If the theory of man-made global warming were such a self-obvious truth, the result of scientific consensus, then why do advocates for this idea keep committing frauds to advance it? Even more disturbing, why are some writers willing to defend this behavior?

The latest embarrassment for global-warming activists came on Feb. 20 after Peter Gleick, founder of the Pacific Institute for Studies in Development, Environment and Security in Oakland, admitted that he committed fraud to obtain documents he thought would embarrass a conservative think tank that has been a leading debunker of some of the overheated claims of the climate-change Chicken Littles.

The memos, which reveal the group's political and fund-raising strategies, provided little to embarrass the Chicago-based Heartland Institute, but it has damaged the reputation of a man who was a respected intellectual in the environmental world. Gleick, a MacArthur Foundation "genius" fellow, doesn't seem brilliant now, as he takes a leave of absence from the institute, faces public embarrassment and possible prosecution. (Heartland claims that one memo was fabricated, although Gleick denies that charge, but the scandal could get uglier.)

But even after Gleick admitted and apologized for his action, Los Angeles Times columnist Michael Hiltzik defended him: "It's a sign of the emotions wrapped up in the global warming debate that Gleick should be apologizing for his actions today while the Heartland Institute stakes out the moral high ground."

"Peter Gleick lied, but was it justified by the wider good?" asked James Garvey of the British Guardian newspaper. He compared Gleick's action to that of a man who lied to keep his friend from driving home drunk. "What Heartland is doing is harmful, because it gets in the way of public consensus and action," he argued. "If his lie has good effects overall—if those who take Heartland's money to push skepticism are dismissed as shills, if donors pull funding after being exposed in the press—then perhaps on balance he did the right thing. … It depends on how this plays out."

In his view, anything that gets in the way of "consensus"—i.e., everyone agreeing with Garvey—is dangerous, so why not cheat, as long as it "has good effects"? Let's reserve judgment based on how it plays out.

What would these people argue if a conservative who argues that, say, public-sector unions are bankrupting the state, pulled a similar fraud to get his hands on documents from union officials? Would they be defending that? Of course not. These writers are advancing a Machiavellian political agenda, not advancing a consistent ethical principle.

When it comes to global warming, the ends apparently justify the means. People from all political persuasions do stupid things to advance their cause, but what bothers me most are respectable people who justify behavior they would never tolerate from their foes. That type of ideological fanaticism is corrosive of our democratic society.

It's easy to chide the hypocrisy of Gleick. He had been the chairman of an ethics committee for a scientific association. His column blasting dishonesty still sits on his institute's Web site. It's harder to explain away his deceit as a mere aberration in the climate-change drama.

In the "Climategate" scandal in 2009, "Hundreds of private email messages and documents hacked from a computer server at a British university are causing a stir among global warming skeptics, who say they show that climate scientists conspired to overstate the case for a human influence on climate change," according to a New York Times report from the time. The emails showed that the scientific community is so invested in this climate-change ideology for financial and ideological reasons that it rather cook the numbers than level with the public about the reality of the threat. A follow-up release of emails in 2011 provided even more evidence supporting skeptics' claims.

In this scandal, Gleick created a bogus email account in which he pretended to be a Heartland board member. Then he contacted the organization and asked for documents from a recent board meeting. He released them on the Internet anonymously and to journalists while claiming to be a Heartland insider, according to the institute's explanation.

Although he offered his regrets, Gleick's mea culpa was laden with excuses: "I only note that the scientific understanding of the reality and risks of climate change is strong, compelling, and increasingly disturbing, and a rational public debate is desperately needed. My judgment was blinded by my frustration with the ongoing efforts—often anonymous, well-funded, and coordinated—to attack climate science and scientists and prevent this debate, and by the lack of transparency of the organizations involved."

How do you base a "rational public debate" on deceit?

It's not as if the documents added anything to the debate. They didn't show any enormous investment by big corporations. They proved, as one writer noted, that donors give money to organizations whose work they endorse. What a revelation. Isn't that what happens on the environmental side, also?

Marc Gunther of The Energy Collective admitted that "the leaked Heartland documents didn't prove very much." He slammed allies in the global-warming movement for praising Gleick and comparing him to a whistleblower. Clearly, not all believers in man-made global warming defend the indefensible.

But there is something about global warming that attracts the "ends justify the means" crowd. It's the same fraudulent ideology that California's state government has embraced as it implements a first-in-the-nation cap-and-trade program that won't do a thing to cool our state, but will raise taxes on businesses and drive many of them elsewhere. Advocates of AB32 were hardly fonts of honesty and rational debate.

Hey, if Planet Earth is in danger, then anything goes in the political realm also. That ideology is far scarier to me than a little warmer weather.

Steven Greenhut is vice president of the Franklin Center for Government and Public Integrity.