Apropos of our recent discussion on disposability (see here and here), the Guardian, in its green living column no less, trotted out that old tired question about whether a reusable ceramic cup is really better than disposable cups. They use that ancient statistic that says you have to use a thousand polystyrene cups before you equal the impact of manufacture of one ceramic cup.
This argument is dangerously misleading. It gives you the idea that, sitting in a coffee shop, faced with the choice between ceramic and polystyrene, you should choose the throwaway.
But what the studies never say is that if the ceramic cup already exists, if it is already sitting there ready to be used, then using even one polystyrene cup has more impact. If the reusable cup is sitting on the shelf, then then there is no impact of manufacture, but the polystyrene will have to be thrown away and replaced. Stick with reusable.
Another case where simple common sense trumps science (see more on this here).