Are big planes damaging the ozone layer?

Chris - We've got to bear in mind that big planes are going to pump out a lot of CO2 and CO2 will increase global temperatures and at high temperatures, I think, the equilibrium has shifted in favour of making less ozone and degrading more ozone. So you would have less ozone.

Dave - And I think, if the plane is flying through the stratosphere, as concord was, then just pumping water in there can form little ice crystals which are very bad for ozone, but lower down, I don't think that's a big effect.

Chris - So the height is important thing.

Dave - I think that's certainly a very, very important thing.

Chris - But presumably quite small in comparison with CFCs, chlorofluorocarbons, the things we used to put in fridges, which are known to be terrible for ozone.

Dave - Yes and I think essentially there aren't many planes up in the stratosphere flying around, especially now, since concord has given up the ghost.