Michael Mann, a climate professor and former vice provost at the University of Pennsylvania, must pay $28,167.62 in attorneys’ fees for two conservative writers he accused of defamation for criticizing his work.
In a Thursday ruling, Judge Alfred S. Irving of the Superior Court of the District of Columbia wrote that the compensation was necessary because Mann repeatedly misled the jury during the case’s 2024 trial. Mann presented information that he lost more than $9.7 million in research grant funding as a result of the two writers’ criticism, a figure that was later corrected to $112,000 following a third round of discovery.
"The Court simply cannot condone such bad faith litigation tactics, particularly in a case that had been zealously litigated across several years and a case involving complicated facts," Irving wrote. "It is the Court's duty to punish and deter bad faith litigation tactics."
Irving chastised Mann, adding that the lost grant funding figures were central to his case and that it was ultimately his responsibility to ensure the facts of his case "were presented truthfully and straightforwardly."
It’s the latest blow for the embattled scientist whom Irving last year sanctioned and ordered to pay more than $1 million in attorneys’ fees to the two defendants in the case, Rand Simberg, a then-adjunct fellow at the right-leaning think tank Competitive Enterprise Institute, and Mark Steyn, a then-writer for National Review.
Mann—who is perhaps best known for his 1998 "hockey stick graph" showing the Earth warming at a rapid rate and is regularly cited by mainstream media outlets—filed the defamation lawsuit in 2012 against Simberg and Steyn. Months earlier, Simberg authored a blog that used a metaphor comparing how Mann’s then-employer, Pennsylvania State University, defended his climate research to how the university allegedly covered up child sexual abuse accusations against assistant football coach Jerry Sandusky.
Steyn then referenced that blog in a piece of his own slamming Mann’s work.
Both of the articles came three years after email correspondence between Mann and other climate scientists was leaked. Simberg and Steyn argued the emails showed Mann had engaged in data manipulation when creating his "hockey stick graph."
Following the February 2024 trial in which Mann presented the misleading information in the case, a D.C. jury awarded Mann a staggering $1 million in punitive damages to be paid by Simberg and Steyn. However, in his order sanctioning Mann last year, Irving threw out that penalty, characterizing it as excessive.
Mann resigned from his post as vice provost at the University of Pennsylvania in September after he shared a social media post comparing Charlie Kirk to a member of the "Hitler Youth." He had served in the role for less than a year.
The posts about Kirk weren’t Mann’s first time engaging in heated political rhetoric.
Last year, he appeared to threaten President Donald Trump, writing on social media that "we're in second amendment territory" if the president doesn't comply with a federal court injunction. In 2023, he compared Republican donors Peter Thiel, Charles Koch, and Leonard Leo to Osama bin Laden and the al Qaeda 9/11 assailants. And a year earlier, he wrote that the Republican Party "needs to be destroyed."
Mann remains a professor at the University of Pennsylvania and is its director of the Center for Science, Sustainability, and the Media.
The University of Pennsylvania did not respond to requests for comment.
