by WASHINGTON (AP) – It’s been 12 years since a pair of conservative writers likened a leading climate scientist to a child convicted for his portrayal of global warming. Now, a jury is about to decide whether the comments were defamatory.
Closing arguments were made on Wednesday in a lawsuit brought by Michael Mann, which emerged from a graph first published in 1998 in the journal Nature dubbed the “hockey stick” as a dramatic depiction of a warming planet. Mann’s graph showed average temperatures in the Northern Hemisphere changing little for 900 years until they began to rise rapidly in the 20th century.
The work made Mann, then at Penn State but now at the University of Pennsylvania, widely exhibited. It was included in a 2001 United Nations climate panel report, and a version of it appeared in Al Gore’s Oscar-winning 2006 climate change documentary, “An Inconvenient Truth.”
It also raised suspicions — two of whom Mann took to court over attacks he said damaged his career and reputation in the United States and internationally.
In 2012, the Competitive Enterprise Institute, a libertarian think tank, published a blog post by Rand Simberg that compared investigations at Penn State University — Mann’s employer — into Mann’s work with the case of Jerry Sandusky, a former assistant football coach. who was convicted of sexually assaulting multiple children.
Mann’s research came under scrutiny after he leaked his and other scientists’ emails in 2009 in an incident known as “Climategate” that brought further scrutiny to the “hockey stick” graph, with skeptics claiming Mann manipulated data. Investigations by Penn State and others, including The Associated Press’ examination of the emails, 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 instead of molesting children, he has molested and tortured data,” wrote Simberg. Another writer, Mark Steyn, later referenced Simberg’s article in his own National Review piece, calling Mann’s research “fraudulent.”
Mann sued both men and their publishers, seeking monetary damages. The case has bounced through various courts since then. In 2021, a judge dismissed the two outlets as defendants, saying they could not be held liable, but that the claims against the individuals remained.
Both men said they were just expressing their opinion.
Steyn declined to comment while the trial was underway. Simberg, in a statement, said the case was about “the ability of myself and others to speak freely about the most important issues of our day, whether it’s climate change or something else.”
“If other people have over a decade of litigation for making their comments,” Simberg said, “we’re all going to suffer.”
Her attorney, Victoria Weatherford, argued in her closing that Simberg has the right to express his opinion. “Inflammatory is not the same as defamatory,” she said.
Mann’s attorney, John Williams, questioned in his conclusion whether Simberg and Steyn believed the allegations they made against Mann or whether they “just advanced their political agenda”. He told jurors that by awarding damages, they could “set an interest not only in punishment but in setting an example to prevent others from acting in the same way.”
Kate Cell, whose work as senior climate campaign manager at the Union of Concerned Scientists includes tracking climate disinformation, said Mann’s case is well known among other climate scientists. She said many hoped a favorable verdict for Mann would “bring comfort and regularity to those who do not accept the science of climate change and who speak very boldly about climate scientists.”
Mann had to prove that the writers not only made false and defamatory statements, but that they acted with actual malice – a higher threshold for cases involving public figures.
Lyrissa Lidsky, a professor of constitutional law at the University of Florida and an expert on defamation, said the law in defamation cases involving public figures often favors free speech rights.
“There is a misconception that defamation is just a contest of what is true and what is not true,” she said.
The trial comes as climate change continues to be a divisive and highly partisan issue in the United States. A 2023 poll by 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.
Many scientists have followed Mann’s case for years as misinformation about climate change proliferated on several social media platforms, many themselves under attack. Lidsky was skeptical that Mann’s case would have wider significance, especially on social media.
“A jury decision in one case about a climate scientist will not stop climate skeptics,” Lidsky said, “no matter what the outcome of the trial.”
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