And in the UK, the independent, publicly funded Climate Change Committee (CCC) has advised government that no credible pathway exists within national net zero commitments under existing policies to expand London Heathrow Airport, which CCC says produces around half of all UK aviation emissions.  

T&E’s September 2026 study showed that expanding Heathrow will add 2.4mn tCO₂ in annual emissions by 2050, rising to 4.5mn tCO₂ when the expanded airport reaches full capacity in 2054. This increase alone represents 5% of the UK’s total remaining permitted carbon emissions under the 2050 legal budget.

Nigel Topping CMG, Chair of the CCC, said that emissions from flying are projected to rise, even without Heathrow expansion, and the UK does not currently have a credible plan to bring them down. Since 1990, aviation emissions have more than doubled, while overall UK emissions have halved.

In Europe, Spain’s aviation emissions are increasing faster than those of any other major nation. Spain plans to expand 12 of its busiest airports at the same time, including Madrid, Barcelona, Palma and Málaga. In 2025, these four airports accounted for 66% of Spain’s departing flight emissions. Expanding these four airports will add 35mn tCO₂ in emissions, which T&E says is equivalent to Portugal’s total annual carbon output. Expanding Madrid airport alone will generate 23mn tCO₂ over 25 years, surpassing Spain’s total aviation emissions in 2025.

In Portugal, Lisbon and Porto airports generate 80% of national aviation emissions. To stay on track, Portugal must reduce aviation emissions by 12% annually to meet its national climate targets. Constructing a new airport in Lisbon will add 18mn tCO₂ in emissions, equal to half a year of Portugal’s total carbon output, according to T&E data.  

To counter these trajectory trends, T&E has called for airport-specific carbon limits to ensure capacity expansion does not override climate legislation.  

Meanwhile, in advice requested by the UK government on the draft Heathrow Expansion National Policy Statement, the CCC urged ministers to enforce the statutory 2050 net zero target.

‘Our advice today is clear: ‘Heathrow expansion is not currently compatible with the UK’s net zero target,’ Topping said. ‘Government needs to ensure that the aviation industry takes responsibility for the emissions it creates and bears the costs of decarbonisation. Those conditions do not exist today.’

To resolve this shortfall, the CCC set out a net zero framework applying the ‘polluter pays’ principle across all UK flights. The CCC framework also states that engineered CO₂ extraction would need to account for 36% of the aviation sector’s required emission cuts by 2050 under the CCC model, while lower passenger demand growth would need to deliver 24% of reductions. Technical efficiency improvements would supply 20% of emissions cuts and sustainable aviation fuel (SAF) adoption the remaining 20% of required sector reductions. In contrast to technological removals, the CCC excluded tree planting from aviation targets, reserving natural land carbon sinks for absorbing agricultural methane emissions.

Requiring airlines to fund decarbonisation will inevitably raise ticket prices for consumers. CCC modelling indicates a return ticket from the UK to Alicante, Spain, will increase by £150 by 2050, while a return ticket from the UK to New York will rise by £400 under the polluter-pays model. While higher ticket prices are expected to moderate consumer demand for flights in the coming decades, the committee notes that 50% of adults in England do not fly abroad in any given year.

‘This summer’s extreme weather has brought the impacts of climate change into sharp focus,’ Topping said. ‘Every tonne of greenhouse gas emissions makes those impacts worse. That's why it's so important the right policies are put in place now to fully address aviation emissions.’

Reflecting this stance, the citizen panel for the CCC Seventh Carbon Budget rejected the idea of using public funds for airline decarbonisation. Panel members stated that non-flying citizens should not cover airline fuel transitions or direct air capture operations. In response, the committee recommended that ministers assess policy options to address financial impacts on lower-income households.

The UK’s Labour government previously acknowledged that expectations regarding electric aircraft, rapid efficiency gains and SAF uptake under the 2022 Jet Zero Strategy were unrealistic. Looking ahead, ministers plan to publish an updated UK aviation decarbonisation strategy in 2027, with a final UK government decision on Heathrow expansion expected by 2029, says the committee.

In the interim, the CCC advised ministers to establish contingency policies if SAF production or engineered removal projects suffer from deployment delays. It also urged ministers to coordinate with European partners and the International Civil Aviation Organisation to prevent carbon leakage across international routes, stating that commercial risks regarding future flight demand must sit with private investors rather than consumers or taxpayers.