Green Liberal Democrats Opposed to Airport Expansion Proposals
The UK government officially approved Heathrow’s long-debated third runway on the 29th of January, and almost a month later, we are awaiting a decision on a second Gatwick runway from Transport Secretary Heidi Alexander.
Chancellor Rachel Reeves claims the decision will encourage much-needed economic growth for the UK.
However, this decision risks exacerbating environmental damage and public health concerns, whilst offering questionable economic returns.
We, Liberal Democrats have long opposed the third runway for many years, committed to limiting aviation growth to stay within climate targets and focus on economic models which promote a focus on human capital.
Liberal Democrat Spokesperson for Transport and MP for Twickenham Munira Wilson MP, alongside four other Lib Dem MPs whose constituencies will be negatively impacted by the expansion, wrote to the Transport Secretary, to reject the proposals.
Even their own members are against it – with both Net Zero Secretary Ed Miliband and Mayor of London Sadiq Khan opposing it it as well as the former Labour shadow chancellor John McDonnell who criticised the government's backing of a third runway at Heathrow, saying it is "such a huge political, economic and especially environmental mistake".
Liberal Democrats in London have fought against the decision for many years, and written council motions which vow to support the Mayor and voice concerns over its risks.
Economic Justifications
The government claims Heathrow expansion will boost the economy but think tanks such as the New Economics Foundation found that the arguments are flimsy, at best. Dr Alex Chapman recognises the current contribution aviation provides to our economy – but argues it cannot be used to justify further expansion.
Firstly, the benefits will be heavily concentrated in London and the Southeast, rather than driving national growth. The jobs Reeves claims will be created – (up to 100,000) could displace jobs elsewhere, deepening regional inequalities and may draw investment away from regional airports like Manchester and Birmingham. Additionally, the New Economics Foundation (NEF) found that increasing air capacity has been generating fewer and fewer jobs over time and real-terms wages in air transport are falling faster than in any other sector.
At the same time, air travel is changing—business flights are declining, and tourism spending no longer guarantees economic growth. Reeves’ claims that increasing capacity which will lower fares and bring in more flights is potentially a misplaced presumption and ignores current trends. Even if her argument holds some merit, it remains an economic gamble that fails to account for the need for sustainable, inclusive, and regionally balanced growth.
Environmental Risks
There is no doubt that our economy needs a boost, but green economists, campaigners and politicians alike have come out in droves to ask the question –growth: at what cost?
The Chancellor has made it very clear that she will pursue growth above all, and even specifically stated in Davos (2025 World Economic Forum) that if forced to, she would choose it above climate action. This flies in the face of the many promises from the government to “end climate chaos” with Kier Starmer himself saying “there is no more important challenge than the climate crisis”.
Climate Change Committee states that no airport expansion is within climate targets and carbon budgets. Additionally, a court appeal in 2020 found the decision to be ‘unlawful’ as they breach the UK's commitments in the Paris Agreement to reduce greenhouse gas emissions. The NEF found that all the benefits of the government’s plans for clean power plan such as grid decarbonisation will be cancelled out if the Heathrow, Gatwick and Luton airport expansions go ahead.
Furthermore, we Liberal Democrats know that these are not mutually exclusive. The green economy grew 9% in the UK in 2023 – against the rest of the economy which saw a 0.1% rise in growth. The evidence overwhelmingly shows the green economy booming. It is important to note that not only do these decisions totally disregard social and public health considerations, but this area of London is also worst affected by air and noise pollution and will exacerbate respiratory illnesses and reduce quality of life for local communities.
Alternative economic strategies which benefit the environment and centre social good must be promoted. Deputy Leader of the Liberal Democrats Daisy Cooper says "The single biggest lever" to help turbocharge the economy, would be "negotiating a new UK-EU trade deal with a bespoke customs union at its heart". Alongside this, nationwide investment in green infrastructure and public transport—a proven driver of economic growth in countries around the world—could deliver long-term prosperity while cutting emissions and improving quality of life. The London School of Economics (LSE) also recommends that the UK expand its green economy, citing its potential to increase productivity, create jobs, and strengthen social and human capital.
The Viability of Sustainable Aviation Fuels
If you ask Reeves, she will argue that the expansion plans are aligned with the UK’s net zero strategy. Her claims are largely reliant on significant advancements in sustainable aviation fuels (SAFs), with a target for SAF to make up 10% of jet fuel by 2030. However, the Climate Change Committee deems this target unrealistic, and private fuel investors and developers, including Shell, note that airlines are reluctant to transition to SAFs at such a rapid pace due to high costs and complex production processes. Without strict mandates, prices are unlikely to fall.
SAFs for aviation remain far from ready, and demand is minimal—current usage stands at just 0.1%. Even reaching 10% by 2030 and 22% by 2040 hardly signals a true path to net zero. A report by Safe Landing demonstrates that SAFs are being used as a justification for airport expansion, rather than an actual climate solution - the real focus should be on reducing fossil fuel reliance and jet usage. Moreover, scaling up SAF production is incredibly resource-intensive, further undermining its credibility as a clean alternative.