"Environmentalist" - short definition.
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.
Such popular ideals of current environmentalism is endangered animal recognition, global warming, deforestation and ozone layer depletion. There is a small U.S. political party dedicated to generalized environmentalist organization, the "Green Party," known as "Greens" and "Greenies," headed by Ralph Nader. While the party is growing in strength, it's standpoint has much more been attributed towards "swinging" the vote either for or against the other two major American political parties, Republicans (conservative) and Democrats (liberal), et al.
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.