This chapter summarises the latest scientific understanding on the main environmental impacts of aviation, namely noise, air quality and climate change. A robust knowledge on these issues is crucial as a basis to inform policy-making assessments and decisions.
To mitigate adverse effects from aircraft noise on EU citizens’ health, the World Health Organisation Europe recommends reducing aircraft noise levels below Lden 45 dB and Lnight 40 dB.
Air pollutant emissions from aviation have increased within the EU. Effective action requires better characterisation of aviation’s specific contribution compared to other sources of emissions, especially on particulate matter.
In addition to mitigation measures from aircraft operations and airport activities, airport surface access plans (e.g. good public transport links) can also effectively reduce air pollutant concentrations.
The growth in aviation CO2 emissions was accelerating prior to COVID-19, with almost half of global CO2 emissions between 1940 and 2019 having occurred since 2000.
In 2018, the estimated Effective Radiative Forcing (ERF) from non-CO2 emissions accounted for more than half (66%) of the aviation net warming effect, although the level of uncertainty from the non- CO2 effects is 8 times larger than that of CO2.
Environmental certification standards already exist for aircraft engine non-CO2 emissions, including NOx and nvPM, and further mitigation policy options are being considered.
Where specific mitigation measures incur trade-offs between CO2 and non-CO2 emissions, a robust assessment methodology is essential to ensure an overall reduction in climate impact. In addition, ‘win-win’ options that reduce both simultaneously should be supported (e.g. appropriate sustainable aviation fuels).
In 2022, the IPCC 6th Assessment Report noted that immediate, rapid, and large-scale reductions in greenhouse gas emissions are needed to limit warming to 1.5°C and that the avaition sector is still in the earlier stages of adaptation to increased climate hazards.