En-Club
Personally with local organisations like this I think it is either important to include the local area's name in the club, this allows locals to identify with the group (and also straight away are aware that it is a local club that is interested with their community).
I would go along with a name such as TOWN Sustainable Community (or TOWN Community Environmental Group).
A couple of warnings. The term "Green" unfortunately has negative conotations with many people, therefore may stigmise your group and drive people away from you (especially if you live in quite conservative area).
If you use a generic name, or something that doesn't suit your objective then it would gain support. Hence why I would recommend including your local name and the word community (both imply that the group only works because of "them" ... that is the local community, gives them a sense of ownership).
Earth Crew
Earthians
Earth lovers
Green Crew
Green Earth Crew
Greenies
The green team
(Town) Leaders for Environmental Awareness and Protection (LEAP)
My friends and I are starting an environmental club to go around town doing different projects and make people aware of some things they can do. What should we name ourselves?
