UK’s share of international aviation emissions reached its highest level ever in 2024
25th June, 2025
PRESS RELEASE: Aviation Environment Federation analysis of 2024 provisional carbon emissions data for the UK [1] suggests that hopes that 2019 would be the peak year for aviation emissions have been dashed. Total international aviation bunker emissions were 36.06Mt in 2024, compared to 36.02Mt in 2019 (please note this figure does not include domestic aviation emissions) [2].
The previous government’s Jet Zero strategy (JZS), launched in 2022, set out a vision for reducing emissions from aviation, with the government at the time saying: “We want 2019 to be remembered as the peak year for aviation emissions”. Between 2020 and 2023, air traffic and emissions fell dramatically as a result of the Covid pandemic, but in 2024 air travel rebounded and emissions from the sector look set to carry on rising. Demand has continued to grow in 2025, with both passenger and flight numbers up by 2% in the first 3 months of the year vs the same period in 2024.
Our analysis of the data coincides with the launch of the Climate Change Committee’s Progress Report, which is being released on the 25 June. The CCC’s figures reflect that aviation emissions are not falling in line with their Balanced Pathway, saying that “aviation emissions are now above both the emissions expected in the JZS and where we expected our Seventh Carbon Budget baseline to begin in 2025”. The CCC warns that the continued increase in emissions from aviation has partially offset some of the recent gains made in the electricity supply and industrial sectors, and “could put future targets at risk”[3].
Further analysis of the DESNZ data reveals that in 2024, the number of international passengers was higher than in 2019. However, due to a drop in domestic passengers, overall there were 5 million fewer passengers through UK terminals in 2024. This suggests that the increase in emissions is being driven by larger planes flying further on international routes [4]. The average international flight distance has also increased from 2019 to 2024 (2,766.5kms in 2019 to 2801.4kms in 2024).
The Jet Zero strategy envisages emissions reductions would come from a number of policies, including the deployment of “sustainable” aviation fuels (SAF), greenhouse gas removals, carbon pricing, efficiency gains and the development of new technologies. The Climate Change Committee recommends that by 2030 the total (including domestic and military) UK aviation emissions need to be on a downward trajectory, reaching 35.4Mt by 2030; this is just 4 years away. But there has been little progress on delivering greenhouse gas removals or new technologies, and the levels of SAF are well below what is needed.
Airport expansion is incompatible with reducing emissions
The emissions figure is significant because aviation is set to become the highest emitting sector of the entire British economy by 2040 according to the CCC. Yet the government is currently inviting proposals for the expansion of Heathrow Airport, by far the biggest emitting airport in the country. The expanded airport may open in 2035, right in the middle of Carbon Budget 6, when emissions must be firmly on a downward trajectory.
In 2024, the government granted permission to London City Airport to expand, in April this year it gave the green light for Luton Airport to expand, and in the autumn a decision is expected on the expansion of Gatwick airport.
These figures come as no surprise to anyone tracking the slow progress towards decarbonising aviation. While progress is occurring in other sectors, notably in electricity generation and road transport, we seem to be awarding aviation a special licence to emit.”
Tim Johnson, AEF Director // tim@aef.org.uk // +44 7710 381742
SAF delivery even lower than expected
AEF has also been exploring data related to the scaling up of SAF. We recently revealed that Climate Change Committee modelling on future SAF uptake actually predicts that 38% less SAF than required will be available in 2040. The UK’s recently launched SAF mandate requires 22% of fuel to be SAF by that date, however, our figures suggest that there will be a shortfall of 1.1 million tonnes.
There has also been little progress in scaling up of the most sustainable types of SAF, e-fuels, which are made from recovered CO2 and green hydrogen. The CCC estimates that by 2030, around 500,000 tonnes of synthetic aviation fuel is needed per year. Currently there are no domestic e-fuel plants at final investment decision (FID) in the UK. While a number of plants are making progress – for example Arcadia Fuels is currently trying to launch an e-SAF plant at Stockton-on-Tees – the expected amounts it will produce are insufficient to meet the mandate – just 68,000 tonnes of fuel a year.
ENDS
Footnotes:
[1] Published by the Department for Energy Security and Net Zero (DESNZ) [LINK]
[2] This does not include domestic aviation emissions. AEF has made repeated requests to DfT to provide a breakdown by sector of UK domestic transport emissions in 2024, but we have not been able to confirm this figure. For reference, the figure for 2019 was 1.36Mt
[4] 2019 international passenger numbers 255,303,973, domestic 45,023,463; 2024 international passenger 256,106,643, domestic 39,222,054