Commercial aviation has striven to reduce noise and emissions, but politicians are stepping up calls for greater effort
Commercial air transport has made far greater strides in reducing its environmental impact than any other mode of transport, but instead of being congratulated, aviation is still the favourite bête noire of government. This is the view of Giovanni Bisignani, director general of the International Air Transport Association (IATA), who warns that any future regulations need to consider the need for growth in air travel. But the battle lines are being drawn, especially in Europe, where some governments want to impose anti-growth measures in the name of reducing aircraft pollution.
Limiting the environmental impact of aviation is dealt with at an international level – chiefly by the International Civil Aviation Organisation’s (ICAO) committee on aviation environmental protection (CAEP). The Montreal-based committee consists of governments, industry groups and green pressure groups and every three years issues priorities and recommendations. Adherents of the consensus approach of CAEP can point to some successes. Firstly, the noise footprint of modern jets is around 75% less than those 30 years ago, largely thanks to ICAO-brokered noise targets. Secondly, today’s new aircraft are 70% more fuel-efficient than the first jets and, finally, authorised levels of oxides of nitrogen (NOx) have been reduced by 36% since they were identified as a problem in the early 1980s.
Improving gains
Of these gains, the improved fuel efficiency is key, since each tonne of Jet-A combusted in aero engines produces 3.5t of carbon dioxide. Carbon emission is still the largest concern for environmental groups around Europe, says Jeff Gazzard, co-ordinator for the Green Skies Alliance of conservationist pressure groups. Transport is one of the largest non-natural sources of carbon and aviation, despite only accounting for 12% of the sector’s CO2 emissions (compared with 75% for road transport), vegetation cannot absorb airborne emissions as it does at ground level.
But aviation has drastically cut its CO2 emissions and when civil aircraft are compared with other modes of transport, aviation’s green credentials emerge: Airbus says the global aircraft fleet has an average fuel efficiency of 5.6 litres/100 passenger kilometres (1.5USgal/62 miles), assuming payloads of around 85%. The average fuel consumption for the global car fleet is 5.5 litres/100 passenger kilometres (based on an average of 1.64 people in cars). Airbus head of environmental affairs Philippe de Saint-Aulaire says the new A380 will have a fuel efficiency of 3 litres/100 passenger kilometres fully loaded and would have to drop to a load factor of 63% to drop to the fuel consumption levels of even the most modern cars, which average 4.7 litres/100 passenger kilometres.
Furthermore, aircraft fuel consumption is much better than that of buses and is around half that of high-speed trains once electricity generation is taken into account, Jean-Cyril Spinetta, chairman and chief executive of Air France says.
Yet despite these gains, environmental groups still want much more drastic action. Tim Johnson, director of the International Coalition for Sustainable Aviation (ICSA) US-European green umbrella grouping, says Airbus’s fuel consumption figures are unrealistic comparisons as the short-haul journeys on which aircraft compete with ground transport produce more emissions, as more damage is done on take-off and landing.
The main concern, says Johnson, is that future forecasts predict increased fuel efficiency of around 1-2%, while air transport is expected to grow at 5% a year, creating more pollution in absolute terms.
Around the world, especially in Europe, the green lobby is arguing for taxes, curbs and quotas all designed to stop the growth of air transport. For example, the European Green Party, which with various allies, has held around 40 seats in the European Parliament for much of the past two decades, wants to overturn the Chicago Convention, which it considers “unethical” because it prohibits a tax on fuel used in aviation or maritime applications.
For the environmentalists, the international system is too slow and deliberately exploited by airlines as well as governments of heavy polluters or oil producers to stall progress towards more severe curbs on aviation growth, says Gazzard. “The current system is good at establishing a bottom line, but it’s not good at establishing solutions to problems,” says Johnson. For example, as the seventh session of CAEP in 2007 has nothing on the agenda to tighten emissions rules the debate will not start until the eighth, which is due to report in 2010. This would see implementation by 2015 at the earliest. “By the time those aircraft enter the fleet, even with the most stringent reductions, it will be decades before any effect will be seen,” he says.
