The Civil Aviation Authority (CAA), as the UK’s aviation regulator, takes CO2 emissions into account when discharging a number of its regulatory functions.
Aircraft CO2 Emissions Certification
Article 9(2) of UK Regulation (EU) 2018/1139 brings into UK law the requirement for aircraft and their engines, propellers, parts, and non-installed equipment, to comply with, where applicable, the environmental protection requirements of Volume III of Annex 16 to the Convention on International Civil Aviation. This is further ratified in UK Regulation (EU) No 748/2012, whereby the responsibility for ensuring compliance against these environmental protection requirements for the issuance of a type-certificate (Regulation (EU) No 748/2012 Annex I point 21.B.85) and airworthiness certificate (Regulation (EU) No 748/2012 Annex I point 21.A.173), sits with the CAA. Further information regarding the specific certification Standards for Volume III of Annex 16 to the Convention on International Civil Aviation is detailed on our international policy page.
Airspace Change
The Transport Act 2000 and the Civil Aviation Authority (Air Navigation) Directions 2023 made under that Act establish the CAA as the UK airspace regulator responsible for making decisions related to changing the design of UK airspace. Section 70 of the Transport Act 2000 states that after maintaining a high standard of safety in the provision of air traffic services, the CAA must take account of several secondary factors, including any guidance on environmental objectives given to the CAA by the Secretary of State. This guidance is issued under the Air Navigation Guidance 2017 which sets out the Government’s key environmental objectives with respect to air navigation, including greenhouse gas emissions and climate change considerations. Further information regarding the CAA’s duties with respect to its air navigation functions can be found on our legislative framework to airspace change pages.
Consideration and assessment of the potential environmental impacts resulting from an airspace change proposal, including greenhouse gas emissions, is a necessary part of the CAA’s decision making process, and also enables those who are affected by the proposed airspace change to better understand the impacts of the different design options being considered. To achieve this, the CAA requires change sponsors to provide an environmental assessment that evolves through the various stages of the airspace change process.
While developing and assessing the environmental impacts of airspace change design options, change sponsors must take into account the Air Navigation Guidance 2017, including the Government’s environmental objectives and priorities as set out in that guidance. A consultation took place on proposed changes to the Air Navigation Guidance to support the airspace modernisation programme between the 25 November 2025 and the 20 January 2026.