• Home
  • Latest
  • Fortune 500
  • Finance
  • Tech
  • Leadership
  • Lifestyle
  • Rankings
  • Multimedia
Environmentclimate change

‘It’s a good day for science’: Penn scientist famous for ‘hockey stick’ graph on climate change wins $1 million verdict on defamation claims

By
Suman Naishadham
Suman Naishadham
and
The Associated Press
The Associated Press
Down Arrow Button Icon
By
Suman Naishadham
Suman Naishadham
and
The Associated Press
The Associated Press
Down Arrow Button Icon
February 9, 2024, 8:19 AM ET
Michael Mann
Michael Mann.Evan Agostini—Invision/AP

A jury on Thursday awarded $1 million to climate scientist Michael Mann who sued a pair of conservative writers 12 years ago after they compared his depictions of global warming to a convicted child molester.

Recommended Video

Mann, a professor of climate science at the University of Pennsylvania, rose to fame for a graph first published in 1998 in the journal Nature that was dubbed the “hockey stick” for its dramatic illustration of a warming planet.

The work brought Mann wide exposure but also many skeptics, including the two writers Mann took to court for comments that he said affected his career and reputation in the U.S. and internationally.

“It feels great,” Mann said Thursday after the six-person jury delivered its verdict. ”It’s a good day for us, it’s a good day for science.”

In 2012, a libertarian think tank named the Competitive Enterprise Institute published a blog post by Rand Simberg, then a fellow at the organization, that compared investigations into Mann’s work to the case of Jerry Sandusky, a former assistant football coach at Penn State University who was convicted of sexually assaulting multiple children. At the time, Mann also worked at Penn State.

Mann’s research was investigated after his and other scientists’ emails were leaked in 2009 in an incident that brought further scrutiny of the “hockey stick” graph, with skeptics claiming Mann manipulated data. Investigations by Penn State and others found no misuse of data by Mann, but his work continued to draw attacks, particularly from conservatives.

“Mann could be said to be the Jerry Sandusky of climate science, except for instead of molesting children, he has molested and tortured data,” Simberg wrote. Another writer, Mark Steyn, later referenced Simberg’s article in his own piece in National Review, calling Mann’s research “fraudulent.”

The jury in Superior Court of the District of Columbia found that Simberg and Steyn made false statements, awarding Mann $1 in compensatory damages from each writer. It awarded punitive damages of $1,000 from Simberg and $1 million from Steyn, after finding that the pair made their statements with “maliciousness, spite, ill will, vengeance or deliberate intent to harm.”

During the trial, Steyn represented himself, but said through his manager Melissa Howes that he would be appealing the $1 million award in punitive damages, saying it would have to face “due process scrutiny.”

Mann argued that he had lost grant funding as a result of the blog posts — an assertion for which both defendants said Mann did not provide sufficient evidence. The writers countered during the trial that Mann instead became one of the world’s most well-known climate scientists in the years after their comments.

“We always said that Mann never suffered any actual injury from the statement at issue,” Steyn said on Thursday through his manager. “And today, after twelve years, the jury awarded him one dollar in compensatory damages.”

Simberg’s attorney Mark DeLaquil said his client was “disappointed in the verdict” and would appeal the jury’s decision.

Both writers argued that they were merely stating opinions.

Lyrissa Lidsky, a constitutional law professor at the University of Florida, said it was clear the jurors found that Steyn and Simberg had “recklessly disregarded the falsity of their statements.” She added that the discrepancy between what the jury awarded in compensatory and punitive damages could result in the judge reducing the punitive damages.

Many scientists have followed Mann’s case for years as misinformation about climate change has grown on some social media platforms.

“I hope people think twice before they lie and defame scientists,” said Kate Cell of Union of Concerned Scientists. Her work as senior climate campaign manager includes tracking misinformation related to climate change.

“We are so far outside the bounds of a civil conversation about facts that I hope this verdict can help us find our way back,” Cell said.

Alfred Irving, the judge presiding over the case, reminded the jury on Wednesday before they deliberated that their job was not to decide “whether there’s global warming.”

Climate change continues to be a divisive and highly partisan issue in the United States. A 2023 poll from The Associated Press-NORC Center for Public Affairs Research found that 91% of Democrats believe climate change is happening, while only 52% of Republicans do.

On Thursday, Mann said he would be appealing a 2021 decision reached in D.C. Superior Court that held National Review and the Competitive Enterprise Institute not liable for defamation in the same incident.

“We think it was wrongly decided,” Mann said. “They’re next.”

___

The Associated Press’ climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP’s standards for working with philanthropies, a list of supporters and funded coverage areas at AP.org.

