Aviation Greenhouse Gas emissions and Noise emissions

Position Paper by T&E on behalf of the International Coalition for Sustainable Aviation*





Aviation has many impacts on the environment, including local air pollution (NOx, HC, and toxics), climate change (CO2, NOx, contrails, SO2) and noise. According to the IPCC Special Report on Aviation and the Global Atmosphere, aviation currently represents 3.5% of total human-induced radiative forcing (this is as much as the current contribution of the UK to global warming) and could represent as much as 15% by 2050 if no measures are taken to reduce these emissions, even after accounting for expected technological and operational improvements.  Carbon dioxide emissions from aircraft, which account for around 37% of aviation’s climate impact, are predicted to more than double between 1990 and 2015.  However, other greenhouse gas emissions from aircraft, most notably contrails and NOx, are equally important and contribute around two thirds of the industry's current climate change impact (IPCC, adopted in April 1999).


In order to combat climate change, the developed countries and economies in transition reached an agreement, under the Kyoto Protocol, to reduce their greenhouse gas emissions to about 5% below 1990 levels between 2008 and 2012. The same major industrialised nations that signed this agreement are also Contracting States of ICAO.  While domestic aviation emissions are accounted for in these countries’ emissions totals, emissions from international aviation are not (see Kyoto Protocol, Decision 2/CP3).  Furthermore, as Article 2.2 of the Kyoto Protocol states, the Parties should, “pursue limitation or reduction of greenhouse gases… from aviation…bunker fuels, working through the International Civil Aviation Organisation …”.


In this context, ICAO, under Resolution A32-8 Appendix F, requested its Committee on Aviation Environmental Protection (CAEP) “to study policy options to limit or reduce the greenhouse gas emissions from civil aviation”.  CAEP was requested to focus on an en-route levy or a fuel levy to address global emissions, and on other market-based options such as emissions trading.


Aircraft noise continues to be the environmental issue of most concern to airport neighbors. While most aircraft have become progressively less noisy at source over the decades, this has not been matched by a reduction in annoyance. This is largely because community reaction to noise is determined not only by the intensity of noise events, but also by their incidence, especially when they occur at sensitive times such as night. There is increasing scientific evidence on the need to protect people from exposure to high levels of aircraft noise.  Recent studies, most notably the internationally peer-reviewed report of the Dutch Health Council on The Impact of Large Airports on Health (1999), demonstrate a link between aircraft noise and sleep disturbance, health and learning acquisition.


According to the World Health Organization’s (WHO) Guidelines on Community Noise (2000), serious annoyance can be expected above 55 dBA Leq (16 hour) during the day, and moderate annoyance above 50 dBA Leq (16 hour). However, to avoid sleep disturbance, noise levels in bedrooms should not exceed 30 dBA (8 hour) at night (45dBA LAmax).  Furthermore, 73 Government Ministers from 57 nations have also adopted the WHO Charter on Transport, Environment and Health (London, 1999).  This makes recommendations about standards, policies and guidelines, and measures to develop future improvements and compliance strategies.


CAEP previously set a goal to prevent an increase in the number of people impacted by noise after completing the phase-out of Chapter 2 aircraft. Around many airports, communities have an expectation, often based on promises made by the industry or regulators, that noise levels will not worsen after 2002. However, the analyses presented to CAEP 5 show that, without any ICAO action, the number of people exposed to 55 DNL in the non-exempt regions will increase from 8.57 million in 2002 to 10.41 million in 2020 (unconstrained capacity). This increase is smallest in the North America region (5.92m to 6.13m), but more significant in Europe (2.23m to 3.17m) and Japan, Australia and New Zealand (0.42m to 1.13m).



Our Position


Greenhouse Gas Emissions:
We believe that the market-based measures developed in CAEP’s working groups will only achieve limitation/reduction in emissions if the countries can agree on targets for emissions reductions. There is also a need to put in place enforcement and control mechanisms. From an environmental stance, it is important that these measures are applied worldwide. However, at this stage, we accept that developing nations, who do not have a historic responsibility for these emissions, should be exempt.


Voluntary agreements, if pursued, should be developed by the industry, without additional resources or effort from CAEP/ICAO. Military aircraft emissions can be omitted for the time being.


We urge the member states of ICAO to support the following recommendations:

§         ICAO should establish a CO2 target consistent with the Kyoto Protocol (5% below 1990 levels) to be achieved by the first budget period (2008-2012);

§         ICAO should enable the introduction of market-based mechanisms to address CO2 emissions in a two-tiered manner:  (1) by instituting an emissions charge, on both the LTO and cruise cycle, by the 34th Assembly at the latest; and (2) achieving the full 5% below 1990 emissions level target, either through a continuation of the charge and/or, after the adoption of the Kyoto Protocol guidelines and mechanisms, the introduction of an open emission trading program that would begin no later than the start of the first budget period (2008) (in this latter case, the majority of  reductions in the EU should be done through policies and measures);

§         To control all other aircraft greenhouse gas emissions, ICAO should establish: (1) a NOx cruise standard and (2) a market-based mechanism to control all emissions during the cruise phase, including potentially weighting CO2 emissions to fully reflect the total radiative forcing (i.e., global warming potential) attributable to the sector; and

§         ICAO should inform COP7 of how emissions will be reduced and by how much. If no appropriate solutions are decided by the next ICAO assembly, COP7 should adopt a decision on how to resolve the allocation issue, followed by a work plan and immediate implementation plan.


Noise Emissions:


The recommendation of CAEP 5 to improve the stringency of aircraft noise certification standards by a cumulative margin of 10 dBA, compounded by the absence of any agreement on phase-out, will not be sufficient to prevent a worsening in noise climate around many airports, especially in Europe. 


We strongly urge that:

·         Immediate steps are taken to support the introduction of a new noise standard that improves stringency by a cumulative margin of 14 EPNdB compared to Chapter 3 with effect from 2002 (to include a minimum improvement at each of the three certification points of 4 EPNdB).

·         Transitional rules be established for the phase-out of existing Chapter 3 aircraft which are unable to meet the new noise standard: aircraft that are within a 5 dBA margin of the existing Chapter 3 standard should be phased-out within a period of 4 years (by 2006); all other aircraft unable to meet a Chapter 4 standard to be phased-out by 2020 at the latest.

·         ICAO should develop a long-term objective for aircraft noise reduction.  A cumulative reduction of 30 dBA compared to Chapter 3 by 2012 is a realistic target, and one that is consistent with some internal industry targets.  This will (a) help manufacturers and airlines to plan for the future with a degree of confidence, especially in respect of R&D and design programmes, and (b) allow for continual improvements in noise performance.  Further improvements in certification should encourage, and keep pace with technological advances and be subject to regular review.

·         Support be given to the concept of a balanced approach to reducing noise, providing effective targets are set: the objective should be to reduce the number of people currently exposed to daytime noise levels in excess of 55 dBA Leq (with nobody exposed to daytime aircraft noise levels above 65 dBA). In no circumstances should any increase in the number of people exposed to 55 dBA Leq be permitted.


April 2001




* ICSA, the International Coalition for Sustainable Aviation currently consists of Aviation Environment Federation, Center for Clean Air Policy, Coalition for Clean Air, Dutch Society for Nature and Environment (SNM), Friends of the Earth-Europe, German League for Nature and Environment (DNR), GermanWatch, T&E, World Wildlife Fund-US.