Is there an active general 'green' online forum anywhere?

cashferret

This 'Green and Ethical Moneysaving' subforum is great but I'm looking for an online forum to discuss all sorts of green issues, from the practical side (energy saving, using less plastic, etc.) to campaigning, rather than just moneysaving-related things, and am struggling to find one - especially one that's busy.

Any suggestions? I'd have thought there'd be loads, or a least one big one.