Michael Mann’s $1 Million Defamation Verdict Resonates in a Still-Contentious Climate Science World

In winning a $1 million verdict against a pair of right-wing bloggers on Thursday, climate scientist Michael Mann scored a victory that is reverberating through a world of climate discourse that many say is no less disputatious than when the bloggers penned their attacks 12 years ago.

“I hope this verdict sends a message that falsely attacking climate scientists is not protected speech,” Mann said in a statement following the unanimous decision of a six-person jury in the Superior Court of the District of Columbia. 

After a four-week trial, the panel deliberated for a day before delivering its decision that Mann had been defamed by Rand Simberg, a former adjunct scholar at the Competitive Enterprise Institute, and Mark Steyn, a contributor to National Review. The jury awarded Mann $1 in compensatory damages and $1 million in punitive damages.The bloggers alone faced the judgment; a court three years ago ruled that the publishers could not be held liable for the writings of their part-time contributors.

Although the heyday of blogging is long past, and the consensus on global warming has grown stronger in the dozen years since Mann launched his case, climate scientists continue to face personal and professional attacks in the polarized battle over the future of fossil fuels.

Lauren Kurtz, executive director of the Climate Science Legal Defense Fund, said the New York-based group provided legal support to a record number of clients in 2023—32 individuals and groups, according to its annual report. And although she has heard from scientists that they found news of the Mann verdict gratifying, Kurtz said she did not expect that it would change the beliefs of climate deniers or put an end to attacks on scientists.

“It’s unusual to see a scientist fight back as much as Michael Mann has fought back,” she said. “I think a lot of people don’t realize the extent to which other climate scientists are being targeted, and for valid personal and professional reasons, are not able to take on this level of publicity in defending themselves.”

Cases that have come to the Defense Fund involved defamation threats for publishing new research, fears of employer retaliation for public speaking on climate change, and invasive open records inquiries—the kind that Mann himself faced earlier in his career. 

For example, the Legal Defense Fund’s annual report said in 2023 it represented a professor at a public university who found herself the target of a subpoena from an oil and gas company that was asking her to turn over her research on the potent greenhouse gas methane. The Defense Fund did not name the professor, but said that by representing her pro bono, it was able to protect her from the company’s move, which it characterized as “an obvious attempt to silence and discredit her.”

In the case decided this week, Mann faced a more blatant attack. In separate blogs, Simberg and Steyn drew comparisons between Mann’s science and a child sex abuse scandal that had jolted the institution where he taught at the time, Pennsylvania State University. They wrote that Mann had “molested and tortured data,” and that the school had engaged in a “whitewash” of his science, much as it had failed to unearth the transgressions of Penn State’s disgraced assistant football coach, Jerry Sandusky.

Mann said on the witness stand that he was made to feel like a “pariah” in the community and also saw his research grant funding plummet. Mann has authored some of the most influential science on climate change, including the so-called “Hockey Stick” graph depicting the dramatic temperature rise since the dawn of the Industrial Age.

As a public figure, Mann, who now directs a Center for Science, Sustainability and the Media at the University of Pennsylvania, faced a high burden of proof to show that the blogs rose to the level of defamation. Under long-standing Supreme Court precedent, he had to show the defendants acted with knowing falsehood or reckless disregard for the truth. But the jury decided that Mann cleared that hurdle, after a trial in which Steyn, a native of Canada, declared, “I did not appraise myself of the details of your American investigations,” before he slammed the scientist in print.

After the verdict, Steyn posted on the social media platform X, “A Bad Day for America,” and linked to a piece on his website, Steynonline.com. It reads, in part, “Putting aside the monetary damages, the real damage done by this case is to every American who still believes in the First Amendment.” The decision has not silenced Steyn; he posted that he would answer questions from “Mark Steyn Club” members live online on Friday “at 3 p.m. Deep State Standard Time.”

Postings on his website indicate that Steyn intends to appeal; the preview for his Q&A noted the $1 million “will likely get overturned at the United States Supreme Court,” and another article quoted extensively from the dissent that Justice Samuel Alito wrote in 2019 when the Supreme Court previously refused to hear an appeal that would have blocked Mann’s case. 

Since then, the high court has gained one more conservative vote, that of Associate Justice Amy Coney Barrett. But it is not clear how much support Alito has for Mann’s view that the efforts to compare him to a convicted child molester was a threat to “robust and uninhibited debate on important political and social issues.”