We've known the physics for quite a long time. That is simple molecular spectroscopy, but you have to be careful to distinguish between tropospheric ozone, which is at the ground and is associated with smog, and stratospheric ozone, which is much higher up.
Ozone itself is a greenhouse gas. It can absorb radiation. If you have a reduction of ozone in the stratosphere because of the ozone-depleting chemicals, such as the CFCs reducing the amount of ozone in the stratosphere, then you're removing that potential warming. It's getting colder. The same way, if you have pretty small events on the ground, you are in fact adding more greenhouse gas at the surface and warming up the surface much more.
I hope, Andrew and Francis, I've done justice to that. They are more active scientists than I am.