To fly or not to fly? New Internationalist March 2

this debate is a little bit silly. most figures have train at a quarter to a third as bad as flying. and sleepers are usually not four times as spacious as a normal carriage. luxury compartments might be potentially worse than flying economy but we are looking at averages aren't we? that's my ten cents anyway

i heard that more airlines are now switching to 'business class only' flights. presumably these planes, kitted out with larger seats and/or sleepers, will be even worse for the atmosphere (quite apart from their questionable social considerations).

i really appreciated kara's comments which show clearly that we ought to look at energy costs in a more holistic way, taking in a wide range of considerations. difficult, but more realistic.

Chris and Jeremy, Thanks very much for those comments. It is depressing!

And then I think, well if the train is going anyway and we don't take our efficient car, with two of us, across Europe, then we're saving the car emissions at least. And while we're sleeping in the compartment, we're not using a hotel which will also have a carbon footprint. We must leave a footprint somehow. It is just too complicated. But I am delighted that the debate is now taking place. For so many years, the environmental impact of everything was overlooked in its real cost. That must be a good thing and perhaps our grandchildren will not find it so complicated to measure their impacts.

Hi Kara

I wrote the article mentioned above in New Internationalist (access it at www.newint.org). My source for the aside about sleeper compartmentswas Fred Halliday in New Scientist (17 November 2007). He wrote: 'Trains are quite variable. In the UK, the average emissions are 40 grams per passenger-kilometre (g/p-km) but, depending on the engine, the source of power and the journey, the figure varies from more than 70g/p-km donw to 27 g/p-km. So going by train is usually better [than by car], but a small, fuel-efficient car with four passengers may be more carbon-efficient than taking one of the less efficient trains. Be warned, too, that taking a sleeper train from, say, London to Edinburgh or Paris to Venice may not always be greener than flying. Sleeper cars carry fewer passengers than regular carriages, and that could push the carbon footprint of the typical sleeper passenger above that of someone flying the same route at a typical CO2 emission rate for short-haul flights of 150 g/p-km.' Depressing, isn't it!

Hi Kara

I think the answer lies in the amount of space that you might use in a sleeper compartment, relative the the amount of space that you might use just if you were sitting upright. You might be using more (and substantially more) space in a compatment as compared to just travelling on a single seat, and this would mean tht the journey was less fuel efficient, on the basis of energy used divided by the (fewer) number of passengers. If you had a small bathroom attached to your compartment that would obviously make a difference as well.

Mind you, I have travelled in many sleeper compartments across Spain and northern Africa with three beds tacked either side of the compartment. It can be cramped but I'm sure that it's pretty efficient as well. Of course if you are more productive at your destination as a result of travelling in style this might change things ....but it's also notoriously difficult to measure too.

Jeremy