a fair point about the tiny amounts and the ozone layer comment is well made!
that is based on chemistry though, rather than physics ;-)

as for what my colleagues say, it's kind of half split between them giving me looks of horror, as if I had sprouted scaly wings and horns, and ambivalence.

I need to reiterate though that I don't disagree that climate change is happening. My quandry is with the magnitude of the effect that humans are having on it.
( Vipros. clever got me this far, then tricky got me in, Thu 19 Feb 2009, 16:56, 1 reply)

Okay, for physics rather than chemistry,
Ozone itself is at a concentration of about 2-8 parts per million (ppm) in the ozone layer. CO2 is about 380ppm in the troposphere. That small amount of ozone blocks almost all the UV energy from the sun. Trace gases, including CO2, have an effect. Fact.
(Stu Moo winner of five nobble piece prizes, Thu 19 Feb 2009, 17:51, closed)