Of course we need to work through the democratic process, but there is more to individual action and single-issue pressure groups than you imply. You talk of changes being “made by green lobbies working within parties in govenment,” but government won’t make these changes unless it is convinced that they are palatable to a fair proportion of the electorate.
For example, we may want to persuade governments to increase aviation fuel duty. We campaign within a party which has “a core ideology, a track record on the environment and most importantly a chance of power” (by the way, did you have one in mind?) Senior policy makers within the party worry that there is no public stomach for such a change. They know that people are liable to tell opinion pollsters they’re in favour of something that will cost them more, but while wimping out in the polling booth. Surely it would be helpful to be able to point to a large number of people prepared to increase the cost of their own air travel by using an air travel emissions offset scheme like this one.
I am fully aware that such schemes are highly controversial, but I am trying to argue that individual action (often spurred on by single-issue groups) can serve to catalyse the formal political process, even when its direct impact is negligible, by demonstrating that the change is truly acceptable to the public.
I’ve got more to say on this one, but it’ll have to wait.