How environmentally friendly is Public Transport?

Every time I drive to Norwich I pass a bus either travelling to or from the city. And it is invariably nearly empty. A big, double decker bus, with two or three passengers. How can this be environmentally sensible?

There is a sort of mantra that goes along the lines "buses and trains good for the environment, cars and aeroplanes bad. Private transport bad, public transport good." But hang on, aeroplanes are public transort, every bit as much as buses. And on all the flights I have been on recently, there have not been many empty seats.

I also read somewhere (I have forgotten where) that some modern trains are now so heavy, and carry relatively fewer passengers, that they are less energy efficient than a private car with four passengers.

While I am sure that public transport makes sense in urban areas, I am equally certain that it is not environmentally friendly in rural areas. Huge empty buses lumbering around tiny country lanes, do not make sense, and are only viable because of the subsidies given by local councils.

Another fact that the green movement is ignoring when constantly pressing for more and better public transport, is that this simply encourages people to make more and more uneccessary journeys. Cheap efficient public transport makes it possible for people to live further and further from their place of work. And it makes it possible to travel more frequently. Airlines such as Easy Jet and Ryan Air demonstrate this very clearly and simply. Their flights are nearly always full, because they are so cheap -- or you caould express that the other way round. But the net result is that people now travel more frequently, and further afield. There is no difference in the economics of this phenomenon, between airlines and trains, it's just that we are more readily concious of the effects it has had in the airline industry.

Like so many aspects of the energy debate we are actually ignoring many of the fundamental realities. Perhaps the most fundamental of them all is that while energy is cheap, we will continue to use is. Cheap air travel is possible, because the tax on aviation fuel is less than that on car fuel. But beyond that, the other fundamental reality is that we, in the UK are, relative to most of the world, wealthy. We have large disposable incomes, that are not needed for survival. Food is cheap, and once we have paid for the bare essentials in life, we still have, on average a lot left over. Shopping has become a leisure pursuit, an end in itself (sad, but true). And virtually everything we spend our money on has energy implications. And while the world's population continues to soar, there is no possibility of energy consumption falling. And no possibility of controlling greenhouse gas emissions. That is why preserving natural habitats is SO important. Every acre we save is one less contribution to global warming, but it is also one more step to preserving something for the future. One day the world's human population will crash. It's not if, it's when (to quote health experts discussing bird 'flu'). It may not be in my life time, but it will crash. I want to see as much of the natural world left behind for the time after that crash.