Space, the final...solution?

I'd already posted on this baby, but in reviewing the posts (a lot, but some good ones, so I broke my 'no more than 100' rule) I found I might have been hasty in my critique of our reaching for the stars efforts. Well, at least the punting rich geezers up there bit , anyway.

As there are some here who seem to know, I would like to tap into the collective intellectual resource being brought to bear to help me with a question.

For a while I have been perhaps a tad less than fair to one Mr. R Branson in having doubts on his claimed green campaigns - towing planes to take-off (did that ever happen?), biofuel-powered planes (could that ever happen?) and £25M eco-prizes (does that include waiving the rights to profit sharing?) - especially when one of his highest profile current extravaganzas seems to be sending rich tourists into space atop what I had thought to be a massive column of greenhouse gasses.

Now it seems that I may have been unjust, and it's all 'just' (I have to presume there's a smidge of energy in the production, and possibly a tad of pollution still involved in the combustion) oxygen and hydrogen, though I also do recall steam to be considered a greenhouse gas.

We have a most helpful earlier offering as regards Ariane, but can anyone enlighten me as to what other space borne efforts, including Virgin Galactic, actually do consume and exhaust?

ADDENDUM:

One of the (many) frustrations of a moderated system is that Qs can cross with As, and debates can get a tad jumbled. A classic of the former has just happened here, and I pretty much got my answer in an overlap. Fortunately, it seems my usual admittance of bozoness, combined with a quest for answers, was not far off the right track. Unless this latest guy is wrong, I guess. He doesn't sound like he would be, though.