Heathrow’s proposed third runway cannot be approved under current climate policies, the government’s Climate Change Committee (CCC) has said. The committee says expansion could proceed only if the aviation industry pays for cleaner fuels and machines designed to remove carbon dioxide from the air.

CCC chair Nigel Topping said Heathrow expansion was “not currently compatible” with the UK’s net-zero target. He said airlines should take responsibility for the emissions they produce and bear the costs of reducing or removing them, arguing that those conditions do not currently exist.

The committee’s report cannot itself block the runway. It is instead calling for legislation that would transfer the long-term clean-up costs of aviation from the government to the industry. The CCC estimates that the additional expense could eventually raise the price of a return flight to Alicante by about £150 by 2050, and a return trip to New York by about £400 in today’s prices. Spread over 25 years, however, it said the annual increase would amount to a few pounds per year.

The CCC says carbon-removal machines would need to cut more than a third of the expansion’s emissions by 2050. It also acknowledges that very little of the technology currently exists at scale, with credible plans covering only 1% of the engineered removals needed by the late 2030s. Once expanded, Heathrow would produce more carbon dioxide than any other single sector of the economy by 2050, according to the report.

The Department for Transport said ministers would carefully consider the CCC’s advice alongside responses to an ongoing consultation. Any expansion would need to align with national climate targets, the department said, while claiming the £33bn project could generate about £40bn for the economy and support up to 60,000 local jobs. Heathrow said expansion and climate goals were not a choice and that it would deliver both.

Airlines UK rejected the proposed approach. Its chief executive, Tim Alderslade, said the transition to net zero had to remain affordable, arguing that higher costs could put holidays beyond the reach of millions. He called for airspace reform and expanded production of sustainable fuels, while saying the aviation sector could not develop carbon-removal technology alone. Researchers and local opponents remain concerned about emissions, noise and air pollution; about 750 homes are expected to face demolition if the runway is built. A formal Commons vote is expected later this year.