There are signs, however, that some governments have been persuaded to consider opting out of the international system and imposing “solutions” of their own. Industry bodies fear that regulations for one part of the world, be it a country or a trading bloc, will discriminate against carriers based there. However, as demonstrated by France’s President Jacques Chirac, who called for a $1 per ticket tax on airline tickets to pay for aid to the developing world at the World Economic Forum Summit in January in Davos, Switzerland, there is still a perception among politicians that aircraft are more polluting than other forms of transport and need to be punished, according to British Airways outgoing chief executive Rod Eddington.
Cash cow
Bisignani believes it is because aviation is a cash cow for governments, so they would rather keep the industry’s progress towards greener aircraft undisclosed. “In Germany the government makes €11 [$13.5] profit for every 1,000 passenger kilometres, but pays out €55 for every 1,000km of rail,” he says. Figures for France are even starker: €67 goes into the tax revenue for every 1,000 passenger kilometres against €78 in subsidy for each 1,000km of track, he adds.
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What can be done? Science is fairly sure of carbon dioxide’s effects. Produced by the burning of fossil fuels, CO2 traps heat from the sun that would normally be reflected off the Earth’s atmosphere into space. There has been a 30% increase in atmospheric CO2 recorded since the industrial revolution. Oxides of nitrogen (NOx) are produced by high temperature burning in the engine and are thought to trigger chemical reactions that produce ozone. Ozone is generally produced by NOx at altitudes below around 36,000ft (11,000m). NOx also traps radiative energy and so adds to global warming. However, question marks remain over the effect above 36,000ft, where NOx emissions could produce methane, cooling the Earth. Also, scientists are undecided on the effect of ozone, as its lifetime is relatively short. Condensation trails (contrails) are caused by warm moist exhaust meeting cold air at high altitude, causing exhaust particulates to be frozen in ice crystals. Contrails reflect some solar radiation, cooling the Earth, but can also reflect rising thermal radiation. It is unclear whether one effect cancels out the other. Contrails can join to form cirrus clouds, although scientists are not unanimous on their effects. |
But in these countries, as well as others, there are fears that the continued growth in air transport will lead to more damage and so curbs to growth are being sought, says Gazzard. Green Skies argues that the international talking shops are inadequate to bring the fast action needed to halt expansion, adding that commercial reasons rather than concern for environmental protection led to the impressive drops in fuel consumption and emissions so far. There will be no financial incentive for cash-strapped airlines to act as quickly with future hot topics, such as hydrocarbon particles, so action is needed at a local or regional level, he argues.
Those representing airlines and aircraft manufacturers are trying behind the scenes to ensure that moves to impose new punitive measures on air transport are resisted in favour of internationally agreed standards, as has been the case so far. A good example of how this works in practice is the balanced approach to airport noise quotas, says de Saint-Aulaire. Local governments seeking to reduce noise levels are bound to consider local land planning, aircraft operational procedures and town planning before going for the easy option of imposing quotas on airlines, he says.
However, green groups have little confidence that international consensus will be appropriate for all future issues facing aviation. Some, such as the effect of water vapour contrails on cirrus cloud formation at high altitude and hydrocarbon particle emissions, would seem to fit well within the global framework, while other subjects such as the effect of aviation on the local air quality around airports and disposal of dangerous chemicals are seen by many as local issues. Tony Houseman, environment attaché at the Aerospace and Defence Industries Association of Europe (ASD), says manufacturers fear this kind of compartmentalising of environmental legislation. “If people get frustrated with ICAO they may look to national governments or regional groupings like the European Commission to move faster,” he says.
Many, for example, would like to see a tax on kerosene. However, since aviation fuel tax’s illegal status is unlikely to be overturned anytime soon, the European Union cannot impose a tax even on flights within its borders. Instead, it will recommend the inclusion of aviation within its existing emissions trading scheme, through which polluting companies buy and sell carbon credits for all emissions above a permitted level. The EC says details still need to be defined, not least how to allocate the carbon produced by multinational airlines operating in several countries, but there is a will to include flights into the scheme by 2007, says the EC’s environment directorate general.
