21 September 2006
Our moral dissonance about flying reminds me of something a Buddhist once told me: "It doesn't matter what you do, as long as you do it with love." I am sure he knew as well as I do that our state of mind makes no difference to either exploited people or the environment. Thinking like ethical people makes not a damn of difference unless we also behave like ethical people. When it comes to flying, there seems to be no connection between intention and action.
This is partly because the people who are most concerned about the inhabitants of other countries are often those who have travelled widely. Much of the global justice movement consists of people - like me - whose politics were forged by their experiences abroad. While it is easy for us to pour scorn on the drivers of sports utility vehicles, whose politics generally differ from ours, it is rather harder to contemplate a world in which our own freedoms are curtailed, especially the freedoms that shaped us.
More painfully, in some cases our freedoms have become obligations. When you form relationships with people from other nations, you accumulate what I call "love miles": the distance you must travel to visit friends and partners and relatives on the other side of the planet. If your sister-in-law is getting married in Buenos Aires, it is both immoral to travel there, because of climate change, and immoral not to, because of the offence it causes. In that decision we find two valid moral codes in irreconcilable antagonism. Who could be surprised to discover that "ethical" people are in denial about the impacts of flying?
There are two reasons why flying dwarfs any other environmental impact a single person can exert. The first is the distance it permits us to cover. According to the Royal Commission on Environmental Pollution, the carbon emissions per passenger mile "for a fully loaded cruising airliner are comparable to a passenger car carrying three or four people". In other words, they are about half those, per person, of a car containing the average loading of 1.56 people. But while the mean distance travelled by car in the UK is 9,200 miles per year, in a plane we can beat that in one day. On a return flight from London to New York, every passenger produces roughly 1.2 tonnes of carbon dioxide: the very quantity we will each be entitled to emit in a year once the necessary cut in emissions has been made.
The second reason is that the climate impact of aeroplanes is not confined to the carbon they produce. They release several different kinds of gases and particles. Some of them cool the planet, others warm it. In the upper tropo-sphere, where most large planes fly, hot, wet air from the jet engine exhaust mixes with cold air. As the moisture condenses, it can form "contrails", which in turn appear to give rise to cirrus clouds - those high wispy formations of ice crystals sometimes known as "horsetails". While they reflect some of the sun's heat back into the space, they also trap heat in the atmosphere, especially at night; the heat trapping seems to be the stronger effect. The overall impact, according to the Intergovernmental Panel on Climate Change, is a warming effect 2.7 times that of the carbon dioxide alone.
Aviation has been growing faster than any other source of greenhouse gases. Between 1990 and 2004, the number of people using airports in the UK rose by 120%, and the energy the planes consumed increased by 79%. Their carbon dioxide emissions almost doubled in that period - from 20.1 to 39.5m tonnes, or 5.5% of all the emissions this country produces. Unless something is done to stop this growth, flying will soon overwhelm all the cuts we manage to make elsewhere. But the measures the government proposes are useless. The transport department suggests that the aviation industry should "pay the external costs its activities impose on society at large". This is an interesting proposal, but unfortunately the department does not explain how it could be arranged. Should a steward be sacrificed every time someone in Ethiopia dies of hunger? As Bangladesh goes under water, will the government demand the drowning of a commensurate number of airline executives? The idea is strangely attractive. But the only suggestion it makes is that aviation fuel might be taxed.
Unlike most environmentalists, who have also called for this measure, the government knows perfectly well that fuel tax cannot be imposed on international flights. It is prohibited under international law by article 24 of the 1944 Chicago Convention, which has been set in stone by 4,000 bilateral treaties - making it almost impossible to unpick. Now the government proposes that aviation be incorporated into the European Emissions Trading Scheme. If flights continue to grow, it will break the system.
The one certain means of preventing more flights is the one thing the British government refuses to do: limit the capacity of our airports. It employs the "predict and provide" approach that has proved so disastrous when applied to road transport: as you increase the provision of space in order to meet the predicted demand, the demand rises to fill it, ensuring that you need to create more space in order to accommodate your new projections. The House of Commons environmental audit committee calculates that the extra capacity the government proposes means "the equivalent of another Heathrow every five years".
