A counter-culture or a sub-culture, a person, well-meaning, and varied in degrees of dedication towards the theorized problems on Earth and the environment.
What most environmentalists have in common is a communal, casual concern through an individual to almost religious zeal, roughly based upon the 1960's industrial and cultural backlash. Such persons can be as moderate as a person who occasionally donates to an environmentalist fund and generally agrees with such notions, to extremists such as Greenpeace and the Earth Liberation Front, which have a history of interference and even endagerment of it's opponents. Many environmentalists are classified as being "liberal" or "democrat," in the United States, with a few fringe groups on the contrary to that generalization.
Worldwide, they currently have to battle politics, science, and opinion based upon cabinets and legislation, and private-sector funding which battles both sides of any given issue. Their biggest enemies are industry and economics from mining, fishing, ranching, farming, and oil production, right-wing politics and the so-called "science community." The lack of solid scientific proof on either side of any of their issues has perhaps not given overall credibility towards their plight, which largely makes people "environmentalist" in term only, or less likely to take up such a position. This has perhaps weakened their numbers, along with a generally non-results oriented way of politicking, where proof of their success is hard to determine.
Their success is largely in such groups as the World Wildlife Fund, which is one of the largest wild animal protective agencies, creation of the government's Environmental Protection Agency (the EPA), and recently, Earth Share, a centralized organization which places emphasis on organizing major environmental causes and groups.
Regardless the opinion of environmentalists, or their naysayers, their future will largely be based upon political trend, societal awareness, science favor, and long-term earthly consequences. Any factor could enhance or eliminate such belief and belonging to this group.
Recently, some environmentalists have recognized that they do not appeal to rank and file citizens of the USA. This is good news.
Compare an environmentalist with a conservationist, a person who wants to protect natural resources without trampling on everyone else's property rights. Typical conservationists are hunters, fishermen, campers, and hikers.
Gandhi was an environmentalist as well as peace-activist.
Much like a schizophrenic, environmentalists defend their beliefs by citing paranoid ideation and theory with no basis in reality.
Environmentalists have banded together, using theatrics, literature, and pop culture to manipulate, guilt, and decieve the unsuspecting into setting aside perfectly good lifestyles, products, and manufacturing processes for inefficient, overly costly, and counterproductive ways in the name of being "green".
It should be noted that the use of "me too" advertising, elitism, and pop culture depiction of green as "hip" and "cool" has met with varying success toward those with limited mental fortitude, although igniting a backlash amongst the more intellecturally capable.
2.) A social status seeker (see: conformist) with little technical grasp of the underlying concepts, attempting to jump on the green bandwagon in a misguided attempt to become "hip" or "cool".
So blinded by her self righteous status seeking crusade was she, that as Jane looked down her nose at the beat up 80's CRX passing by, she failed to realize that not only did it return 10 more MPG on two decade old technology, but was paid for and already returning savings to its owner. It also did none of the environmental damage that Janes Prius did, having already been manufactured some 20 years ago.