Freethought

Green (see Australian Greens).
Freethought (see Wikipedia).

There isn't really a specifically Green way to be a freethinker but as these are the two labels that together best sum up my way of looking at the world I jammed them together on the assumption that no one else would have done so previously and it seems to have worked. Actually I am not completely happy with the title but it is difficult to label yourself if you're a freethinker. Anyway, it will do for now.