The environmental movement, nurtured by Earth Day's youthful enthusiasm, has matured into a political lobby of formidable sophistication.

The change has taken place quietly, through a decade of energy shortages, unemployment, recession and inflation.

While the obituary of the movement has been written and rewritten, the record shows that the dozens of groups that lobby for environmental causes are stronger, better organized and better funded than ever before. Polls show increasing support for environmental issues, even at the height of the Proposition 13 tax-cutting movement.

If there were any doubt as to clout on Capitol Hill, it was dispelled a few weeks ago with the House of Representatives' vote on the Alaska lands bill.

The vote was to have been very close. After all, the oil, timber and mining companies, the National Rifle Association, the Chamber of Commerce and the AFL-CIO - anyone who is anybody - were lined up against the environmental groups.

But the conservationist-backed bill, sponsored by Reps. Morris K. Udall (D-Ariz.) and John B. Anderson (R-Ill.), won by a landslide vote of 268 to 157 over the rival measure of Reps. John D. Dingell (D-Mich.) and John B. Breaux (D-La.).

The environmental lobby, said Udall with a touch of wonder, is "head and shoulders above anything put together in the public interest field since the civil rights movement."

Breaux lamented, "They're very effective. I've got to compliment anybody who kicks the hell out of me." Lloyd Meeds, a former congression who lobbied toe-to-toe against the conservationists on the Alaska bill, observed, "The environment lobby is the second most effective grass-roots lobby, next to Common Cause. I'm envious."

The environmental influence on the Hill is matched by unprecedented access to the executive branch. While conservation groups constantly complain that the Carter administration is not living up to its promises, they boast privately that many top environmental lobbyists have been appointed to high positions.

Furthermore, leaders of the top dozen groups meet personally with the president every six months. Carter also invited them to submit a one-page memo to him every two months, a memo that can't be altered by White House staff.

However, while the environmentalists' Alaska Coalition is remarkable in its scope, intensity and political sophistication, it is open to question whether an equal effort could be mounted on other key environmental issues - hazardous waste disposal, for instance. Alaska has a romance that toxic chemicals don't seem to evoke.

"The heart of the environmental movement is in the wilderness," said Richard Ayres, a Natural Resources Defense Council attorney who labors in the often-dry field of environmental regulation. "It's harder to organize people around public health issues. Drinking water and clean air don't seem to grab the public's imagination."

Almost 40 organizations form the Alaska Coalition: the groups that worry about pollution, the groups that defend whales and whooping cranes, the groups that lobby for wide-open spaces. More than a dozen environmental groups now have Washington offices that rival the best corporate lobbies.

If there were ever blue-jeaned ecofreaks working for the Sierra Club, they're invisible now. Highly trained attorneys, graduates of the top law schools in the country, represent the Natural Resources Defense Council and the Environmental Defense Fund.

Many of the environmentalists, such as Charles Clusen of the Wilderness Society, have been lobbying Congress for almost a decade. Silverhaired Thomas Kimball, Washington representative of the National Wildlife Federation for 19 years, earns $80,000 a year, and National Audubon Society executives are equally well-paid.

"This isn't the children's crusade anymore," remarked one House aide. "The opposition had Gov. Jay S. Hammond [of Alaska]. We had Gov. Russell Peterson," a former Delaware governor who heads Audubon.

The environmentalists also had President Carter, Interior Secretary Cecil D. Andrus, Jacques Cousteau, Henry Cabot Lodge, Cathy Douglas, Laurance Rockefeller, Adm. Elmo Zumwalt, Theodore Roosevelt IV and former army secretary Elvis Stahr.

Altogether, the Alaska coalition has spent about $200,000 in a year and a half. "Peanuts," it says, compared to the state of Alaska's $2 million lobbying fund and the industry-backed Citizens For Alaska Lands' war chest of over $1 million.

But the environmentalists' organization overwhelmed the opposition:

More than 50 environmental lobbyists fanned out to Hill offices over a month before the bill came to the floor. Each took charge of several undecided members of Congress and reported back regularly to a day-by-day head-counting operation.

More than 3 million names on the computerized mailing lists of different groups were assembled by congressional district. "I'd say, 'So-and-so's wavering,'" Udall recalled. "They could push a button and have 800 Mailgrams in to the guy the next day."

In each congressional district, an Alaska committee was formed with about 10 community leaders and key supporters of the members of Congress. During the Easter recess, more than half of the House members were personally visited by these influential Alaska advocates. Followup calls came three weeks later.

A media campaign was timed to include full-page ads in Washington newspapers before the vote, hometown newspaper editorials and strategic leaks to harm the opposition. For example, a U.S. Borax company letter suggesting that job applicants lobby against the conservationist's bill somehow found its way into environmentalists' hands and from there to the press.

One factor that has made it easier for environmental groups to build strength in recent years is the 1976 Tax Reform Act, which permitted certain nonprofit groups to expand their lobbying. "Without [the new act] we would have had to take a lower profile," said Joel Thomas, a National Wildlife Federation attorney.

However, no matter how successful they are becoming, environmentalists continue to see themselves as underdogs. "Industry outspends us 100 to one," Thomas said. "We're saving a little here and a little there, but you've got to like losing games to be in this business."

For every Alaska vote, he said, there are defeats on other issues. In spite of an active water projects coalition, for instance, "almost none of the boondoggles have been stopped.It's business as usual." Thomas said. And as for Alaska, so many compromises were made with oil and mining companies in the Udall bill that "what came out was highly favorable to industry. They got 95 percent of what they wanted. We stopped them from getting 100 percent," he said.