8 Aircraft noise pollution and greenhouse gas emissions

Zoom in on image

Photo: alexandrumagurean

Use of the airspace contributes to, among other things, noise pollution near airports and emissions of greenhouse gasses and other climate impacts from aviation. By adjusting the airspace use, both climate impacts and noise pollution can be reduced, and contribute to Norway reaching its targets and obligations in these areas.

8.1 Aviation and climate

Emissions of greenhouse gasses from domestic aviation is covered by Norway’s international emissions obligations in the Kyoto Protocol and the Paris Agreement. Emissions from Norwegian domestic civil aviation represented slightly more than 2 per cent of total Norwegian emissions in 2019, corresponding to approximately 1m tonnes of CO₂. As a result of the Covid-19 pandemic, air traffic and emissions were drastically reduced in the spring of 2020 and have remained at a low level ever since.

However, aviation impacts the climate through mechanisms other than CO₂ emissions. Air traffic contributes to the formation of condensation trails and cirrus clouds at high altitudes. The effect of cirrus clouds and condensation trails is potentially very strong and even stronger than the CO₂ effect. A common approach is to assume that the overall climate impact of aviation is 1.8–1.9 times higher than the effect of CO₂emissions alone16. However, there is considerable uncertainty in this regard and currently the additional effect is not taken into account in Norwegian or international climate policy.

The Norwegian Government’s climate policy for aviation is presented in the Climate Action Plan for 2021–2030 (Meld. St. 13 (Report to the Storting (white paper)) (2020–2021)). In this report, it is stated that the Norwegian Government wishes to facilitate a strengthened climate policy for aviation, where a carbon tax and emissions allowance are the most important means. However, more efficient use of the airspace and optimisation of landings and departures will also reduce fuel consumption and thereby CO₂ emissions. To ensure efforts from all actors, the EU is using the performance system for air navigation services as a means to ensure the shortest and most fuel-efficient flights. New technologies make it possible to increase the volume of traffic that can be managed safely within a given airspace and time frame. Norway, Sweden, Denmark, Finland, Latvia and Estonia introduced Free Route Airspace in 2016. This is an organisation of airspace that allows the airlines to no longer have to follow predefined paths, but instead follow the best possible route (paths in three dimensions) in relation weather conditions and wind, as well as the desire to fly the shortest distance possible and thereby use less fuel. Eurocontrol has calculated that the introduction of Free Route Airspace will result in a reduction of emissions from European aircraft in the amount of 10,000 tonnes of CO₂ per day (based on 2019 traffic figures). The lack of co-location of air traffic services, combined with different systems, may, however, contribute to Free Route Airspace becoming challenging to practice.

The EU’s research programme SESAR has established a project that will be able to reduce the non-CO₂-related climate impact of aviation in the upper part of the airspace by up to 10 per cent in return for an increase in costs of just 1 per cent, by adjusting the speed and altitude of airplanes.

As a further development of the regulations for SES, the European Commission has proposed to modernise the management of the European airspace and establish more sustainable and efficient airline routes. This is considered to have the potential to reduce aviation emissions by up to 10 per cent.

From a purely climate and environmental perspective, Norway should support the EU’s regulatory initiative. However, such support must be weighed against other aspects of the proposal, which, among other things, impact how the air traffic services are organised and sovereignty over national airspace, cf. Chapter 5.

8.2 Aircraft noise pollution

Noise pollution from airplanes and helicopters is linked to the use of airspace and affects many people around the airports. Traffic management and adjustment of approach and departure procedures based on a monitoring of the noise situation is an important means of reducing noise. Satellite-based approach and departure procedures offer new possibilities for choice of paths, which may remedy the situation and are increasingly being used. At the same time, more precise approaches and departures mean that noise becomes more concentrated over the same areas, rather than more dispersed.

Currently, Oslo Airport is the only airport that has its approach and departure pattern regulated by regulations out of consideration for noise. The extent to which such regulations will also become relevant for other airports in the future has not been determined. The Civil Aviation Authority of Norway has in a draft for new legislation on airspace organisation proposed a provision that grants the individual airport the opportunity to determine zones around the airport where flights are not permitted.

Going forward, both supersonic aircraft and drones in densely populated areas may cause significant noise problems that require new means, including new rules for the use of the airspace.

8.3 Balancing aircraft noise pollution and greenhouse gas emissions

The introduction of satellite-based procedures for approaches and departures can create new possibilities for directing traffic outside of areas burdened by noise pollution. Such procedures can also be used to reduce greenhouse gas emissions. In some cases, procedures resulting in reduced noise might cause increased emissions and vice versa. The announcement of satellite-based procedures can thereby, depending on location and runway direction, identify contradictions between targets relating to finance, efficiency, noise and greenhouse gas emissions.

Therefore, it is important that satellite-based approaches to the greatest extent possible combine a reduction in emissions of greenhouse gasses with the reduction of aircraft noise pollution for the airports’ neighbours. This has been introduced at Oslo Airport in the form of curved approaches and, following the good experiences there, curved approaches are now being introduced at additional airports. This is an example of satellite-based solutions that combine the two environmental challenges, emissions and noise, and that also contribute to an efficient use of the airspace.

8.4 Strategy

The Norwegian Government will:

• Continue the work on developing and utilising flight operational improvements at as many airports as possible in order to reduce greenhouse gas emissions and noise pollution for the airports’ neighbours and support the EU’s regulatory initiatives in this area.

Follow-up the research relating to the climate impacts of emissions from aviation at higher altitudes.