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AEF: Aviation and Global Climate Change (March 2000)

People living near airports have long suffered from aircraft noise, traffic congestion and air pollution. Indeed communities around airports have been concerned about these issues for years. However new evidence shows that airtravel is contributing towards a far greater threat – climate change.


Air travel is the world’s fastest growing source of greenhouse gases like carbon dioxide, which cause climate change.Globally the world’s 16,000 commercial jet aircraft generate more than 700 million tonnes of carbon dioxide (CO2), the world’s major greenhouse gas, per year. Indeed aviation generates nearly as much CO2 annually as that from all human activities in Africa. One person flying a return trip between London and New York generates between 1.5 and 2 tonnes of CO2.

The huge increase in aircraft pollution is largely due to the rapid growth in air traffic which has been expanding at nearly two and half times average economic growth rates since 1960. It is expected the number of people flying will virtually double over the next 15 years. This means increasing airport capacity, more flights, more pollution and increasingly crowded airspace.

Impacts of climate change

Scientists predict surface air temperatures are likely to rise between 1° to 5°C over the next century. This rate of warming is likely to be greater than at any time in the last 10,000 years. Although the effects will vary from place to place there is expected to be an increase in the number of very hot days and a decrease in the number of very cold days.

  • More extreme weather events – Global warming is likely to lead to more natural disasters such as hurricanes, droughts and floods. The number of major natural disasters has increased threefold since the sixties.
  • Spread of infectious diseases -The likely increase in warmer and wetter weather could enable infectious diseases such as malaria and yellow fever to spread to new areas.
  • Disappearing countries – Global warming is expected to lead to a rise in sea levels of between 15 and 95cm over the next century. Many islands and low lying coastal areas will be affected by rising sea levels and some island nations could disappear altogether.
  • Environmental refugees – Global warming could lead to the displacement of millions of people. Rising sea levels, floods and drought could make former land uninhabitable. Changing weather patterns could affect food crops and accelerate water shortages.
  • Effect on tourism – Ironically one of the industries most at risk from climate change is tourism. Many tourist destinations depend on the natural environment for their appeal to tourists. A study commissioned by the World Wide Fund for Nature (WWF) found many popular British tourist destinations would be threatened as a result of global warming.

Aviation’s Contribution to Climate Change

In 1999 the world’s top climate scientists, the Intergovernmental Panel on Climate Change (IPCC), published a detailed study of the impact of aircraft pollution on our atmosphere – Aviation and the Global Atmosphere.

The report’s findings support the following:

  • Aircraft released more than 600 million tonnes of CO2 into the atmosphere in 1990.
  • Aircraft currently cause about 3.5% of global warming from all human activities.
  • Aircraft greenhouse emissions will continue to rise and could contribute up to 15% of global warming from all human activities within 50 years.
  • Nitrogen oxides (NOx) and water vapour from aircraft engines are important greenhouse gases. Water vapour contributes to the formation of contrails, often visible from the ground, which in turn are linked to an increase in the formation of cirrus clouds. Both contrails and cirrus clouds warm the Earth’s surface magnifying the global warming effect of aviation. Together, NOx and water vapour account for nearly two-thirds of aviation’s impact on the atmosphere. Hence any strategy to reduce aircraft emissions will need to consider other gases and not just CO2.
  • An increase in the number of supersonic aircraft could further damage the ozone layer as aircraft emissions of NOx deplete ozone concentrations at high altitudes, where these aircraft would typically fly.
  • The impacts on the global atmosphere from air travel will be concentrated over Europe and the USA where 70-80% of all flights occur. Hence the regional climatic impacts of aircraft emissions over these areas are likely to be greater than predicted by the IPCC report (which used global averages)
  • Most significantly, it concluded that improvements in aircraft and engine technology and in air traffic management will not offset the projected growth in aircraft emissions. That is, we need to slow the growth in air travel if we want to reduce the growth in aircraft greenhouse gas emissions.

See publication [March 2000] below for more information.

Is the Industry Accountable?

Emissions from international aviation are specifically excluded from the targets agreed under the Kyoto Protocol. Instead, the Protocol invites developed countries to pursue the limitation or reduction of emissions through the International Civil Aviation Organisation (ICAO). To date, ICAO had not agreed any specific action, although its environmental committee is considering the potential for using market-based measures. Emissions from domestic aviation are included within the targets agreed by countries. However, the UK climate change strategy does not include any measures for tackling the domestic aviation sector. Furthermore, despite the UK Government’s stance that aviation and its users should pay for the social and environmental costs they impose, there is no duty on kerosene. The absence of a fuel tax, or an emissions based levy, allows airlines to charge artificially low fares as the cost of pollution is passed on to society and not the passenger.

A New Approach

If aviation had to meet its external environmental and social costs in full, and did not benefit from large subsidies (see AirportWatch economic briefing sheets), the growth in demand for air travel would be much slower*. Additionally, airlines would have an added economic incentive to invest in the cleanest technology available. Using market-based measures to correct these market distortions is central to delivering a sustainable aviation policy. This year, the European Commission is expected to publish a Communication on air transport and climate change which is expected to recommend the inclusion of aviation in the European emissions trading scheme, although potential roles for taxes and charges are unlikely to be ruled out.

The role of rail Over short distances (e.g. routes around 500km) air travel produces up to three times more carbon dioxide per passenger then rail. Yet nearly 70% of all flights within European airspace are less than l000km long. With over 7½ million flights within European airspace in 1998, there is a lot of scope to move short haul flights to rail. As well as less pollution, rail companies can boast faster check in times, city centre to city centre travel and less frequent delays than most airlines.

Teleconferencing Advances in telecommunications can reduce the need to travel. Tele- and video-conferencing are increasingly becoming a viable alternative to flying for many business travellers.

Voluntary ‘carbon offsetting’ may help to raise consumer awareness but does not solve the problem of greenhouse gas emissions from flying. Offsetting schemes aim to calculate the damage caused by an individual flight and allow the traveller to “pay” for the environmental damage by donating to organisations which will, for example, plant trees or invest in low carbon technology in the developing world. While offsetting sounds attractive it has several important flaws. The different schemes come to wildly different conclusions about how much carbon any given flight generates. Are some of them dramatically under-estimating the damage from flying? Does offsetting amount to a token gesture to salve the conscience, when the ethical choice is to use a different mode or not travel at all? AirportWatch does not recommend any particular carbon offsetting schemes. Instead it argues for changes to tax and charging rules to achieve consistent and fair restitution for the damage caused by flying.

A report by the Tyndall Centre for Climate Change shows fundamental contradictions between present aviation policies and climate policy. It shows how aviation growth could wreck UK and EU policies to tackle climate change. See full report or summary.

See also (below, link 1) ‘Fly now, grieve later’ – a hugely readable 46 page booklet on how to reduce the impact of air travel on climate change.

‘Fly now, grieve later’ – how to reduce the impact of air travel on climate change. [LINK]