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Call for Evidence

Net zero aviation and shipping

The Environmental Audit Committee is launching an inquiry into net zero aviation and shipping.

Aviation and shipping pose major challenges to reducing emissions, due to their reliance on fossil fuels and since international emissions were not included in the Paris climate change agreement, requiring countries to take action. Together they account for 10% of UK greenhouse gas emissions and on current trends, aviation will be the largest emitting sector by 2050.[1]

Following the Climate Change Committee’s advice, the Government has confirmed that the UK’s Sixth Carbon Budget (covering the years 2033 to 2037) will incorporate the UK’s share of international aviation and shipping emissions for the first time.[2] The Government has said it aims to introduce the necessary legislation to include these emissions within the next year.[3]


The UK Government, 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 zero carbon fuels (electricity and hydrogen), alternative hydrocarbon fuels (biofuels) and aircraft designs (wing, airframe and engine designs).[4]

The Government’s recently published Transport Decarbonisation Strategy has pledged that new technology will allow domestic flights to be emissions-free by 2040, and international aviation to be zero carbon by 2050. The UK has a large and mature aviation sector comprising aircraft manufacturers, fuel producers and air service providers, and is well-placed to take a technological lead. According to the industry, without Government support, low carbon technologies are unlikely to develop fast enough to play a significant role in mitigating emissions before 2050.[5] The industry’s plans to meet net zero by 2050, rely on aviation funding carbon removal, the technologies for which are not yet developed at scale.[6] The Jet Zero Council (a partnership between industry and Government) has been established with the aim of delivering zero-emission transatlantic flight within a generation.

The International Civil Aviation Organization (ICAO) has developed a global offsetting mechanism, called CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation) which aims to stabilise net CO emissions starting in 2021, but it has been criticised for not requiring emission reductions.[7]

Reducing demand for air travel represents the most cost-effective method available for maintaining current emission levels.[8] 96% of the UK’s aviation emissions come from international, mainly long-haul, flights,[9] while around 15% of the UK’s population generate over 70% of the UK’s international air travel.[10] Targeted efforts towards those that fly frequently to adopt new behaviour could result in significant emissions reductions.


Most people do not realise they have any connection with shipping, unless they take a cruise, but huge quantities of consumer goods and food comes into the UK by sea. International shipping transports more than 80% cent of global trade,[11] and it is expected that global demand for shipping will increase in the next few decades.

According to the International Maritime Organization (IMO), which has responsibility for international shipping emissions, CO₂ emissions from shipping are projected to increase by up to 50% above 2018 levels by 2050 if no actions are taken.[12]

Heavy fuel oil dominates the fuel consumed by international shipping (79%), this has started to decrease but has increased the share of marine diesel oil and liquefied natural gas (LNG). The increased use of LNG in the last six years has increased methane emissions by 150%,[13] while the EU’s green fuel law for shipping is expected to allow LNG to power EU ships at the union’s ports until around 2040, which could undermine efforts to adopt low carbon fuels.[14]

The IMO has set a sector-wide goal to reduce absolute emissions 50% by 2050, compared to 2008 levels. Yet its current regulations—design and technical measures and operational measures—will not be sufficient to drive the levels of improvement required.[15] To meet its ambitions will also require new technology and innovation (such as wind assisted vessels), zero carbon fuels such as ammonia (made from low carbon hydrogen) and the development of the maritime infrastructure.[16]

The Committee is inviting written submissions on:

  • What contribution can operational efficiencies make to reduce emissions from aircraft / shipping vessels and over what timescale could these have an effect on emissions?
  • How close are zero carbon fuels to commercialisation for aviation / shipping? How effective will the Jet Zero Council be in catalysing zero emissions technologies? What role should transitional fuels such as alternative hydrocarbon fuels play?
  • What new technologies are there to reduce emissions from aircraft / shipping vessels and how close to commercialisation are they?
  • How should the Government’s net zero aviation strategy support UK industry in the development and uptake of technologies, fuels and infrastructure to deliver net zero shipping and aviation?
  • What is the most equitable way to reduce aircraft passenger numbers (e.g. reforming air passenger duty and taxes, frequent flyer levies, bans on domestic flights where trains are available, restrictions on airport capacity)? Are there any policy mechanisms that could reduce our reliance on shipping?
  • What further action is needed by the International Civil Aviation Organization and International Maritime Organization to drive emissions reductions? What can the UK Government do to drive international action on emissions?
  • How effective will the global offsetting scheme for international airlines (ICAO’s CORSIA) and the UK and EU ETS be at stimulating technology improvement and/ or behaviour change to reduce emissions from aviation / shipping?
  • How should the UK define its ownership of international aviation and shipping emissions (i.e. arrivals, departures or both) in order to include them in legislative targets?


Written evidence should be submitted through the Committee’s web portal by 3 September. Respondents need not answer all the questions and evidence need not be limited to these questions. Submissions should be not more than 3,000 words but shorter submissions are welcomed and encouraged.

We encourage members of underrepresented groups to submit written evidence. We aim to have diverse panels of Select Committee witnesses and ask organisations to bear this in mind when we ask them to choose a representative. We are currently monitoring the diversity of our witnesses.

It is recommended that all submitters familiarise themselves with the Guidance on giving evidence to a Select Committee of the House of Commons which outlines word count, format, document size, and content restrictions.


[1] Aviation is responsible for 7% and shipping 3% of national CO emissions. Parliamentary Office of Science and Technology. 2020. Climate Change and Aviation; ECIU. 2018. Exploring net zero: Aviation and Shipping

[2] HM Government. UK enshrines new target in law to slash emissions by 78% by 2035, 20 April 2021; Measuring emissions from aviation and shipping is complicated by the ownership of emissions, with most journeys being international, travelling between two or more countries and operated in some cases by companies belonging to third party nation

[3] Sixth Carbon Budget Debate - Hansard, 21 June 2021

[4] House of Commons Library. 2021. Aviation, decarbonisation and climate change

[5] Sustainable Aviation. 2021. UK aviation industry strengthens commitment to achieving net zero and launches first interim decarbonisation targets; Sustainable Aviation. 2020. Sustainable fuels UK Road-Map, February 2020

[6] Either through nature based solutions or through negative emissions technologies.

[7] Carbon Brief. 2019. Corsia: The UN’s plan to ‘offset’ growth in aviation emissions

[8] Parliamentary Office of Science and Technology. 2020. Climate Change and Aviation

[9] Climate Change Committee. 2019. Net Zero Technical Report

[10] Parliamentary Office of Science and Technology. 2020. Climate Change and Aviation

[11] International Maritime Organization. 2021. Website

[12] International Maritime Organization. 2020. Fourth IMO GHG Study.

[13] International Maritime Organization. 2020. Fourth IMO GHG Study.

[14] The Guardian. Draft EU policy to cut shipping emissions condemned as ‘disaster’, 23 June 2021

[15] IMO. Action to reduce greenhouse gas emissions from international shipping

[16] IMO. Action to reduce greenhouse gas emissions from international shipping; ECIU. 2018. Exploring net zero: Aviation and Shipping

This call for written evidence has now closed.

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