THE double-decker A380, the biggest airliner the world has seen, landed at Heathrow last month to test whether London's main airport could handle the new 550-seater, due to enter commercial service at the end of this year. It was a proud moment for Britain's Rolls-Royce, the makers of the aircraft's Trent 900 engines. Rolls-Royce says the four Trents on the A380 are as clean and efficient as any jet engine, and produce “as much power as 3,500 family cars”. A simple calculation shows that the equivalent of more than six cars is needed to fly each passenger.
Take the calculation further: flying a fully laden A380 is, in terms of energy, like a 14km (nine-mile) queue of traffic on the road below. And that is just one aircraft. In 20 years, Airbus reckons, 1,500 such planes will be in the air. By then, the total number of airliners is expected to have doubled, to 22,000. The super-jumbos alone would be pumping out carbon dioxide (CO2) at the same rate as 5m cars.
That may not seem much compared with the 60m vehicles that pour off assembly lines every year—or the 1 billion vehicles already on the world's roads. But whereas cars are used roughly for about an hour or so a day, long-haul jet airliners are on the move for at least 10 hours a day. And they burn tax-free, high-octane fuel, which dumps hundreds of millions of tonnes of CO2 into the most sensitive part of the atmosphere.
Aviation is a relatively small source of the emissions blamed for global warming, but its share is growing the fastest. The evidence is strong that emissions from jet engines, including the streaks of cloud (called contrails) they leave behind in the sky, could be especially damaging. As a result, aviation is increasingly attracting the attention of environmentalists and politicians. Amid much controversy, CO2 caps and carbon-trading could soon be used to help curb aircraft emissions. Frequent flyers, free riders
Airlines are accused of having a free ride in terms of air pollution because they pay no tax on the fuel they use for international flights. Even though today's aircraft are about 70% more efficient than those of 40 years ago, concerns over emissions have grown. Despite booming demand for air travel, many airlines are losing money. Now green campaigners want people to think twice before they fly.
The clamour is particularly loud in Europe, where low-cost carriers are expanding fast on busy short-haul routes. The European Parliament will vote in July on a proposal to cap aircraft emissions and include them in the European Union's emissions-trading scheme for CO2 (called ETS). The proposal has world wide implications because it would cover all flights using EU airports—including international services.
America is deeply unhappy at the prospect of its airlines being caught up in devices like ETS. Sharon Pinkerton, a senior representative of the Federal Aviation Administration insisted, on a visit to Brussels last year, that American carriers should be exempted from the scheme. This sets the scene for another transatlantic aviation row, to add to the two bitter and long-running disputes over subsidies to Europe's Airbus and the liberalisation of air traffic between the two continents.
The airlines are growing nervous. The big international carriers represented by the International Air Transport Association (IATA) would rather Europe waited for the deliberations of a United Nations body, the International Civil Aviation Organisation (ICAO), which has set technical, legal and safety rules for more than 50 years. International aviation was excluded from the Kyoto protocol on global warming, but only on condition that, by the end of 2007, countries and airlines worked under the umbrella of ICAO to come up with a way of reducing emissions through a trading scheme.
Soon after the end of the second world war the member governments of ICAO agreed that airlines should be free of fuel taxes. Some say this was to outlaw unilateral taxes that could distort markets, but others reckon it was done to boost the fledgling airline industry emerging from the fighting. The corollary was that aviation, unlike motor traffic and other forms of transport, would pay in a transparent manner for the infrastructure and services it required—air-traffic management, landing charges, flyover rights and so on. That was supposed to take care of the external costs. But no one in those days thought much about the environment.
Counting the cost
It was not until 1999 that the United Nations Intergovernmental Panel on Climate Change (IPCC) attempted to pin down the effect of aviation on the environment. Transport as a whole was judged to be responsible for about a quarter of the world's CO2 discharges. That makes it one of the biggest sources, alongside power generation and households, as a source of the gas (see chart 1). Within transport, aviation accounts for about 13%. Its contribution to total man-made emissions worldwide is said to be around 3%.
So why all the fuss about so little? One reason is that high-altitude emissions are probably disproportionately damaging to the environment. The nitrogen oxides from jet-engine exhausts lead to the formation of ozone, another greenhouse gas. Contrails are also suspected of enhancing the formation of cirrus clouds, which some scientists think adds to the global warming effect. The IPCC estimated that the overall impact on global warming of aircraft could be between two and four times that of their CO2 emissions alone, though there is no scientific consensus about the size of this multiplier. The EU, for instance, thinks it is only two.
Click here to continue
