Emissions from UK flights are rapidly returning to pre-pandemic levels, with CO₂ pollution from aviation on track to reach a record high this year.

The increase means the sector may breach a key plank of the government’s Jet Zero strategy, which pledged to not surpass 2019 figures on the way to reaching net zero emissions from aviation by 2050.

Several airlines are already emitting more than ever before, according to analysis from the campaign group Transport & Environment (T&E) based on UK and EU carbon reporting and other flight data.

It estimates that Ryanair emitted 13.5% more CO₂ in 2023 than it did in 2019, with easyJet up by 4.8% and Jet2.com up by 26.3%. British Airways was still by far the UK’s most polluting airline, although its emissions remain 18% below 2019 levels.

Last year, 940,000 flights departed from UK airports, emitting a total of 32 mn tonnes of CO₂, 89% of 2019 levels, according to T&E. It said there had been remarkable levels of growth in comparison to 2022 alone, with long-haul flight emissions 28% higher, and that the data suggested aviation emissions could reach a record high in 2024.

BA, Ryanair and easyJet have announced continued planned expansion of between 7% and 9% for 2024.

Although the newer planes with lower fuel consumption ordered by airlines such as Ryanair mean they have boasted of lower emissions for each passenger, the rapid growth in traffic means their overall pollution figures are growing inexorably.

As well as warning that the UK government’s Jet Zero roadmap towards more sustainable aviation risks going off course well before 2050, T&E urged policymakers to reconsider how airlines are taxed given the limitations of the emissions trading scheme (ETS).

The UK’s ETS only covers flights wholly within the UK, the European Economic Area and Switzerland. That means that long-haul flights in and out of the UK – accounting for the majority of emissions – escape without charge while domestic or European flights pay for each tonne of CO₂.

British Airways, whose emissions grew an estimated 25% in 2023, pays less under the ETS than easyJet or Ryanair, despite producing almost three times as much CO₂ because of its long-haul network. Virgin Atlantic, which only flies to destinations outside Europe, paid nothing at all in ETS. Wizz Air paid £34.23 for each tonne of CO₂ emitted, according to T&E.

BA would have paid another £350m annually under an ETS system that included long-haul flights, T&E added.

Ryanair itself has called for an overhaul of the system, demanding the extension of the UK and EU ETS to all flights. However, reform of the scheme to include long-haul flights has proved difficult in the past, with the US and China threatening to derail previous EU attempts to find a fairer global solution.

Future additional emissions from all flights will be liable for offsets under the Corsia system agreed by the UN body, the International Civil Aviation Organization (ICAO), before the pandemic – but it is not mandatory worldwide until 2027 and campaigners fear the impact will be negligible due to the likely cost to airlines.

T&E has called for a kerosene tax. Matt Finch, the UK policy manager at T&E, said: “Some airlines had their most polluting year ever in 2023, and there is a good chance that many more will get that badge of dishonour in 2024.

“The UK government is apparently committed to charging polluters to help pay the clean-up costs they cause, but it is wilfully ignoring charging airlines, despite their growing climate impact. That’s the directly opposite approach they’re taking to the nation’s drivers at the petrol pump.”

The Department for Transport was approached for comment.

A BA spokesperson said: “As this report recognises, [our] emission levels are below where they were in 2019. We are proud of the 10% reduction in our carbon intensity we’ve delivered since 2019 and are working hard towards our target of net zero by 2050.”