The Department for Transport, along with the airline industry, claims that expanding airport capacity is "socially inclusive", in that it enables poorer people to fly. But a Mori poll commissioned by the Freedom to Fly Coalition, a lobby group founded by the aviation industry, found that 75% of those who use budget airlines are in social classes A, B and C. The people who are most vulnerable to climate change are the poorest inhabitants of the poorest nations, the great majority of whom will never board an aeroplane.
So what is to be done? There are two means by which the growth in flights could be reconciled to the need to cut carbon emissions. The first is a massive increase in the fuel efficiency of aircraft; the other is a new fuel.
As far as aircraft engines are concerned, major new efficiencies in the next 20 years or so are a pipedream. The Royal Commission reports that "the basic gas turbine design emerged in 1947. It has been the dominant form of aircraft engine for some 50 years and there is no serious suggestion that this will change in the foreseeable future." It is hard to see how it could be made much more efficient than it is already.
The choice of low carbon fuels for aeroplanes is similar to the choice of low carbon fuels for cars. According to a paper by researchers at Imperial College, London, it is technically possible to fly planes whose normal fuel (kerosene) is mixed with about 5% biodiesel. But biodiesel, as I have shown elsewhere, is likely to cause more global warming than it prevents.
Ethanol, the same paper suggests, would be useless: it is insufficiently dense and, in aeroplanes, extremely dangerous. This appears to leave only hydrogen. Jets could use hydrogen today, if instead of carrying passengers and freight they carried nothing but fuel - it contains four times less energy by volume than kerosene. But if this problem could be overcome, the researchers suggest, the total climate impacts of planes fuelled by the gas "would be much lower than from kerosene".
Unfortunately, when hydrogen burns, it creates water. A hydrogen plane will produce 2.6 times as much water vapour as a plane running on kerosene. This, they admit, would be a major problem if hydrogen planes flew as high as ordinary craft. But if the aircraft flew below 10,000 metres (33,000ft), where contrails are less likely to form, the impact would be negligible. What they have forgotten is that because hydrogen requires a far bigger fuel tank than kerosene, the structure (or "airframe") of the plane would need to be much larger. This means it would be subject to more drag. The Royal Commission points out that "the combination of larger drag and lower weight would require flight at higher altitudes" than planes fuelled by kerosene. In fact, hydrogen planes, if they are ever used, are most likely to be deployed as supersonic jets in the stratosphere. If so, their impact on the climate would be around 13 times that of a normal aircraft running on kerosene.
And that, I'm afraid, is that. As the Intergovernmental Panel on Climate Change discovered, "There would not appear to be any practical alternatives to kerosene-based fuels for commercial jet aircraft for the next several decades." There is, in other words, no technofix. The growth in aviation and the need to address climate change cannot be reconciled. In common with all other sectors, aviation's contribution to global warming must be reduced in the UK by some 87% if we are to avoid a 2C rise in global temperatures. Given that the likely possible efficiencies are small and tend to counteract each other, an 87% cut in emissions requires not only that growth stops, but that most of the aeroplanes flying today be grounded. I realise that this is not a popular message, but it is hard to see how a different conclusion could be extracted from the available evidence.
This means the end of distant foreign holidays, unless you are prepared to take a long time getting there. It means that business meetings must take place over the internet or by means of video conferences. It means that transcontinental journeys must be made by train or coach. It means that journeys around the world must be reserved for visiting the people you love, and that they will require both slow travel and the saving up of carbon rations. It means the end of shopping trips to New York, parties in Ibiza, second homes in Tuscany and, most painfully for me, political meetings in Porto Alegre - unless you believe that these activities are worth the sacrifice of the biosphere and the lives of the poor.
But I urge you to remember that these privations affect only a tiny proportion of the world's people. The reason they seem so harsh is that this tiny proportion almost certainly includes you.
· This is an edited extract from Heat, by George Monbiot, published by Allen Lane. To order a copy for £16.99 with free UK p&p (rrp £17.99), go to guardian.co.uk/bookshop or call 0870 836 0875. Monbiot has also launched a new website - turnuptheheat.org - exposing the false environmental claims made by corporations and celebrities.
http://environment.guardian.co.uk/climatechange/story/0,,1877388,00.html
