LET THE BIRD watchers beware. Let the pointy-headed backpackers seek refuge in down-lined foxholes. This new year of 1981 promises to deliver us from a decade of folly, that era of indulgent nonsense known perjoratively as "environmental extremism."

This anyway, is what I keep reading in the ban - from positions of power. Reason and prosperity restored. Let the good times roll.

I am exaggerating, but only to convey the flavor of the season. The president-elect himself talks about "extremists." His designated budget director suggests an omnibus "suspense bill" that would postpone, rescind or repeal hundreds of new federal regulations. The man set to become interior secretary is a certified sagebrush rebel who wants the federal government to cease and desist its scolding management of federal lands. In the transition gossip, a leading anti-regulation propagandist, economist Murray Weidenbaum, is mentioned as a possible chairman of the Council of Economic Advisors.

The trouble is that, whatever these folks may say or do with laws or regulations, they really are not going to be able to halt the environmental movement.

No doubt they will say and do a lot. Indeed, I think we are approaching a clarifying interlude of political collision and debate on the environmental issue. What exactly do Americans want? Clean air or jobs? Whose values should be served? The wine-and-cheese liberals with their wilderness fantasies or the blue-collar workers who depend on belching smokestacks for their livelihood?

Roughly speaking, that is how the anti-regulation conservatives have posed the debate and, in those terms, the questions seem easily resolved. Go with growth. The birdwatchers can eat feathers.

Like all great political delusions, the conservative vision of environmental extremism has just enough truth to it to evoke popular sympathies.

There is a flavor of class bias surrounding certain environmental issues, protecting pristine shores and woodlands for the precious few who can afford them. There is regulatory confusion and scientific controversy and, yes, old-fashioned nonsense. All that needs attention.

The delusion, however, stems from the satisfying conviction that the environmental issues are really only a class conflict, an argument between the effete tastes of the Sierra Club and the bread-and-butter demands of steel workers. That makes good hot-blooded rhetoric before the right audiences and will doubtless lead to short-term victories for the steel industry and paper mills, for auto makers and coal companies and other business interests that feel oppressed, even overwhelmed, by the regulatory requirements enacted in the Seventies.

In the long run, if they pursue the matter as zealously as their rhetoric suggests, conservatives may find that the class argument puts them on the wrong side of the future, both politically and philosophically.

To explain the delusion, let's put aside the well-known environmentalists, the wilderness bleeding hearts, and consider some other environmentalists who do not usually get much fanfare. I am thinking, for instance, of Boeing, Exxon, Dow Chemical, Minnesota Mining, Caterpillar Tractor, Shell, British Petroleum, Krupp and Phillips, to name a few.

All of these large corporations have added divisions in recent years to sell environmentalist values -- which will help other enterprises comply with the new environmental codes, from filtering smokestacks to altering chemical wastes. This is no longer a minor enterprise of world commerce; the environmental business in the United States approaches $50 billion a year and has grown at about 20 percent annually.

Still, no one can reasonably expect those corporations and others to lead the counterattack this year when the Clean Air Act is up for renewal and critics of "environmental extremism" try to gut the landmark legislation. Nor will they scream too loudly when the Reagan administration defers and rescinds the regulatory deadlines.

But there is another group of "environmentalists" who ought to be considered in the coming debate -- the corporations which discovered that complying with federal standards on pollution produced a startling result for them. It increased their profits.

On the question of profits, let me cite an unimpeachable source -- the Harvard Business Review. The HBR, as its regular readers call it, is not exactly a wimpish tool of the ecofreaks; it addresses an audience of corporate managers on an endless array of business questions, led by the most important question of all: What is the bottom line?

The bottom line, according to an article by Michael G. Royston in the November-December issue, is: "Making Pollution Prevention Pay." The professor cites rather generous examples of real-life companies which increased their profits by doing good things for the environment.To mention a few:

Dow Corning found that recovering chlorine and hydrogen which used to vanish into the atmosphere in its silicon process can reduce operating costs by $900,000 a year. A capital investment of $2.7 million in recovery equipment would thus produce an annual return of 33 percent. Not bad.

The 3M Company, while it was substantially expanding production over the last five years, reduced its annual pollution dramatically. The clean-up saves many millions."By viewing pollution as an indicator of waste and an opportunity for profit rather than as a costly threat," Royston writes, "the company had, by 1979, saved over $20 million."

Hercules Powder spent $750,000 to reduce the solid wastes it was putting into the Mississippi River; it now saves $250,000 a year in lost material and water costs.

A Goldkist poultry plant cut water use by 32 percent and reduced wastes by 66 percent. The cleaned-up process saved $2.33 for every $1 expended.

The chairman of Hanes Dye and Finishing Company testified: "Cleaning up our stacks and neutralizing our liquids was expensive, but in the balance we have actually made money on our pollution control effort, EPA has helped our bottom line."

These are small and perhaps narrow examples of a large and fundamental point. The era of environmental regulation, notwithstanding its confusion and occasional absurdities, is really rooted in capitalistic self-interest. A few corporations already understand this -- precious few, I fear -- but as the world moves further into the Eighties the message will become more obvious. The environmental ethic, as energy prices continue to rise and global contests over resources become the regular order, will force itself upon the private agendas of private interests.

To some extent, this is already happening, especially in Europe where industrial processes are being adapted imaginatively to the new realities. Royston cites, for instance, the German steel industry, which "has recycled 99 percent of the water it uses and converted over 90 percent of its solid wastes into other useful materials. It is in Germany where coke ovens are being moved to enclosed quenching zones to recover gas and steam as energy sources and to eliminate air pollution, where the aluminum industry is using a closed fluoride cycle and where the rubber and plastics industries have a large number of schemes to recover, resynthesize and reuse waste materials as fuels by a variety of specialized . . . techniques."

In philosophical terms, the environmental movement has been led by the spiritual banner -- the moral argument which appeals to liberals. It is wrong for one man's smokestack to foul the air that others breathe, for a coal company to destroy a river in order to increase its profits, or whatever other example one wants to choose. This is called "externalizing" the costs of production. A strip mine operation which fails to reclaim the land is pushing the cost of reclamation off on someone else, the future generation or the public treasury, in order to maximize its profits.

That's the do-gooder rationale for environmental protection, which is morally sound but politically vulnerable. Saving birds is not the business of America; the business of America is business.

In the coming generation the economic rationale will become at least as potent in forcing change on American society. In the long run, the environmental ethic is the key to insuring the robust economic growth which those blue-collar industrial workers and the rest of us want. That is another way of predicting that conservation, that unexciting concept for saving oil, will prove to be the most efficient solution. The good life depends upon it.

As a nation, we are only at the beginning of fundamental changes in our values. If you doubt that, consider what's happened to automobiles in the last decade. If you think this is not a national concern in which the federal government must exercise power, consider what the auto industry has done on its own to prepare for the future. Washington has had to force efficiency on a kicking and screaming Detroit -- just as the environmental movement has done to other industries.

Efficiency, of course, is the dominant new value of the marketplace -- making the most of everything we have, capturing and using what used to be considered "waste," quality pushing aside the old standard of planned obsolescence, high-efficiency design replacing the old standard of gross size.

That doesn't sound extremist. Nor liberal, for that matter. In philosophical terms, one can argue that environmentalism is really a cause made for conservatives, if they could only see the future more clearly.