Aviation, decarbonisation and climate change

The aviation industry has been under long-term pressure to reduce its contribution to climate change. In 2019, domestic and international aviation accounted for around 8% of UK CO2 equivalent transport emissions. While the Covid-19 pandemic has caused an unprecedented short-term reduction in demand for air travel, many within the aviation industry expect demand to recover to 2019 levels by 2023-24 and to continue to grow thereafter, though there are uncertainties.

Decarbonising aviation and “net zero”: the challenge

Under the Climate Change Act 2008 the UK is required to have net-zero greenhouse gas emissions by 2050. While the target does not explicitly cover emissions from international aviation and shipping, these emissions have been taken into account by setting aside “headroom” within the carbon budgets and the Committee on Climate Change has recommended that emissions from the UK’s international aviation be formally included in the net-zero target. In 2021, the Government set the sixth carbon budget (covering the period 2033-2037). This budget includes international aviation and shipping emissions for the first time.

However, aviation is widely recognised as both one of the most carbon-intensive forms of transport and one of the most difficult to decarbonise. This means that aviation could well be the largest contributor to UK greenhouse gas emissions by 2050, particularly if demand continues to grow.

Government policy and international initiatives

In July 2021, the Government published its Transport Decarbonisation Plan. This was accompanied by its Jet Zero Strategy consultation. The Transport Decarbonisation Plan consolidates a number of pre-existing policies across the transport sector, including, “Accelerating aviation decarbonisation, with a view to reach net-zero aviation emissions by 2050.” The Jet Zero Strategy meanwhile sets proposals for how the Government will achieve its net zero aviation target. It proposes policies that span five different measures that aim to:

• improve the efficiency of our aviation system
• accelerate the development and deployment of sustainable aviation fuels
• support the development of zero emission flight
• ensure we use markets to drive down emissions in the most cost-effective way
• influence the behaviour of consumer.

The UK Government, the EU and international bodies, and the aviation industry have proposed a number of initiatives to mitigate emissions from aviation, including:

• Market-based measures such as the United Nations CORSIA program, EU Emissions Trading System (EU ETS) and the UK ETS;
• Measures to improve the fuel efficiency of conventional aviation such as through changes to aircraft, air traffic management, airspace modernisation and ground operations at airports; and
• Measures to promote the development and use of low carbon technologies such as novel fuels (such as biofuels) and aircraft (such as hybrid-electric aircraft).

What about demand for flying?

There have also been calls for more action to limit the growth in demand for flying. Some have argued for new tax policies to discourage flying and for measures to influence individual consumer choices. At the 2020 Citizen’s Assembly on Climate Change participants “resoundingly rejected” industry projections for a future in which air passenger numbers would rise by 65% between 2018 and 2050, saying that it would be “counter-productive” for tackling climate change.

The Government and aviation industry say that there are compelling economic arguments in favour of continued growth.