The U.S. Senate's leading abuser of science has struck again. Not content with calling the notion of human-caused global warming "the greatest hoax ever perpetrated on the American people" (as he did in a July 2003 Senate floor speech), last week James Inhofe returned with an "update" on climate-change science. In his latest speech, timed to coincide with the final steps toward implementation of the Kyoto Protocol (which the United States won't be joining), Inhofe asserted that "put simply, man-induced global warming is an article of religious faith." Clearly, he hasn't changed his tune.

What separates Inhofe's fixation from similar conservative crusades is just how brazenly it ignores what scientists know with confidence about global warming. The United Nations' Intergovernmental Panel on Climate Change (IPCC), the National Academy of Sciences, the American Geophysical Union, and the American Meteorological Society all broadly agree on this basic point: Temperatures are rising, at least in part as a result of human greenhouse-gas emissions. According to the World Meteorological Organization, 2004 was the fourth-hottest year since 1861, while the past 10 years (excepting 1996) were "among the warmest 10 years on record."

That's not all. Drawing on highly sophisticated computer models, climate scientists can project -- not predict -- how much temperatures may rise by, say, 2100 if we carry on with business as usual. Although scenarios vary, some get pretty severe. So do the projected impacts of climate change: rising sea levels, species extinctions, glacial melting, and so forth.

One might argue, perhaps, that humanity should simply adapt to climatic changes rather than restricting fossil-fuel use. But that's not Inhofe's approach. No matter how strong the evidence of ongoing climate change gets, he simply rejects it. But backed into a corner, Inhofe's arguments have necessarily grown more and more desperate.

For example, in his latest speech, Inhofe continued his curious crusade against a single University of Virginia climate expert, Michael Mann. Mann initially became a target for global warming "skeptics" in 2001 after the IPCC prominently cited his work to show that recent temperatures represent an anomaly in the context of the past 1,000 years. The IPCC reproduced a graph published by Mann and his colleagues that's often referred to as a "hockey stick" because of its shape: After a long, relatively straight line, temperatures spike up in the 20th century.

Ever since then, global warming deniers (and especially Inhofe) have been trying to break the "hockey stick," but their attacks on Mann represent a grand diversion. Although in his latest speech Inhofe refers only to "the hockey stick graph, constructed by Dr. Michael Mann and colleagues," multiple other scientists have produced similar analyses. And even if all of these were to be overturned, that would hardly upend the conclusion that humans are currently heating the planet -- a robust scientific finding based on several different lines of evidence. Rather, shattering the "hockey stick" would merely leave us uncertain as to whether the current temperature spike has any precedent over the past millennium.

In fact, Inhofe's latest foray against Mann throws into question the competence of the senator's scientific-research apparatus. Inhofe charged that recent critics, arguing in the scientific literature, have called Mann's hockey-stick work "just bad science." But the critics in question weren't attacking the "hockey stick" at all. Rather, they were challenging an entirely different paper by Mann and a colleague, and the disagreement concerns the period between 1971 and 1998 -- not the past 1,000 years. It looks as though Inhofe went rifling through the scientific literature to find someone criticizing Michael Mann without even bothering to understand the context of that criticism.

Yet Inhofe's latest speech stoops even lower than this. The senator also implied, on the slender basis of a Washington Post cartoon (which he misinterprets), that some "alarmists" think climate change triggered the recent Asian tsunami. "Are we to believe now that global warming is causing earthquakes?" Inhofe asked rhetorically.

Answer: No, we aren't to believe that. No one believes that.

In criticizing environmental "alarmists" for something that none of them have said, Inhofe has created as big a straw man as we've seen in politics lately. Yet when it comes to climate change, Inhofe doesn't seem to care whether he has a sound argument to make, so long as he has something contrary to say that takes at least some effort to deconstruct.

Let's take one more glance at the way Inhofe abuses climate science. In his latest speech, Inhofe took aim at a recently released report from the Arctic Climate Impact Assessment, produced by some 300 scientists working under the auspices of the Arctic Council (an intergovernmental group that includes the United States). The report shows that human-caused climate change has already had a pronounced effect in the Arctic region, where average temperatures have shot up "at almost twice the rate as the rest of the world in the past few decades." The result? Ongoing impacts such as melting glaciers and sea ice.

These conclusions come from a body of scientific experts who have studied the problem for four years. What does James Inhofe do when faced with such a major, peer-reviewed scientific consensus document? The same thing he always does: He draws on a tiny number of skeptic scientists, here pointing out that Arctic temperatures in the 1930s and 1940s rival those today, to challenge the consensus. But while 1930s and 1940s Arctic temperatures were probably caused by natural variation, today's temperature spike seems to have a human fingerprint. That's the whole point.

Throughout his speech, moreover, Inhofe made constant reference to a work of fiction: Michael Crichton's new novel, State of Fear. Calling Crichton a "scientist" -- actually, he's an M.D. -- Inhofe credited the author with telling "the real story about global warming" to the public. In fact, Crichton's new book misrepresents climate science nearly as badly as Inhofe does. Inhofe further suggested that Crichton's depictions of environmentalists -- as fear-mongers who hype the possibility of disasters to bring in donations -- show "art imitating life." Actually, Crichton's notion of a global eco-terrorist conspiracy, aided and abetted by leading environmental organizations, seems more than a tad conspiratorial.

Nevertheless, we haven't heard the last from Senator Crank. Speaking of the remaining cadre of climate-science "skeptics," Inhofe pledged in his latest speech: "I will do my part to make sure that they are heard." In other words, he will continue to challenge each new major piece of scientific evidence on climate, raising dubious criticisms rather than trying in earnest to understand the best science. And this is the chairman of the Senate Committee on Environment and Public Works talking.

Chris Mooney is a Prospect senior correspondent. His book on the politicization of science will be published later this year by Basic Books. His daily blog and other writings can be found at www.chriscmooney.com.