Nothing shows more clearly the political difficulty of dealing with climate change than aviation.
In developed countries, flying is immensely popular: the number of people jetting in and out of Britain every year is more than three times the national population, and the figure is rising steeply. Flying has annihilated distance, shrunk the world; it has facilitated the global business deal and the easily taken sunshine holiday. More, since the arrival of the cheap flight, it has made Shangri-La available to everyone, not just the well-off.
But flying, with its soaring popularity, is now the fastest-rising contributor to the emissions of the greenhouse gases, principally carbon dioxide, but also oxides of nitrogen and water vapour, which are causing the atmosphere to warm, with potentially catastrophic results for the world. The Tyndall Centre for Climate Change Research calculated last year that if Britain was to meet its target of cutting greenhouse gases by 60 per cent by 2050, and aviation emissions were not reduced, all other emissions - from households, businesses, energy generation and motor transport - would have to go to zero. Flying would be taking up everything that was available.
The message has been hammered home from various eminent quarters in the past five years. The Royal Commission on Environmental Pollution said in 2002 that if climate change was to be countered, not another airport runway should be built in Britain. The House of Commons Environmental Audit Committee said in 2004 that air travel would make the Government's climate targets "meaningless and unachievable".
In June this year, in a letter to The Independent, an unprecedented coalition of senior greens, scientists and politicians demanded aviation emissions cuts - or society would have to pay an unacceptable price.
Yet aviation emissions are not on course to shrink. Quite the opposite. The Aviation White Paper of November 2003, which is still government policy, foresees aircraft passenger numbers rising from 180 million per year to 476 million per year by 2030, and five major new airport runways being built to accommodate the increased demand - the approach known as "predict and provide".
And this was published in the same year as the Energy Review, which first made stabilising the climate the prime aim of British energy policy, and set in stone the 60 per cent 2050 reduction target. Any unbiased observer would simply say: this is crazy. The Government is facing two ways at once. How can these positions be reconciled?
The answer is that they cannot, and sooner or later a bold prime minister will have to come to grips with the contradiction.
Michael McCarthy is the Independent's Environment EditorReuse content