LINDZEN DOESN'T MIND getting bashed—the criticism bolsters his sense that he's fighting for the truth. "I feel that my field is being raped, and someone should do something about it," he says.

John M. Wallace, an atmospheric scientist at the University of Washington who has known Lindzen since their grad-school days in Cambridge, Massachusetts, says Lindzen's challenge to climate-change orthodoxy is driven, in large part, by his inner resistance to backing down. "That is Dick's natural personality—to be somewhat of a contrarian," Wallace says. "He feels he can work the argument and win."

Lindzen is also accustomed to charting his own course and trusting what his brain seems to tell him. Raised in the Bronx by immigrant parents, Lindzen graduated from the Bronx High School of Science in 1956, started college at Rensselaer Polytechnic Institute, then transferred to Harvard after two years, graduating in 1960 with a bachelor's degree in physics. He didn't intend to specialize in climatology when he stayed at Harvard to pursue a graduate degree, but he won a fellowship in atmospheric and ocean science that allowed him to continue studying his first love: applied mathematics and physics.

Early on, Lindzen's exceptional math skills helped shape his career. For a series of papers he published in the late sixties and early seventies, he chose to tackle a complex phenomenon involving thermal currents in the atmosphere that scientists had been trying to explain for decades. "Lindzen figured out how to mathematically solve the problem," says Wallace. In 1977, this work helped get Lindzen elected to both the National Academy of Sciences and the American Academy of Arts and Sciences. He was awarded an endowed professorship at MIT in 1983.

In 1990, two years after NASA scientist James E. Hansen issued his now famous warning about climate change during a congressional hearing, Lindzen started taking a publicly contrarian stance when he challenged then-senator Gore by suggesting in the Bulletin of the American Meteorological Society that the case for human-induced global warming was overstated and that natural climate variability could explain things just as easily. In 1992, he served up similar arguments at a Vienna conference on the science and economics of global warming that was hosted by OPEC and marked by unruly protests from environmentalists.

Lindzen tends to relate these stories with mild sarcasm, implying that the listener is surely sophisticated enough to perceive his opponents' foibles. "They were actually trying to climb in the building," he recalls in a deadpan tone. "It was kind of strange, but these were Europeans."

Lindzen's critiques usually focus on how current climate models can't explain everything and how their proponents conveniently ignore facts that don't fit their assumptions. He points out, for example, that there's been a period of global cooling since the 18th-century onset of the Industrial Revolution—from the 1940s to the 1960s—and that average temperatures rose in Europe between 1050 and 1300, even though there was no heavy industry going on back then.

At the moment, Lindzen is pursuing a theory that says increased amounts of water vapor—from warming surface temperatures—will reduce heat-trapping high-cirrus clouds, which will help balance the planet's temperature. This concept is significant, because most climate scientists believe water vapor will exacerbate the warming effect of greenhouse gases. Lindzen and some scientists at NASA have offered a hypothesis that warming in the tropics will reduce high-cirrus cloudiness there, which will increase outgoing heat more than it increases the heating effect of incoming sunlight. While this theory has sparked serious academic debate, most experts took a pass after a group of researchers criticized it in a 2002 paper for the Journal of Climate.

Stanford University climatologist Stephen H. Schneider, who helped write an important chapter of the IPCC report on global warming's potential impact, has debated Lindzen frequently in academic forums and compares his critique to the traditional scientific method of Karl Popper, which involves testing a theory by looking for flaws. But Lindzen has gone too far, Schneider says, because, given the complexity of the subject, it makes no sense to focus on a few unexplained aspects of human-induced warming when the overwhelming indicators—along with current temperature and weather patterns—suggest that the theory is right.

Schneider recognizes that global warming may not wreak catastrophic change—in fact, he puts the chances at roughly 50-50. But given those odds, he argues, we're better off acting as if catastrophic warming is a 100 percent lock. "The chance of an asteroid hitting the planet is one in a hundred million, so we don't worry about that," he says. "Significant climate change is a coin flip, so we do."

Many critics don't give Lindzen as much credit as Schneider does, suggesting that he's a tool for Big Oil. In 1995, Ross Gelbspan, writing in Harper's, pointed out that in 1991 Lindzen testified before Congress as an expert witness and that the Western Fuels Association, an industry group, paid his trip expenses to Washington.

While Lindzen did accept the expenses, this doesn't mean he's on anybody's payroll. He charges for his speeches, but so do prominent scientists who disagree with him about climate change. (Lindzen gets between $5,000 and $10,000 for speaking to a corporate group and between $1,000 and $2,000 for noncorporate gigs like the Coast Guard Academy appearance.) As his friend Wallace would attest, his main motive is conviction. He's sure he's right, and he revels in his contrary ways.

This is, after all, a chain smoker who thinks the evidence linking secondhand smoke to lung cancer is iffy. With a wife and two grown sons, he lives the classic, comfortable life of a New England professor, residing in a wooden clapboard house in Newton, Massachusetts, filled with shelves crammed with books and LPs of classical music, opera, jazz, folk, and musical comedy. He remained a Democrat until 1991, even as he questioned whether global warming mattered, switching to the GOP only after many prominent Democrats had excoriated him.

Lindzen doesn't have any use for most environmentalists, and even when he does something "green," he sniffs at the idea that he's following their lead. He uses compact fluorescent lightbulbs in many of his lamps at home but emphasizes, "It's not to save the world. It's to save on our electric bills."