Heathrow expansion incompatible with climate goals, UK government advisers warn
New runway would emit as much CO₂ as the city of Birmingham, says independent Climate Change Committee
Expanding Heathrow would add as much carbon to the atmosphere as the city of Birmingham and is incompatible with the UK meeting its legally binding climate targets, the independent Climate Change Committee has warned.
The CCC on Wednesday said a third runway at Britain’s sole hub airport would release 4.5 megatonnes of CO₂ or equivalents a year by 2054 — equal to the current emissions output of the UK’s second city — even with the expected take-up of cleaner fuels and newer aircraft.
“There is no credible pathway for Heathrow airport expansion within the UK’s climate commitments under current policies,” the committee said in a report.
Heathrow already accounts for half of the UK’s aviation emissions, in part because of its concentration of long-haul flights. If expanded, the west London airport alone would produce more carbon by 2050 than farming or the electricity sector, according to modelling by the CCC — although this assumes all other industries make big cuts to emissions by the middle of the century.
Nigel Topping, chair of the committee, said: “Our key conclusion is that the government cannot expand Heathrow airport without requiring the aviation industry to clean up its emissions.”
Ministers — who have backed expansion at Heathrow as a means of boosting economic growth — had asked the CCC to study the project, as well as to look more broadly at the UK’s aviation landscape.
The committee, which advises on climate policy, found that flying emissions would breach targets without significant changes to the government’s policy — even without Heathrow’s planned expansion.
Even without a third runway — which is part of a £33bn plan by the airport and opposed by environmental campaigners — aviation emissions would rise from 37 megatonnes of CO₂ a year in 2025 to 39 megatonnes in 2050, it found.
“Heathrow just makes the problem worse,” said James Richardson, CCC chief economist.
Decarbonising aviation is significantly harder than other transport industries, with electric aircraft decades away and able to fly only short distances. There is also not enough sustainable aviation fuel to meet current targets set by the government, despite SAF already being four times more expensive than jet fuel.
In addition, SAF is produced by oil companies rather than airlines, which have complained that they are being penalised for another industry’s failure.
However, the committee argued that airlines should bear the cost of reducing emissions in the sector. Half of UK residents did not fly abroad, and a third of all international flights were taken by the top 5 per cent of travellers, classed as anyone who takes more than five round-trip flights a year, the CCC said.
“The principle is that the polluter pays,” said Topping. “There are some real fairness considerations here.”
The CCC forecast that the costs borne by the industry lowering emissions, which would run into the billions in total, would add about £150 to flights to Alicante in Spain and roughly £400 to the price of a ticket to New York.
But Tim Alderslade, head of industry body Airlines UK, warned that the suggestions would “put holidays out of reach for millions and turn the clock back to a time when flying was the preserve of the rich”.
“You can’t solve the climate crisis by pricing Britain out of the skies,” he added.
Heathrow said the report “acknowledges” that solutions existed to reduce emissions, adding: “Heathrow expansion cannot be a choice between economic growth and net zero — it must deliver both.”
The House of Commons transport committee is scrutinising the planned policy for Heathrow’s expansion, which the government needs to adopt before the airport can formally apply for planning permission.
Rachel Reeves, the previous chancellor, resurrected the proposal for a new runway and expressed an ambition for Heathrow to begin construction work in 2029, with a new runway operational by 2035, a timeline viewed with scepticism in the industry.
Green Party MP Siân Berry said the CCC’s report “could not be clearer” on the climate impacts of airport expansion and that the government now needed to “abandon its reckless plans to push through the huge mistake of allowing a third Heathrow runway”.
Silviya Barrett, from the Campaign for Better Transport, said the report demonstrated ministers should “focus on providing cleaner, more sustainable alternatives to flying”, such as long-distance trains to replace short-haul flights.
The Department for Transport said any expansion proposal “would need to align with our net zero targets” and promised to study the CCC’s report.