The greens are feeling rather blue these days. Sept. 11 depreciated the claim that the ruin of the environment is the single most urgent threat facing civilization, and it deprived them of their favorite whipping boy--the Bush administration.

A few days after Sept. 11, the Sierra Club posted a remarkable announcement on its Web site declaring that the club had “removed any material from the Web that people could perceive as anti-Bush” and “are going to stop aggressively pushing our agenda and will cease bashing President Bush.”

Even Greenpeace, the bad boy of the environmental movement, backed off its Bush-bashing. Because President Bush is off-limits for the time being, environmentalists are directing their invective instead toward Bjorn Lomborg, a hitherto unknown Danish statistician who burst on the scene last fall with a blockbuster book titled The Skeptical Environmentalist: Measuring the True State of the Planet (Cambridge University Press). Lomborg’s story has captured the media’s attention because he describes himself as an “old left-wing Greenpeace member” who changed his mind about the environmental prospects for Earth.

Far from being on the precipice of ruin, most--though not all--environmental trends are getting better in the industrialized world, and should also begin to improve in the developing world in the coming decades.

Lomborg’s optimism challenges the pervasive gloom of environmentalists, which he describes as “The Litany”: We are running out of resources; pollution and global warming are increasing; species are dying off at massive rates; and prospects for the planet are grim.

Environmentalists have reacted with the kind of fury the medieval church reserved for heretics, setting up anti-Lomborg Web sites and raising a ruckus in the media.

Their counterargument is twofold. First, it is argued that Lomborg either has his facts wrong, or misinterprets the facts. In a book of Lomborg’s large scope it is inevitable that there will be some arguable conclusions or omissions, and many of these criticisms have validity. But far from a calm argument, some prominent environmentalists describe Lomborg’s book as a “scam,” and go as far as to say the book should not have been published.

But the second argument against Lomborg is amusingly ironic, and exposes the fissures among environmentalists. Lomborg’s Litany, they say, is a caricature of what environmentalists really think.

“I absolutely agree that the end of the world is not nigh,” said David Sandalow of the World Wildlife Fund in a recent forum with Lomborg in Washington, “and I absolutely agree that many trends are getting better in the world.”

Alan Hammond of the World Resources Institute added that Lomborg’s Litany is attacking a “straw man.” Hammond said the Litany “does not reflect what most major environmental organizations are concerned with today,” while Sandalow said that Lomborg’s Litany “ignores all the good news about the environment regularly put out by environmental groups.”

This is disingenuous. If environmentalists have suddenly become optimistic, then why the ferocious attacks on Lomborg? Moreover, if environmentalists have supposedly abandoned gloom and doom, then they have some explaining to do and mea culpas to offer.

Polls repeatedly show that large majorities of Americans think environmental quality in the United States is getting worse. The most startling is perhaps a Roper poll in 1998 that found that 57 percent of Americans agree with the statement that “the next 10 years will be the last decade when humans will have a chance to save the Earth from environmental catastrophe.”

Why would the public think this if environmentalists have abandoned a gloom and doom view of 30 years ago and are now putting out good news? Environmentalists say, incredibly, that it is the media that are misleading the public. Well, at last environmentalists and their critics can agree on something.

The deeper answer is that the noisiest advocacy groups such as the Sierra Club, Greenpeace, and the Worldwatch Institute haven’t abandoned their gloom-and-doom views. But if serious environmentalists have a more balanced view about basic trends and the world’s prospects, they have a duty to deprecate the frothy activists and correct media misperceptions.

The World Resources Institute’s Alan Hammond may have started doing so in a small way. Hammond dismissed one of the leading figures of modern environmentalism, who is one of Lomborg’s main targets--the Worldwatch Institute’s Lester Brown. Hammond said that “I would not regard (Brown) in fact as a significant figure in advancing environmental concerns.”

This is akin to a conservative saying that Milton Friedman isn’t a significant figure within free-market ideology. Yet it is a healthy first indication that serious environmentalists are beginning to mature, to recognize and celebrate human creativity in solving real problems, and that it is not necessary to scare the daylights out of the public to achieve progress.

Steven F. Hayward is the F. K. Weyerhaeuser Fellow at AEI.