Mann, who will remain a professor at the Ivy League university, has courted controversy with a series of public outbursts in recent months
The left-wing climate scientist and political activist Michael Mann resigned on Tuesday from his post as vice provost at the University of Pennsylvania. Mann stirred up controversy repeatedly over the past several months, most recently when he shared a social media post that compared Charlie Kirk to a member of the “Hitler Youth.” Mann will remain at the university as a professor and the director of its Center for Science, Sustainability, and the Media.
Mann explained in a blog post Monday that his environmental advocacy work “at times feels in conflict” with the University of Pennsylvania’s institutional neutrality policy. “At this moment in time, I don’t feel that I can forsake the public scholarship and advocacy that I am doing and have thus decided to step down from the VPC role,” he wrote.
Though Mann cited his recent work with staunch vaccine defender Peter Hotez as an example of that advocacy work, he has faced criticism in recent months over his public outbursts. Sen. Dave McCormick (R., Pa.) called for the University of Pennsylvania to take “immediate, decisive action” against Mann following his tirade against Kirk earlier this month.
A day after Kirk’s assassination, Mann attacked a New York Times editorial titled, “Charlie Kirk Was Practicing Politics the Right Way.” At one point, Mann reposted a comment likening Kirk to a Nazi. And after police identified Kirk’s killer, Mann joked that “white on white violence has gotten out of hand.”
“This is despicable behavior. This dangerous rhetoric cannot and will not be tolerated. I unequivocally condemn this behavior,” wrote McCormick.
In May, Mann warned the United States would be in “second amendment territory” if Trump didn’t comply with a federal court injunction blocking a plan to dismantle the Department of Education. He then attempted to defend his apparent threat, stating the Second Amendment “refers to the right of the people to rise up and defend democracy.” He eventually deleted the post altogether.
It is unclear whether University of Pennsylvania leadership forced Mann to resign. The university did not respond to a request for comment.
Mann’s resignation, meanwhile, comes less than a year after the university gave him the position. He was named its inaugural vice provost for climate science, policy, and action in October 2024.
In addition, Mann has faced legal setbacks this year. A Washington, D.C., court ordered him to pay more than $1 million to cover litigation costs for the Competitive Enterprise Institute and National Review, two entities he has accused of libel.
Mann is perhaps best known for his “hockey stick” graph published in 1998 showing global temperatures have spiked since humans started relying on fossil fuels. That research has been used by the United Nations, climate groups, and activists to show governments must rapidly abandon oil, gas, and coal if they want to stave off cataclysmic global warming.
The graph has faced pushback from experts who say Mann’s research was filled with statistical errors and relied too heavily on tree ring data from just a few regions.
