Climate scientist Michael Mann has been awarded $1 million in a defamation lawsuit by a jury.

Climate scientist Michael Mann has been awarded $1 million in a defamation lawsuit by a jury.

A court has granted $1 million to climate scientist Michael Mann in a lawsuit he filed against two conservative writers 12 years ago. They had likened his portrayal of global warming to that of a convicted sex offender.

According to Mann, a climate science professor at the University of Pennsylvania, his graph first appeared in the journal Nature in 1998 and became known as the “hockey stick” due to its striking depiction of a heating earth.

Mann’s work gained him widespread recognition, but also attracted numerous doubters. This included two writers who Mann took legal action against for remarks that he believed negatively impacted his professional standing and reputation both in the United States and abroad.

“I am thrilled,” Mann expressed on Thursday following the verdict from the six-person jury. “This is a positive day for us, and for the field of science.”

In 2012, an organization called the Competitive Enterprise Institute, known for its libertarian beliefs, released a blog post written by Rand Simberg, who was a fellow at the time. The post drew comparisons between the investigations of Michael Mann’s work and the case of Jerry Sandusky, a former assistant football coach at Penn State University who was found guilty of sexually assaulting several children. It is worth noting that Mann was also employed at Penn State during this time.

In 2009, the release of emails belonging to Mann and other scientists sparked an investigation into his research. This incident raised doubts about the accuracy of the “hockey stick” graph, with some skeptics accusing Mann of tampering with data. However, inquiries conducted by Penn State and other institutions concluded that Mann did not misuse data. Nevertheless, his work has faced criticism, particularly from conservative groups.

Simberg claimed that Mann is comparable to Jerry Sandusky in the field of climate science, but instead of abusing children, he has manipulated and distorted data. In another article, Mark Steyn referenced Simberg’s piece and accused Mann’s research of being fraudulent in National Review.

The Superior Court of the District of Columbia’s jury concluded that Simberg and Steyn had made untrue remarks. As a result, Mann was granted $1 in compensatory damages from each writer. Additionally, Simberg was ordered to pay $1,000 in punitive damages and Steyn was ordered to pay $1 million, as the jury determined that their statements were made with malicious intent to harm.

Steyn acted as his own representative during the trial, but relayed through his manager Melissa Howes that he plans to contest the $1 million punitive damages award, citing the need for a thorough review of the due process.

During the trial, Mann claimed that his blog posts caused him to lose grant funding. However, both defendants argued that Mann did not provide enough evidence to support this claim. They also pointed out that Mann’s reputation as a leading climate scientist only grew after their comments were made.

Steyn’s manager stated on Thursday that they had always maintained that Mann did not experience any real harm from the statement in question. After 12 years, the jury has now awarded him one dollar in compensatory damages.

Mark DeLaquil, the attorney for Simberg, stated that his client was dissatisfied with the verdict and plans to challenge the jury’s ruling.

Both authors maintained that they were simply expressing their viewpoints.

According to Lyrissa Lidsky, a professor of constitutional law at the University of Florida, the jury’s decision suggests that Steyn and Simberg were aware of the falsehood of their statements and acted recklessly. Lidsky also noted that the difference between the amount awarded for compensatory and punitive damages could lead to the judge decreasing the punitive damages.

For years, numerous scientists have been monitoring Mann’s situation due to the spread of misinformation about climate change on certain social media sites.

Kate Cell, senior climate campaign manager at the Union of Concerned Scientists, expressed her hope that individuals will carefully consider their actions before spreading false information and damaging the reputation of scientists. As part of her role, she monitors and addresses misinformation surrounding climate change.

Cell expressed his hope that the verdict will serve as a means for us to return to a civil discussion based on facts.

The judge in charge of the case, Alfred Irving, reminded the jury on Wednesday, before they began deliberating, that their role was not to determine the existence of global warming.

The issue of climate change remains a source of contention and strong political divisions in the United States. According to a 2023 survey conducted by The Associated Press-NORC Center for Public Affairs Research, 91% of Democrats acknowledge the existence of climate change, compared to only 52% of Republicans.

Mann announced on Thursday that he plans to challenge a ruling made in 2021 by the D.C. Superior Court, which found National Review and the Competitive Enterprise Institute not responsible for defamation in the same situation.

Mann stated that the decision was incorrect and that they will be addressing it next.


The AP’s reporting on climate and the environment is funded by various private foundations. The AP is solely responsible for all of its content. You can find the AP’s guidelines for collaborating with philanthropic organizations, a list of supporters, and the coverage areas that have been funded on