The reason nomenclature like "Green Libertarian Socialism" is invented is because Communism has been so thoroughly trashed by the propaganda machine in the FSoA over the last century. So the lefty crowd looks for new buzzwords to identify the ideas that hopefully are more palatable to J6P.
A Rose by any other name... 
RE
No, it's not just buzzwords. Socialism is governmental control of the means of production. Communism is (quoting Wikipedia) "the social, political, and economic ideology and movement whose ultimate goal is the establishment of the communist society, which is a socioeconomic order structured upon the common ownership of the means of production and the absence of social classes, money, and the state." The theoretical basis for the Communist parties that ran the USSR, China, etc., was that by establishing socialism, a communist society would eventually emerge. That is why the second S is USSR is "Socialist" and not "Communist".
Now I think we can agree that the communist socioeconomic order described would be a wonderful thing, but I for one do not think its emergence is inevitable. In fact, I can't imagine it happening at all short of a global cure of Original Sin (to put it in Christian terms -- think "Maya" for those of other religious persuasions), and while I personally think that will happen someday, it won't happen through political means. You can't force people to be good. All you can do is remove the survival problem, and let them think for themselves. So as I see it, to call yourself a communist is to promise more than you can deliver.
Hence I am not a Communist, because I am leaving that assumption of the emergence of a communist society out of the picture. I would like it to happen, but that's just personal, not a political goal. But that "let them think for themselves" is the reason to include the modifier "libertarian". While I am very religious, I would not want to exclude atheists from the political process, as long as they are ok with religious people being included. In fact, I would prefer that both religous and non-religious be in charge. Let Darwinism and Intelligent Design be both taught as "this is what some people think, and why they think that, and that is what other people think, and why" The only exception is, of course, that any religious group that attempts to force conversion must be suppressed, as being violators of the freedom of others.
As for greenery, well, that's just CFS as far as economic means and goals are concerned in a world of declining resources and climate change. It is really more intended to modify 'libertarian' than 'socialism', in that it emphasizes that one's personal freedom does not extend to doing things that harm the biosphere.