Aircraft eat up oil little else on earth. A family of four flying to the USA would cause more emissions than their entire domestic energy use in a year, and about twice the emissions from a car travelling 12,000 miles.
On present tends, aviation is going to continue to gobble up oil and emit pollutants. It currently accounts for just over 3.5 percent of total CO2 emissions worldwide. The Intergovernmental Panel on Climate Change estimates that by 2050 emissions from aircraft could be responsible for up to 15 percent of total global warming produced by human activities.
Despite this, the UK Government is committed to a programme of aggressive aviation growth. Its Aviation White Paper, published in December 2003, aimed to cater for a near-trebling of passengers by 2030. It suggested that as many as five new runways would be required - that is, the equivalent of at least two new Heathrows.
This level of expansion is incompatible with the Government's target to cut emissions. A recent report by the House of Commons Environmental Audit Committee commented: "if aviation emissions increase on the scale predicted by the Department for Transport, the UK's 60 percent carbon emission reduction target.....will become meaningless and unachievable."
So, what is to be done? For the foreseeable future there is no realistic alternative to oil for running aircraft. The two possible alternatives are both problematic. Although hydrogen-based fuel would not produce carbon dioxide, it would lead to the forming of two and a half times more water vapour than kerosene, thus causing a substantial greenhouse effect. A report by the Royal Commission on Environmental Pollution, published in 2002, concluded, "it follows that hydrogen can be discounted as a way to reduce the climate change impacts of air travel, at least for many decades."
The other alternative fuel being talked about is derived from biomass. But this raises considerable environmental problems. Its potential CO2 savings are unclear as energy is required to create sulphur-free kerosene from biomass sources and a considerable amount of land and fertilisers are required to grow biomass.
If alternative fuels are to be ruled out, is it possible that technological advances will result in aircraft gobbling up less oil? Experts estimate that there are likely to be fuel efficiency improvements of 15 percent over the next 20 years, with a 25 percent improvement possible if what is technically feasible can be fully exploited. It is also estimated that, if the typical aircraft reduced its cruising speed by 25 percent, there would be an average saving of around 7 percent in fuel used.
These technical advances will almost certainly be wiped out by the predicted growth in aviation. In the UK the Government expects passenger numbers to almost treble over the next 30 years. Across the world aviation is expanding. But this growth is not inevitable. It is being artificially stimulated by the tax concessions received by the aviation industry. Aviation fuel is tax-free and, in most countries, there is no VAT on aviation transactions. This is the main reason why we can fly to Prague for the price of a pint at our local. Equally, aviation doesn't pay the full price of the social and environmental costs it imposes on society. A fairer tax system would cut the rate of passenger growth and possibly over time produce an actual reduction in air travel.
And yet people do want to travel. On business, for leisure and to visit family. But the ability to travel and meet with each other also plays an important role in cementing together many protest organisations, including the growing anti-globalisation movement. There are ways, I believe, by which we can cut air travel without placing excessive restrictions on travel itself.
Firstly, rail needs to be promoted as an alternative means of travel. High speed rail is winning passengers from the airlines. During the first ten months of 2004, EuroStar attracted 68 percent of the traffic between London and Paris; and 64 percent on its Brussels route. The story of the TGV high speed lines in France is similar. The TGV on average is attracting 90 percent of the traffic where the train journey is two hours or less; 65 percent of the people at three hours; and a credible 40 percent at four hours. If the network were to be expanded, German towns such as Cologne, Dusseldorf, Frankfurt and Stuttgart, could be brought within three hours of Paris. Milan and Bilbao would just be three and a half hours away from the French capital.
For journeys of around three hours rail is winning out -that is a distance of about 500km by high speed train. Given the fact that 45 percent of trips in European airspace are less than 500km in length, there is considerable scope for change. But this is not an argument for covering Europe with high speed rail as it is not a problem-free means of transport. It does use up enormous amounts of electricity. Its huge construction costs can result in resources being diverted from more environmentally-friendly and socially-equitable local transport projects. It does encourage people to make ever-longer journeys. However it is true that a limited network of high speed lines across Europe, linked into reliable local rail and bus services, could provide an attractive alternative to air travel.
Secondly, individuals need to examine their own flying habits. A 40 year-old friend of mine recently told me that he intended to limit himself to three more holidays by air in his lifetime. They would be to distant places which he couldn't reach by train. And he would savour every minute of his time in the Himalayas, New York City and admiring Table Mountain in Cape Town! Forty years ago, we never thought of recycling our rubbish, bottle-banks were unheard of and the campaign for lead-free petrol hadn't even begun. It is not inconceivable to think of rationing our air travel.
Thirdly, governments need to help us to go in this direction by removing the tax concessions from air travel and thus make it less tempting to fly to our school-friend's wedding in Copenhagen or her hen night in Dublin. If cigarettes were 20p a packet, giving up smoking would be a lot harder! Ryanair and Easyjet are equally addictive.....particularly when the price is so low.
Fourthly, the onus to change falls primarily on the rich world. Fewer than 5 percent of all the people on earth have travelled by plane in their lives. Even in Europe, it is the rich who fly the most. A recent report from the Civil Aviation Authority showed that, in the UK, people from social classes A and B, who make up 24 percent of the population, took 40 percent of all flights in 2003. Even at Stansted, where low-cost airlines account for nearly all the passenger flights, the average income of British passengers was more than £47,000. It's the rich world, and the rich within the rich world, who fly the most, whizzing to six or seven weekend breaks a year and second homes in the sun.
Carbon rationing within a system of contraction and convergence could be the way forward. This is the idea put forward by people like Aubrey Meyer and Mayer Hillman where an internationally agreed figure for a global reduction in emissions would form the basis of a system that required 'over-consumers' like the US to contract sharply, while 'under-consumers' like Bangladesh could continue to rise for a while until there was something approaching international convergence. It could allow a rapid, but orderly, retreat from fossil fuel dependency. Contraction and convergence could also take place at an individual level with people being given a 'carbon credit card'.
But it could be a long time before contraction and convergence is translated from an equitable theory into practical political reality. In the meantime, governments - particularly those in the rich world - need to act. They need to cut out the tax concessions, ensure aviation pays its full environmental and social costs, promote the railways and abandon plans for any new runways or airports. Only once government sets this new framework is it realistic to expect the majority of people to make different choices about taking a flight.