Wind turbines on the Cedar Creek wind farm near Grover, Colo
Wind turbines on the Cedar Creek wind farm near Grover, Colo., in 2009. At a hearing next week in Washington, D. C., lawyers will argue whether a lawsuit engendered by an academic dispute over renewable energy research is intended to suppress free speech and therefore should be dismissed by the court. Credit: Carlye Calvin/UCAR, CC-BY-NC 2.0

After a leading U.S. scientific journal published a paper that claimed that Mark Z. Jacobson’s research on renewable energy was flawed, the Stanford University climate scientist sued the journal and the paper’s lead author for defamation. That lead author, Christopher Clack, CEO of Vibrant Clean Energy in Boulder, Colo., and the journal—Proceedings of the National Academy of Sciences of the United States of America (PNAS)—now are asking that the suit be thrown out.

The defendants, Clack and PNAS, say that the suit’s true aim is to suppress free speech and scientific debate. If that argument prevails, said Los Angeles attorney Kenneth White (who is not involved in the case but has litigated numerous First Amendment cases), it will indicate that suits like Jacobson’s can be successfully defended under “anti-SLAPP” laws, statutes intended to prevent people from using litigation as a tactic to intimidate and silence critics. A hearing on the motion to dismiss the lawsuit is scheduled for 20 February in the Superior Court of the District of Columbia.

Anti-SLAPP laws—the acronym stands for strategic lawsuit against public participation—allow defendants to argue that a lawsuit should be dismissed on the basis that it’s intended to suppress their free speech.

Anti-SLAPP laws—the acronym stands for strategic lawsuit against public participation—allow defendants to argue that a lawsuit should be dismissed on the basis that it’s intended to suppress their free speech. That avoids, or at least postpones, the more expensive process of discovery involved in arguing the substance of the claims themselves. “It takes away the litigation terrorism approach, where we’re just going to cost you tons of money by suing you,” said White, who writes about First Amendment issues at the blog Popehat. “Hopefully it will be [thrown out], and that will represent an early victory; it means this kind of thing can be fought back successfully.”

Attorney Paul Thaler, who is representing Jacobson in the case, told Eos that characterizing the lawsuit as an attack on scientific debate misrepresents the complaint. The suit isn’t asking a judge to determine which scientific argument is correct, he explained, but rather, whether Clack and PNAS lied in a way that damaged Jacobson’s reputation.

“We’re not litigating science, we’re litigating defamation claims,” he said. “To cloak it in science and say, ‘We’re protected because we’re talking about science,’ in our opinion, is not enough. You can’t lie about someone in the context of science, just like you can’t lie about someone in other fields.”

Mark Z. Jacobson in 2006
Mark Z. Jacobson in 2006. Credit: Linda A. Cicero/Stanford News Service

High Stakes

The events leading to this extraordinary legal case began with a paper that Jacobson and three colleagues published in PNAS in December 2015. Their article asserted that a low-cost electrical grid based on 100% wind, water, and solar power was possible. Clack, then with the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory in Boulder, Colo., and 20 coauthors responded with a June 2017 article, also in PNAS, that laid out an exhaustive point-by-point critique of Jacobson and his colleagues’ work.

The following September, Jacobson sued PNAS and Clack, alleging that Clack defamed him by misrepresenting some of the data Jacobson reported in his paper and by claiming that Jacobson’s research contained modeling errors. (Defamation refers to damaging someone’s reputation by making false statements.) Major media outlets, including the New York Times, Scientific American, and Forbes, have reported on the dispute.

Jacobson asserts in court documents that he raised his concerns with PNAS editors in numerous emails over several months but that they refused his requests to retract the Clack paper or correct its errors. (PNAS published his response in the same issue.) His suit asks for the Clack paper to be retracted in full, along with $10 million in damages.

Jacobson’s original paper was frequently cited by presidential candidate Bernie Sanders and other clean-energy advocates.

