LINDZEN'S ACTIVISM HAS earned him plaudits from conservative politicians like Senator James Inhofe, the Oklahoma Republican who has labeled global warming "the greatest hoax ever perpetrated on the American people." Inhofe has hailed Lindzen for presenting "a clear and coherent scientific counter to unfounded climate alarmism."

Lindzen's professional colleagues have been less kind, and there's no doubt that climate-change believers are aggressive proselytizers. But Lindzen insists that scientists cannot say precisely what the future holds, because they're just beginning to analyze some of the more complicated responses to climate change, such as how quickly ice sheets melt and to what extent this will raise sea levels. To him, these uncertainties are the heart of the matter, and they're why he feels justified about voicing dissent.

While the two sides differ on a number of questions, the debate really comes down to one thing: whether the warming we've begun to see poses a pressing problem or is something the world can adapt to over the long haul. According to Kalee Kreider, a spokeswoman for Al Gore, it is this question, more than any other, that embodies the difference between Lindzen and the former vice president.

"Where [Lindzen] disagrees is the issue of urgency," she says. "We just feel he's out of step with the mainstream scientific community."

To some extent, Lindzen has enjoyed success in getting his message out. The Washington Post/ABC/Stanford poll found that, while 70 percent of respondents want the U.S. government to do more to address climate change, 56 percent believe the academic community remains divided on the issue.

Meanwhile, book sales and TV ratings seem to indicate that global-warming skepticism is finding an audience. The Great Global Warming Swindle, a recent documentary featuring Lindzen and other skeptics, attracted 2.5 million viewers in Britain, prompting the Australian Broadcasting Corporation to buy the international rights so they could air it this summer.

The market is currently awash in books that, like Lomborg's Cool It, attack the majority view—including Crichton's novel, Christopher C. Horner's The Politically Incorrect Guide to Global Warming and Environmentalism, and Unstoppable Global Warming: Every 1,500 Years, by Dennis T. Avery and S. Fred Singer.

Chris Rapley, who directs the British Antarctic Survey, watches the success of what he calls "the professional confusers" with horror: After the documentary aired in Britain, the mother of one of his most talented ice-core analysts called her son to make sure he was certain climate change was really a problem. The film skewed key facts, Rapley said, but its real power lay in the fact that it appealed to people who don't want to think they're helping usher in an era of environmental disaster. "It's a message people wanted to hear," he says.

But while Lindzen and his allies are competitive in the marketplace of ideas, they're losing in America's cloakrooms and boardrooms. Democrats, who control Congress, aim to pass legislation in the coming months that will impose the same regulatory scheme that Lindzen opposes, a cap on CO2 emissions. And a host of traditional foes of such government-driven fixes, including the Big Three automakers and ConocoPhillips, now endorse it.

The 2008 election may determine whether Lindzen will continue to have a meaningful role in the public debate over climate change. If any of the Democratic candidates wins, Lindzen will be sidelined even further, since all of them are prepared to regulate emissions. The GOP field remains mostly in lockstep on the issue: John McCain backs mandatory cuts in greenhouse gases, but the remaining Republican candidates are much less enthusiastic about the prospect of such massive regulation.

Even more telling, though, is the attitude of businessmen, who increasingly see the wisdom of investing in CO2-mitigation strategies. Last winter in Miami, during a private meeting convened by an outfit called the Tudor Investment Corporation, more than a hundred portfolio managers gathered at the Mandarin Oriental Hotel to hear opposing speeches from Lindzen and Schneider on whether to factor global warming into investment decisions.

The two men separately made their case. Lindzen told the group that future warming wouldn't be dire. But when Schneider spoke, he appealed to the audience on blunt economic grounds. Catastrophic climate change, he argued, amounted to the kind of "low-probability, high-consequence risk" that investors usually seek to avoid. Tudor analysts could make their own decisions about whether he or Lindzen would end up being right, he added, and that decision would have huge financial consequences.

"I'm going to be right," Schneider added, drawing a laugh. "So then it's going to be a good thing you hedged."

After Lindzen and Schneider spoke during an afternoon session, Tudor's CEO, Paul Jones II, asked Schneider to come to his suite the next morning to chat about the company's future. "We had a long conversation on how they should invest," Schneider recalls. "It was not a matter of when, but how."

Lindzen left Miami without having done more than engage in cocktail chatter with Jones. He headed back to Newton and readied himself for the next PowerPoint presentation he had to deliver in a darkened room. But he wasn't bothered by the snub, since he believes he'll be vindicated eventually.

"My best guess is, 20 years from now it will be accepted that global warming is not an issue, and everybody will claim they knew it all along," he says, adding that he's not holding out hope of being recognized for his work by future generations. "Chances are, 20 years from now I'll be dead," he jokes, "and someone else will want to take credit."