I think the... the public is obsessed with the phrase 'global warming', which is not the problem. I mean global warming I think is a very misleading phrase, because there are other things which are much more important and easier to measure; for example, stratosphere cooling, and stratosphere cooling is much larger than global warming, because global warming is supposed to be a rise in the average ground temperature. The average ground temperature over the earth is impossible to measure since most of the earth is ocean and we don't have instruments. So this average ground temperature is a fiction. I mean, nobody knows what it is, there's no way you can measure it and it's not particularly important anyway. I mean, what's important is how much rain is going to fall next year, how many hurricanes there are going to be, and how much ozone there's going to be. Well the stratosphere cooling is something we really know a lot about because that's easy to calculate. It's a direct effect of carbon dioxide which cools the stratosphere just by radiation, it's independent of weather, and it's very large. So that's a measurable and known effect of carbon dioxide, which can be extremely serious because it immediately affects the ozone. As you cool the stratosphere you produce more ice crystals in the stratosphere and that has a very destructive effect on the ozone.