Until you lumped in ozone, nothing to do with the greenhouse effect. Totally separate issue, and is certainly not affected by farts, bovine or otherwise.

Efros

If you are about the environment, tick the "offset carbon emissions" box for an extra £25! (or just about)

Heck, send me £20 and I will offset our carbon emissions by using large carbon absorbing sponges and planting lots of tomatoes in my garden!

Oh, and uhm, let's start offsetting volcano emissions, cow farts & politician's hot air.

"one of the first big airlines to really push for carbon trading (offsetting one’s carbon footprint with green initiatives)"

That'll be those initiatives where you pay a bunch of people to cut down some native vegetation in order to plant some kind of monoculture, or you pay them to pretend that they're planting trees, or someone in London just shuffles papers around on a desk and claims that the emissions (real) have been offset (in an imaginary world where the pixies rule).

Maybe Second Life will end up soaking up a bit of carbon dioxide once those emissions traders run out of other places to trade with. The pixies will rule after all.