Aviation and climate change

Aviation is a major contributor to climate change. It is both one of the most carbon-intensive forms of transport and one of the most difficult to decarbonise.

How significant are the UK’s aviation emissions?

In 2022, the UK’s domestic and international flights produced 29.6 million tonnes of CO2 equivalent emissions (MtCO2e). This is around 7% of total UK greenhouse gas emissions. The independent Climate Change Committee (CCC) projects that aviation’s proportion of UK greenhouse gas emissions will increase from 7% in 2022 to 9% in 2025, 11% in 2030 and 16% in 2035. This is because as emissions from some other sectors decline, stable aviation emissions will make up a larger proportion of the total.

The UK has committed to reaching net zero greenhouse gas emissions by 2050 to address and limit the effects of climate change. The UK has also committed to the Paris Agreement of the United Nations Framework Convention on Climate Change (UNFCCC), which includes setting and meeting national emissions targets with the aim of limiting global temperature increases to below 1.5˚C.

Domestic aviation emissions already count towards the overall UK net zero target. International aviation emissions will be included within the achievement of the UK net zero target from the sixth carbon budget (2033) onwards, placing a greater emphasis on the need to decarbonise aviation to meet the UK’s emissions targets.

The government pathway for net zero, as set out in the Net Zero Strategy (2021), accepts that there may be some headroom for growth in aviation up to 2030, but that the sector will need to see a major reduction from this point onwards. Both the government and the CCC note that fully decarbonising aviation by 2050 will be impossible, and that residual emissions in 2050 will need to be accounted for by greenhouse gas removals and offsets in order to meet net zero emissions.

What are the UK Government’s policies for decarbonising aviation?

The most recent overarching strategy for aviation decarbonisation is the Conservative government’s 2022 Jet Zero strategy. This committed to a range of measures including the rollout of Sustainable Aviation Fuel (SAF), aviation systems efficiencies, promotion of zero-emission flight technology, and the use of national and international carbon markets and offsets.

The CCC said that the Jet Zero strategy was “high risk due to its reliance on nascent technology – especially rapid Sustainable Aviation Fuel (SAF) uptake and aircraft efficiency savings”.

The Labour government has not signalled any deviation from the Jet Zero strategy. In December 2024, it said it was “considering [its] wider approach to decarbonising aviation”, continuing the previous government’s support for sustainable aviation fuel, and was “committed to airspace modernisation which is expected to have environmental benefits”. Airspace modernisation is the government’s ongoing project of simplifying flight routes over the UK.

Are there plans for expanding UK airports?

There are several UK airports that have live expansion plans. Two large expansion applications are due for a ministerial decision in 2025, at Luton airport and Gatwick airport. In January 2025, the government said it would also welcome proposals for a new runway at Heathrow airport. In February 2025, the government said it was “minded to approve” Gatwick expansion but extended the deadline for a final decision.

In 2024, the CCC recommended that the government “stop airport expansion” without first creating “a UK-wide capacity management framework”.

In its December 2024 response to the CCC, the government did not agree to such a capacity management framework, and said it “recognises a role for airport expansion where it provides economic growth and is compatible with our legally binding net zero target and strict environmental standards”.

What is Sustainable Aviation Fuel?

One measure outlined in the 2022 Jet Zero strategy was to increase the production and use of SAF in the UK. SAF is a broad term for lower carbon alternatives to conventional aviation kerosene produced by various methods. SAF is not a zero carbon option, though estimates suggest that emissions from SAF are up to 80% lower than emissions from conventional aviation kerosene over the course of the fuel’s life cycle.

There are two main parts of the government’s policy to create a SAF market:

• a SAF mandate, in place since 1 January 2025, which focuses on guaranteeing a demand for SAF. Under the mandate, SAF should provide 10% of aviation fuel for flights within and departing the UK by 2030.
• a revenue certainty mechanism which focuses on SAF production and supply, which is expected to be the aim of a forthcoming Sustainable Aviation Fuel Bill, announced in the July 2024 King’s Speech.

The government has also provided grant funding for SAF, as well as innovative future technologies, such as hydrogen or electric planes through the Advanced Fuels Fund. Electric and hydrogen aviation technologies are at an early stage and currently only considered options for shorter haul distances, meaning SAF is likely to be a long-term fuel option.

What international action is being taken to decarbonise aviation?

International action is particularly important for aviation decarbonisation, as all international flights involve more than one nation. Unlike UK rail or road decarbonisation, any policy to decarbonise aviation requires alignment and agreement between multiple governments.

There are a number of international policy measures to mitigate aviation emissions. These include the use of emissions trading schemes (ETS) in some regions to cap the total volume of emissions and to require airlines to surrender tradeable allowances against these emissions.

Some aviation emissions fall within the scope of the European Union ETS; specifically, CO2 emissions from flights within the European Economic Area (EEA) and departing flights to Switzerland and the UK.

Similarly, some emissions are within the scope of the UK ETS; CO2 emissions from flights within the UK, between the UK and Gibraltar, and flights from the UK to the EEA and Switzerland.

In addition to ETS, the UN International Civil Aviation Organisation (ICAO) has developed its Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA). CORSIA is a global market-based mechanism designed to offset international aviation emissions. It aims to ensure that increases in emissions above a baseline year are balanced by offsets, which ICAO says will result in “carbon neutral growth”.

The UK is one of 129 countries participating in CORSIA. On 16 December 2024, the government published a draft statutory instrument and consultation on the UK’s implementation of CORSIA, which closed on 24 February 2025.