IN addition to their disappointment with the elections, major environmental groups are learning the pain of limits to growth.

From 1990 to 1993, membership fell 33 percent for Greenpeace and 35 percent for the Wilderness Society. The Sierra Club has lost 130,000 members and has accumulated deficits of nearly $3 million. Although groups such as the Natural Resources Defense Council (NRDC), the folks who brought us the Alar hoax, have held even, overall memberships peaked in 1990 and have been falling ever since. Only the Environmental Defense Fund, a group that values entrepreneurship and stresses incentives, has gained a substantial number of members.

What explains these dramatic losses? Why are people electing to invest less time and money in the traditional green groups? As with most interesting economic changes, several forces are at work.

First, with Clinton in the White House, Gore at the Naval Observatory, Babbitt in Interior, and ecologist Jack Ward Thomas as titular head of the Forest Service, some environmentalists believe that our environment is in good hands. They think they can relax their vigilance, secure in the belief that the people from the Potomac will manage our natural resources with prudence and sensitivity. With the environment covered by jolly green giants, concerned greens can direct their efforts to other causes.

Today's situation is similar to that faced when Jimmy Carter was in office. The "good guys" were in Washington and green groups' memberships and money declined. Some believe God sent Jim Watt, Ronald Reagan's Secretary of Interior, to save the environmental movement. Watt personified evil and exploitation, making it easy to recruit crusaders to battle him.

Second, the upper middle class and the wealthy provide most of the financial support for environmental groups. At the same time, Americans in the top 5 percent of the income distribution pay 43 percent of all personal income taxes. This is a terribly big hit. With government taking an ever bigger first bite, charities are bound to suffer. If the top 5 percent were paying 25 percent rather than 43 percent, contributions to all charities, the arts, churches, hospitals and schools, would increase dramatically. When government takes more there is simply less for worthy causes.

The third reason is by far the most complex. It involves culture and political evolution as well as economics. However, the short version is easily stated: Professional environmentalists have been found out.

For 25 years, the professional environmental groups have postured as selfless defenders of the public interest. The myth is that these underpaid servants of ecological integrity fight the public's battles against big business. Armed mainly with truth, virtue and purity, they fight the good fight though heavily outgunned. Clearly, all well-intentioned people would support such champions. But after a generation of success, the environmental organizations grew fat and rich. Their myth is losing its luster. Increasingly, people believe that under the costume of virtue lies sleaze and flab.

Jim Watt actually hurt the environmental groups because he cost them their purity. Before Watt, most of us who joined were active in the outdoors. Although there was overlap, Audubon was for bird watchers, Sierra Club was for climbers, the Wilderness Society was for backpackers, and so forth. We were lifestyle members; our environmentalism was integrated with our living.

Watt so offended those sensitive to environmental values that previously uninvolved people stampeded to the environmental movement. The organized groups became trapped by their gains. As David Foreman, a founder of Earth First! told me, Sierra stressed Club more than rocks and Wilderness emphasized Society more than trees. For most of the new members, environmentalism was a cause rather than a lifestyle, and today most causes have short lives. Stable members became ephemeral. Homelessness, world hunger, reproductive rights and other causes offered competing opportunities for well-intentioned people to demonstrate their good intentions by writing letters and sending checks.

With every good cause competing, the leaders of green groups emphasized marketing. They became salesmen, their product was their cause. A premium was placed on exaggerating or fabricating environmental crises to galvanize members and attract new recruits. But there's a tension between maintaining integrity and making the sale.

Incentives to make environmental problems big, dramatic and scary led to half-truths or outright lies about the actual risks of many alleged environmental crises. Alar, toxic waste, ivory, global warming, and other issues were often distorted by green groups as they tried to maintain their membership and budgets.

Time has exposed environmentalists as just another special interest. Every dollar spent on a cause defined in New York and D.C. offices is a dollar less for local problems people can see and feel. The obvious failures of legislation such as Superfund and the problems with the Endangered Species Act caution people to be skeptical of dire warnings from Manhattan and the Beltway.

Just as political corruption and deception have fueled a voter backlash, so deception by green groups has real consequences. A new environmentalism that recognizes the importance of property rights, entrepreneurship and incentives must emerge if we are to preserve environmental quality and ethical integrity.