Why it doesn’t stack up ‘to be minded to approve’ a second Gatwick runway

Letter to Sussex MPs from Chair, CPRE Sussex.

Dear Sussex MP,

Given the recent indication by the Secretary of State for Transport that she is ‘minded to grant’ an expansion of Gatwick Airport from one runway to two, on top of a significant expansion of Luton Airport and a potential additional runway at Heathrow, I am writing to share my deep concerns about the reliance of both the government and the aviation sector on a Jet Zero strategy that relies on fundamentally flawed assumptions to align aviation growth and climate change policy.

In particular, there is an unrealistic expectation of what so-called ‘Sustainable’ Aviation Fuels (SAF) can, in practice, deliver over the coming decades.

The documents attached show how awkward the situation is and how much almost magical thinking the sector seems to be going through, including in that, the current government:

1. The roadmaps to jet zero. These show clearly that jet zero is not net zero with over 19Mtonnes carbon dioxide to be removed by some unknown means. Decisions to approve expansion based on such roadmaps cannot be sound or responsible in my view. Roadmaps to net zero in aviation 20250321_0001   
2.   The extant policy position on airport expansion in “Flightpath to the Future”: Although the doc is from the last government it is an ambition to expand only if commitments are met. Flightpath to the Future – airport expansion and climate change_20250321_0001
3. The problems with “Jet Zero” policy measures (the policy issue are repeated in the Jet Zero One Year On report). Most of these have problems with delivering them in a timely way. The sector simply cannot deliver on SAFs or fleet modernisation fast enough to help make a Gatwick expansion decision sound. On SAFs in particular the supply chain problems seem very big. There are no SAF plants – certainly not five in the UK that are up and running. No one knows whether they will work or deliver the projected carbon savings in practice. No one knows if the materials can be found to meet potential demand with damaging consequences (say to agriculture). Worse of all SAFs make no difference at all to tail-pipe emissions from aircraft – in fact they make things worse by moving carbon from the terrestrial to the atmospheric compartment of the planet; the exact opposite of what needs to happen. Jet Zero policy and Gatwick decision linked issues_20250321_0001
4. ZeroAvia: The government (technically the last one) are saying in Jet Zero; One Year On that ZeroAvia have achieved flight with a hydrogen electric powertrain. This is not the case as the press material from Zero Avia make clear. Their small aircraft is still experimental and only one of two engines is of the new type . The Chancellor and others are wrong to claim otherwise. Unconventional power trains like ZeroAvia_20250321_0001
5. Myths about aviation need busting – selected pages from the APPG report in 2023. APPG Net Zero Myth Busting Report July 2023 _20250321_0001

I hope this material is of interest. The issues here are complex and I would be happy to discuss with you and/or colleagues in your team to offer more explanation and distillation if needs be. I fully appreciate the challenge aviation faces (having worked in innovation myself) . But it will help no one to base a dash for growth on false promises.

I am genuinely concerned that the Secretary of State’s final decision on Gatwick expansion later this year should be soundly based on evidence. I have worked on such matters with three Chief Scientific Advisors (King, Beddington and Walport)  and admit to being staggered by the approach being taken in aviation and towards airport expansion. The sector needs to up its game. Handing them economic advantages with no certainty of environmental returns will not deliver the kind of sustainable development we all badly need.

I would be grateful if you could raise questions with the Secretary of State as to the credibility of the Jet Zero Strategy, and how airport expansion – in general, and at Gatwick specifically – can be compatible with Net Zero commitments, given the lack of credible evidence that aviation can decarbonise at the necessary pace.

Yours sincerely,

Prof Dan Osborn (Emeritus Professor of Earth Sciences, UCL)

Chair, CPRE Sussex