, handling up to 756,000 flights per year, instead of 480,000. The UK’s Department for Transport claims any Heathrow expansion will align with net zero goals, and pointed to government investment of £219 million in sustainable aviation fuel production and a further £43 million in cleaner technologies “to support greener aviation, while expansion could deliver around £40 billion to the economy and support up to 60,000 local jobs.”
But environmental champions, including Transport & Environment (T&E) and the Climate Change Committee (CCC), say the increase in flights would exceed the UK’s carbon budgetsand put 2050’s net-zero target out of reach.
To avoid that scenario, Nigel Topping, the chair of the CCC, said the UK government needs to introduce measures to make the aviation sector responsible for managing its emissions within climate thresholds, through increasing the proportion of “sustainable aviation fuels” (SAF) they use, and by paying for the permanent removal and storage of carbon from the atmosphere.
“The government cannot expand Heathrow airport without requiring the aviation industry to clean up its emissions. Therefore, the government should legislate policies that require the aviation industry to fully address all of their emissions by 2050, either directly or by purchasing engineered removals. The polluter-pays principle must apply,” Topping said.
Heathrow third runway should be stopped unless the government can credibly guarantee aviation emissions will be cut to zero by 2050, @theCCCuk chair Nigel Topping says. pic.twitter.com/aPtx3W1RwS
— Climate Centre (@ClimateCentreUK) September 16, 2026
But aviation stakeholders such as industry group Airlines UK implied that cost would eventually be passed onto consumers, “pricing Britain out of the skies.” Chief Executive Time Alderslade said the CCC’s suggestion would “put holidays out of reach for millions, turning the clock back to a time when flying was the preserve of the rich”. Instead he called for “affordable SAF … more direct routes and scaled up removals.”
Meanwhile, a spokesperson for Heathrow said: “Heathrow expansion cannot be a choice between economic growth and net zero – it must deliver both” and added it would “continue working with government and partners across the aviation sector to ramp up today’s proven technologies, while examining options for how the billions of pounds passengers already pay in carbon taxes can be used to support this.”
