Green groups urge climate advisers to rule out airport expansion

Open letter to the government’s independent climate advisors, the Climate Change Committee, from two key environmental organisations lays bare the incompatibility of airport expansion – including a third runway at Heathrow – with UK climate targets  

Friends of the Earth, alongside Greenpeace, has written to the government’s climate advisers warning that airport expansion, including a third runway at Heathrow, cannot be made compatible with the UK’s climate commitments.  

In their letter, the groups are urging the Climate Change Committee (CCC) to make this unequivocally clear in its upcoming advice to the government as part of a review of the Airports National Policy Statement (ANPS). The CCC’s input was requested by the Transport Secretary in November last year. The review will guide any final decision on the expansion of Heathrow Airport and will determine how aviation emissions are assessed.

The CCC’s advice to the previous Conservative government had ruled out any airport expansion as incompatible with UK climate targets [4]. However, in their most recent update to government, their advice had shifted, advising that airport expansion was in line with targets in certain circumstances, citing the rollout of government climate schemes and ambitious technological improvements [5].  

In the letter, Friends of the Earth and Greenpeace argue that the CCC’s case for further airport expansion relies on:

• Unrealistic assumptions regarding the speed and implementation of new climate initiatives
• The failure to take already-approved airport expansion into account regarding passenger numbers
• Over-dependence on still-developing technologies that have yet to demonstrate their scalability

Regarding unrealistic assumptions, the environmental groups point out that the CCC’s calculations rely heavily on the rapid roll out of heat pumps and electric vehicle incentives. However, both schemes have seen significant political opposition which is hindering their progress. 

The government has previously rejected the CCC's own call to ban the installation of new gas boilers in homes after 2035 and went further by significantly scaling back the support for heat pump installations in their new Warm Homes plan, released last month. The roll out of electric vehicles has also been slowed by ministers weakening the sales requirements of car manufacturers. 

On passenger numbers, the groups say the CCC also needs to adequately account for the cumulative impact that already-approved airport expansions will have on the number of people taking flights. Developments at Gatwick, Stansted, Luton, Bristol and London City airports alone could add more than 60 million additional passengers a year. These alone would bring passenger numbers above the CCC’s forecasting for 2035. A third runway at Heathrow would add a further 66 million passengers, far exceeding the total passenger numbers in the CCC’s scenario planning for not only for 2040, but also 2050. 

The groups’ third concern hinges on the over-reliance on uncertain and still-developing technologies in the CCC’s calculations. These include Sustainable Aviation Fuels (SAF), bioenergy with carbon capture and storage (BECCS) and direct air carbon capture and storage (DACCS). All of these technologies have repeatedly failed to meet questions of affordability and scalability. Even the government itself admits there are risks to scaling up SAF production both domestically and globally to the level required to meet the targets set out in the SAF mandate.  

Friends of the Earth and Greenpeace are calling on the CCC to uphold its statutory role under the Climate Change Act to provide independent, fact-based advice to help inform the government’s approach to airport expansion. The groups maintain that this is the body’s duty regardless of the government’s position. 

Niall Toru, senior lawyer at Friends of the Earth, said: 

“The CCC’s credibility depends on it calling the science as it is, regardless of what ministers may want to hear. We urge the CCC to ensure its recommendations remain independent and evidence based.

“The reality is that a third runway at Heathrow is incompatible with our legally binding climate targets. The numbers only work with wishful thinking and technologies that don't currently exist at scale – and may well never.” 

Dr Douglas Parr, Policy Director of Greenpeace UK, said: 

“Twenty years ago, when the government wanted to build more dirty coal plants, they described their proposals as ‘CCS-ready’. But of course, Carbon Capture and Storage wasn’t ready, and still isn’t.  

“Now that they want to build new runways, we’re told that their planes’ unabated carbon pollution will be magicked away through a combination of CCS, Direct Air Capture and Sustainable Aviation Fuel. But none of these technologies are ready for the job either, and may never be. 

“The Climate Change Committee are the UK’s top carbon accountants and, while aware of the realities, are being confronted with a government line of possible-but-unlikely carbon savings being equivalent to actual carbon savings. In financial accounting, this would be fraud, and allowing it in carbon accounting would risk a lot more than just money.” 

ENDS 

For more information and interview requests contact the Friends of the Earth press office on 020 7566 1649 or email [email protected].  

Notes to editors: 

1. Friends of the Earth and Greenpeace sent its letter to the Climate Change Committee on Wednesday 18 February 2026. The letter can be read in its entirety on Friends of the Earth’s website.  

    

2. The government wrote to the CCC seeking advice on the ANPS review and wider role of aviation in meeting cross-economy carbon budgets, specifically referring to the Heathrow expansion, on 25 November 2025 | Letter to the Climate Change Committee: engagement during Airports National Policy Statement review - GOV.UK 
   The CCC has been asked by government to advise on:
   1. Proposed amendments to climate sections of the ANPS 

   2. The “wider role of aviation in meeting cross-economy carbon budgets in the context of Heathrow expansion”, building on its advice for the Seventh Carbon Budget (CB7)

       

3. In 2020 the CCC advised government on the sixth carbon budget (2033 to 2037). It recommended no net expansion of UK airports to ensure aviation can achieve the required pathway for UK aviation emissions (p.176). In its 2023 progress report the CCC noted that since making this recommendation airports across the UK had increased their capacities and continued to develop capacity-expansion proposals. The CCC’s view was that “This is incompatible with the UK’s Net Zero target unless aviation's carbon-intensity is outperforming the Government's pathway and can accommodate this additional demand”. It recommended no airport expansions until a UK-wide capacity management framework is in place to annually assess and, if required, control sector CO2 emissions and non-CO2 effects (p.267). It repeated this recommendation in the 2024 progress report (p.96).  

    

4. For more information, see CB7 advice of February 2025 (p.230).