[magic9mushroom]

Ozone absorbs ultra-violet light, reducing the amount we measley organisms on the gound have to deal with. The real nasty stuff is deflected by the megnetosphere, which is what gives us dem pretty northern fairy lights. While UV rays do carry energy, the amount of heat transferred is relatively negligable. Most heat is carried on longer wavelengths, such as infra-red, which carry on unempeded through O3.

The two effects are commonly confused. Depletion of ozone means less UV is absorbed, causing sunburns and cancer. The chlorofluorocarbons that are responsible for ozone depletion are not greenhouse gasses.

Greenhouse gasses are a natural component of Earth's upper atmosphere. Most of the heat reflected off of the surface of the Earth escapes into space, but greenhous gasses reflect some of it back. Human activity is now known to be increasing the amount of greehouse gasses in the atmosphere, reflecting more heat back to earth, and causing global temperatures to rise.

That is the difference.

CFC's are actually very potent greenhouse gases, but the concentration is low enough that they don't really make a difference.