Rush to regulate
The rush to regulate, acute in some European countries with a large Green lobby such as Germany and Sweden, may lead to economic discrimination for those airlines operating under the stricter rules, says Houseman. There is also a danger of regulating in areas which are ill-defined and far from fully understood scientifically. The EC published findings in 2003 from its TRADEOFF study into aircraft emissions and found that whereas some aspects of environmental impact, such as CO2 emissions, are well understood, there is poor knowledge in areas such as contrails, cirrus clouds, water vapours and methane emission and only slightly better data in NOx and carbon monoxide discharge.
Given the long product lead times in aviation, de Saint-Aulaire says rushed regulation without scientific certainty could be more damaging than beneficial, as it could lead to opposing technological outcomes. For example, the A380 has a larger diameter fan causing a heavier nacelle drag and 1.2% heavier fuel consumption and thus CO2 emissions to meet London Heathrow airport’s QC2 nighttime noise restrictions. John Green, chairman of the UK Royal Aeronautical Society’s science and technology subgroup, says this is an example of the conflict between local and global rules that are likely to become more frequent. “Increasingly local requirements will define aircraft,” he says.
The next big issue that looks likely to fall foul of this conflict is local air quality around airports. Several local authorities in Europe have signalled that they are considering a charge on aircraft based on NOx levels at airports and in 2008 new EU targets come into force.
But, Pierre Bry, vice-president of marketing for CFM International, says this is missing the point, since aircraft are not the culprits. A study in Paris in 2002 showed that only 8% of NOx measured was attributable to the combined effect of Charles de Gaulle, Orly and Le Bourget with the bulk of the remainder due to road transport. Andreas Hardemann, manager of aviation environment policy at IATA, says that while operational procedures such as continuous descent and using ground power instead of auxiliary power units have been promoted, the problem is more to do with ground vehicles and cars at airports and on-site power generation at major hubs. “The easy way out is for local governments to introduce charges for aircraft NOx emissions without examining the other factors,” he says.
Similar to the noise/CO2 trade-off, reducing NOx also poses problems for powerplant engineers. Since 1981, lessening NOx in engine exhaust has been a priority for ICAO, but the best way to do so is to lower the engine pressure ratio, says Bry. To achieve low NOx a small, cool, low-resistance engine was needed, which would reverse all the gains in efficient engines, he says. Until technologies such as multipoint fuel injection, lean burn premix combustors and water-cooled engines are developed, achieving CAEP targets of a further 12% reduction from new engines from 2008 will involve some trade-off with CO2 emissions.
Further reductions
However, as Airbus points out, if European regulators go it alone on new emissions targets, as some Green groups want, the targets could be even more ambitious. For example, the EC’s Advisory Council for Aeronautics Research in Europe has set a further halving of fuel burn by 2020 as a theoretical target, which even new design aircraft such as the A380 and the Boeing 787 will struggle to meet.
There is a lack of understanding amongst regulators, however, which leads to such unrealistic targets. Before the 1990s, some lobby groups wanted to ban aircraft flying above 36,000ft (11,000m) for fear that emissions in the troposphere aided depletion of the ozone layer. But an Airbus-led atmospheric research project measuring ozone from 1990 proved the hypothesis to be false. Without the research, which collected 140,000h of data from 2,500 real flights, potentially damaging and pointless legislation might have been passed, says de Saint-Aulaire. Airbus has expanded the trial to study contrails and their effect on the creation ofcirrus clouds in a bid to head off future legislation before the scientific facts are better known.
Further reductions in emissions can also be achieved in the medium term through better use of air traffic management, and in the longer term by alternative fuels. The industry must hope governments take these gains into account before acting to tax aircraft out of the sky.
JUSTIN WASTNAGE/GENEVA & LONDON
Source: Flight International
