I think I've finally decided to do Geography at uni

There's one thing that's stopping me from being !!! about it though; the jobs I can get with it afterwards. In all the other threads I've seen, people have gone on about careers in finance and accounting, business shizzle, management, working for the local council.... gawwwwd the thought of any of that makes me want to cry!
I'm more interested in the human side of geography, and I'd love to travel round the world and do something that would make a different to people's lives. I'm thinking of taking a year out (dunno when) and just doing charity work abroad - not for ucas or anything, but just for me.
I want to make a difference, a proper difference, and do something really worthwhile in the future. I don't know if that's a realistic aim, but you have to shoot for the stars...
So do you think a Geography degree can open up doors for those kind of things? I'm honestly clueless; opinions would be great!
Thank you in advance

EDIT: QUESTION: I've read a few 'degree guides' recently and they all tend to say 'The type of course chosen (BA or BSc) reflects the student's options at A-level' i.e. if you do sciences, then you'll do the BSc course and vice vesa.
But erm.. I'm doing Bio, Maths and Geog which, according to that means I should be doing the BSc but I want to do the BA. If I apply for the BA course, they won't reject me/put me in the BSc course anyway, will they?