UK Airport Expansion Threatens Net Zero Ambitions, MPs Warn

The UK's airport expansion programme is placing the country's net zero commitments in "serious jeopardy", according to a damning assessment from MPs.

The cross-party Commons environmental audit committee has warned that proposals to enlarge airports like Heathrow and Gatwick could push the UK over its carbon budgets without new safeguards.

Ministers must demonstrate how they will meet climate, environment and biodiversity targets whilst pursuing significant airport expansion, the committee says, and they must do so before any projects break ground.

The committee's report found that current government policies are insufficient to cut carbon emissions from the aviation sector in line with statutory targets, especially with rising demand for air travel expected to further jeopardise any plans to reduce national emissions.

Economic growth vs environmental impact

Prime Minister Keir Starmer and Chancellor Rachel Reeves have approved the construction of new runways at both Heathrow and Gatwick, the country's two largest airports, since Labour's victory in the 2024 general election.

For the government, these expansions are seen as key to achieving the economic growth that Starmer has sworn to deliver. 

“Heathrow is at the heart of the UK’s openness as a country,” explains the Chancellor.

"It connects us to emerging markets all over the world, opening up new opportunities for growth. Around three quarters of all long haul flights go from Heathrow. Over 60% of UK air freight comes through Heathrow. And about 15 million business travellers use Heathrow in 2023.”

The committee has challenged this approach, however.

"The government has not demonstrated that the economic growth from airport expansion provides enough benefit to outweigh the negative climate and environmental impacts it will lead to," the report stated.

The MPs involved have also criticised ministers for ruling out demand management measures such as limiting the number of flights.

When the expansion of Heathrow was first announced, John McDonnell, Labour’s MP for Hayes and Harlington, wrote on social media: “This is such a huge political, economic and especially environmental mistake that sadly I fear it will inflict an irreparable scale of damage on the government.”

Concerns over the future of SAF

The committee has raised serious doubts about how much the government's net zero roadmap relies on sustainable aviation fuel (SAF), with many MPs warning that uptake might not help cut emissions because it is not yet being used or produced on a commercial scale.

Last year Air New Zealand scrapped its 2030 decarbonisation target, blaming difficulties in securing SAF, which showed that sustainable fuels are far from the maturity required to turn the tide on climate change.

This raises questions about whether the aviation industry can deliver on its decarbonisation promises without proven alternatives at scale.

Is UK policy on aviation outdated?

The expansion schemes are expected to start before the government updates its national policy statement on airports, which was released in 2018.

The MPs said this meant the government was avoiding scrutiny and relying on an outdated policy framework inconsistent with its objectives.

Toby Perkins, the Labour chair of the committee, warns that meeting decarbonisation targets is already a major challenge.

"Expanding airport capacity is likely to make that task much harder," he says.

"Under the government's existing 'jet zero' strategy, expanding airport capacity is likely to put net zero at serious risk, unless it is accompanied by a serious strategic approach to increasing the pace of decarbonising aviation.

"Having ruled out the kind of demand management measures likely to seriously reduce emissions, ministers need to make clear what alternative tools they are willing to use to ensure targets are met."

The response of the industry

Alethea Warrington, Head of Aviation at climate charity Possible, describes the report as the final nail in the coffin for the government's case.

"The government's scrutiny committee has made it clearer than ever that airport growth is a bad option for Britain, and that the government simply doesn't have any economic evidence to justify the environmental devastation this would cause," Alethea says.

A Department for Transport spokesperson defended the plans, saying the transport secretary has launched a review of the airports national policy statement.

"We have been clear that airport expansion will only go ahead if it aligns with our legal obligations on climate change, including net zero, and we will be seeking advice from the independent Climate Change Committee to inform the review," the spokesperson said.

The government maintains that Heathrow's third runway will drive economic growth and create jobs.

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