Join us at the Fortune Workplace Innovation Summit May 19–20, 2026, in Atlanta. The next era of workplace innovation is here—and the old playbook is being rewritten. At this exclusive, high-energy event, the world’s most innovative leaders will convene to explore how AI, humanity, and strategy converge to redefine, again, the future of work. Register now.
About the Authors
By Suman Naishadham
See full bioRight Arrow Button Icon
By The Associated Press
See full bioRight Arrow Button Icon

Latest in Environment

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025

Most Popular

Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Finance
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam
By Fortune Editors
October 20, 2025
Rankings
  • 100 Best Companies
  • Fortune 500
  • Global 500
  • Fortune 500 Europe
  • Most Powerful Women
  • Future 50
  • World’s Most Admired Companies
  • See All Rankings
Sections
  • Finance
  • Leadership
  • Success
  • Tech
  • Asia
  • Europe
  • Environment
  • Fortune Crypto
  • Health
  • Retail
  • Lifestyle
  • Politics
  • Newsletters
  • Magazine
  • Features
  • Commentary
  • Mpw
  • CEO Initiative
  • Conferences
  • Personal Finance
  • Education
Customer Support
  • Frequently Asked Questions
  • Customer Service Portal
  • Privacy Policy
  • Terms Of Use
  • Single Issues For Purchase
  • International Print
Commercial Services
  • Advertising
  • Fortune Brand Studio
  • Fortune Analytics
  • Fortune Conferences
  • Business Development
About Us
  • About Us
  • Editorial Calendar
  • Press Center
  • Work At Fortune
  • Diversity And Inclusion
  • Terms And Conditions
  • Site Map

Latest in Environment

Elicker
LawCrime
New Haven mayor says police chief admitted to stealing money from department, accepts retirement
By The Associated PressJanuary 6, 2026
2 days ago
trump
PoliticsRare Earth Metal
Why Greenland appeals to Trump’s real-estate investor heart: location, location, location
By Danica Kirka and The Associated PressJanuary 6, 2026
2 days ago
data center
AIData centers
Angry town halls nationwide find a new villain: the data center driving up your electricity bill while fueling job-killing AI
By Marc Levy and The Associated PressJanuary 3, 2026
5 days ago
EnvironmentWhite House
‘I want nice, thin blood pouring through my heart'”: Trump talks health concerns, saying he takes more aspirin than recommended
By Michelle L. Price and The Associated PressJanuary 2, 2026
6 days ago
arctic
Environmentclimate
‘I opened her door and the wind caught me, and I went flying’: The U.S. Arctic air surge is sweeping northerners off their feet
By Holly Ramer and The Associated PressDecember 30, 2025
9 days ago
Tatiana
PoliticsObituary
Tatiana Schlossberg, granddaughter of JFK and cousin of Health Secretary RFK Jr., dies of cancer at 35
By Nick LichtenbergDecember 30, 2025
9 days ago

Most Popular

placeholder alt text
Law
Amazon is cutting checks to millions of customers as part of a $2.5 billion FTC settlement. Here's who qualifies and how to get paid
By Sydney LakeJanuary 6, 2026
2 days ago
placeholder alt text
Future of Work
AI layoffs are looking more and more like corporate fiction that's masking a darker reality, Oxford Economics suggests
By Nick LichtenbergJanuary 7, 2026
1 day ago
placeholder alt text
Economy
Mark Cuban on the $38 trillion national debt and the absurdity of U.S. healthcare: we wouldn't pay for potato chips like this
By Nick LichtenbergJanuary 6, 2026
2 days ago
placeholder alt text
Future of Work
'Employers are increasingly turning to degree and GPA' in hiring: Recruiters retreat from ‘talent is everywhere,’ double down on top colleges
By Jake AngeloJanuary 6, 2026
2 days ago
placeholder alt text
Success
MacKenzie Scott sends millions to nonprofit that supports anti-Israel and pro-Muslim groups, two of which are facing federal probes
By Sydney LakeJanuary 6, 2026
2 days ago
placeholder alt text
Personal Finance
Current price of silver as of Wednesday, January 7, 2026
By Joseph HostetlerJanuary 7, 2026
1 day ago

© 2025 Fortune Media IP Limited. All Rights Reserved. Use of this site constitutes acceptance of our Terms of Use and Privacy Policy | CA Notice at Collection and Privacy Notice | Do Not Sell/Share My Personal Information
FORTUNE is a trademark of Fortune Media IP Limited, registered in the U.S. and other countries. FORTUNE may receive compensation for some links to products and services on this website. Offers may be subject to change without notice.