In a surprising legal development, the defamation case involving climate scientist Michael Mann has been overturned, raising questions about the intersection of climate science and defamation law.

A judge vastly reduced climate researcher Michael Mann’s award, sanctioned his lawyers for presenting false evidence and ordered him to pay $530,000.

For defenders of climate science, the court ruling was a big victory in the fight against misinformation.

Michael Mann, one of the country’s most prominent climate scientists, won more than $1 million last year in a defamation case. A jury found that two conservative commentators had defamed him by alleging that he was like a child molester in the way he had “molested and tortured” climate data.

Now, a year after that ruling, the case has taken a turn that leaves Mann in the position of the one who owes money.

On Wednesday, a judge sanctioned Mann’s legal team for “bad-faith trial misconduct” for overstating how much the scientist lost in potential grant funding as a result of reputational harm.

The lawyers had shown jurors a chart that listed one grant amount Mann didn’t get at $9.7 million, though in other testimony Mann said it was worth $112,000. And when comparing Mann’s grant income before and after the negative commentary, the lawyers cited a disparity of $2.8 million, but an amended calculation pegged it at $2.37 million.

D.C. Superior Court Judge Alfred S. Irving Jr., who was appointed to the bench by President George W. Bush, called the conduct “an affront to the Court’s authority and an attack on the integrity of the proceedings.”

Earlier this month, the same judge threw out the $1 million penalty owed by one of the writers, Mark Steyn. The verdict against Steyn had been “grossly excessive,” said Irving, who reduced the damages to $5,000.

And in January, the court ordered Mann to pay more than $530,000 in legal expenses to National Review, one of the publishers of the commentary, under rules meant to prevent critics from being burdened with the cost of a legal defense.

These developments amount to a remarkable reversal in legal fortunes for Mann, best known for his “hockey stick” chart showing how global temperatures have risen sharply since humans began burning massive amounts of fossil fuels during the Industrial Revolution.

Steyn’s team said the recent rulings are a victory for free speech and evidence that Mann’s defamation claims were without merit. “[F]inally — the lies caught up with him,” Steyn’s manager, Melissa Howes, wrote of Mann on Steyn’s website this week.

But the climate scientist’s legal team said it was preparing to fight the setbacks in court. Peter J. Fontaine, one of Mann’s attorneys, wrote in an email that Mann “believes that the court committed errors of fact and law and will pursue these matters further.”

Fontaine emphasized that the original decision — that Mann was defamed by the commentary — still stands. “We have reviewed the recent rulings by the D.C. Superior Court and are pleased to note that the court has upheld the jury’s verdict,” he said.

The original case centered on a pair of short blog posts published in 2012.

One of the commentators, Rand Simberg, wrote on the website of the Competitive Enterprise Institute that “Mann could be said to be the Jerry Sandusky of climate science, except that instead of molesting children, he has molested and tortured data in the service of politicized science.” Sandusky, a former Pennsylvania State University football coach, was convicted of molesting young boys. Mann taught at Penn State at the time.

Steyn subsequently quoted the article in National Review, adding: “Not sure I’d have extended that metaphor all the way into the locker-room showers with quite the zeal Mr. Simberg does, but he has a point.”

Mann sued both the publishers and the bloggers, saying they falsely accused him of academic fraud and caused him emotional distress and the loss of grant funding.

The court dropped Mann’s case against National Review and the Competitive Enterprise Institute, but allowed it to proceed against the two bloggers themselves. In a trial in early 2024 lasting more than three weeks, a jury agreed with several of Mann’s claims against Steyn and Simberg, awarding the scientist more than $1 million in damages.

“I hope this verdict sends a message that falsely attacking climate scientists is not protected speech,” Mann, now a professor at the University of Pennsylvania, said at the time.

After the court action this week, National Review editor Rich Lowry wrote in an email, “We said from the very beginning that Mann’s suit was meritless and it’s gratifying to see it really begin to fall apart, if much too late.”

https://www.washingtonpost.com/climate-environment/2025/03/14/michael-mann-climate-lawsuit-defamation/