That eye-popping amount, along with the high-profile and political nature of the research—Jacobson’s original paper was frequently cited by presidential candidate Bernie Sanders and other clean-energy advocates—is part of the reason that the suit has garnered so much attention.

“I don’t take (the number) seriously or literally,” White said. It’s just a big number to scare people, he said. The amount of damages illustrates how important anti-SLAPP laws are, he added. Such laws provide “the only way you can really put on a full First Amendment defense early on, and only a handful of states have decent ones,” White said.

A Legal Outlier

Attorneys said Jacobson’s lawsuit is unusual. Scientists may file lawsuits if, say, they lose funding or get fired over what they believe are false accusations of fraud or misconduct, but it’s usually a last resort, said Callan Stein, a Boston, Mass., attorney who is not involved with this case but has represented scientists accused of misconduct.

“I’ve never heard of a case like this before,” he said. “If someone publishes an article that they know is false that specifically targets a scientist in a defamatory way,” that’s very different from a good-faith difference of opinion or a different interpretation of data, noted Stein. “That’s what Dr. Jacobson is alleging here.”

Christopher Clack
Christopher Clack. Credit: CIRES/NOAA

On the basis of his observations and experience, although he didn’t have hard evidence, Stein ventured that litigation involving scientists is on the rise. He attributes this to the growth of online review sites, which make it easier for scientists to publicly comment on and critique each other’s research. He noted a cancer researcher’s 2014 defamation suit against anonymous commenters on the website PubPeer, which is still in litigation, as one high-profile example of a scientist taking legal action.

“You have more researchers scrutinizing work, more researchers commenting, often anonymously,” Stein said. “You have more overall allegations of misconduct, more scientists in the crosshairs, more people who feel they’ve been wrongly accused.”

In the case of the Jacobson lawsuit, however, both of the clashing articles went through all the steps of the scientific review process, White noted. “Suing over peer-reviewed articles that are disagreeing with your peer-reviewed article is quite unusual,” he said.

Spurred to Action

Stein said that after looking at some of the media coverage of the dueling papers, he felt like he understood why Jacobson may have decided to take his dispute to court. At least 12 media outlets ran articles about the scientific clash. Jacobson’s complaint notes that the Forbes article ran under the headline “Debunking the Unscientific Fantasy of 100 Percent Renewables.”

“I understand why this spurred him to such a drastic action because, really, his integrity as a scientist was impugned by [Clack et al.’s PNAS] article, and by the media reaction to it,” Stein said. “The stakes were really high for Dr. Jacobson in a way they’re often not for other researchers.”

Eos reached out to Jacobson for comment, but Thaler said his client was not available to discuss the case. Clack’s attorney, Drew Marrocco, said that neither he nor his client would comment. The National Academy of Sciences does not discuss pending litigation, according to Jennifer Walsh, director of media relations for the National Academies of Sciences, Engineering, and Medicine.

One of the journals published by the American Geophysical Union (AGU), which also publishes Eos, and Eos itself have included articles about Jacobson’s work. In October 2017, AGU’s Earth’s Future published a paper by Jacobson making arguments similar to those in his December 2015 PNAS paper for the feasibility of an affordable, all-renewable power grid. Eos subsequently published a Research Spotlight summarizing the paper.

Court of Public Opinion

Whether or not Jacobson wins in the courtroom following the scheduled 20 February hearing and beyond, Stein noted that pursuing a legal battle “can certainly backfire.”

The lawsuit has already led to widespread criticism of Jacobson in the scientific community, he noted. Moreover, Jacobson will find that the legal process “airs all of his and Dr. Clack’s dirty laundry,” Stein added. Worse, “if you lose, you double down on the publicity hit you’ve taken.”

Thaler, however, said that going to court made sense. “I don’t think…when all is said and done that he will come out of this in worse shape,” he said. “The way we look at it, he’s protecting his science and his reputation. You almost don’t have a choice if someone is attacking you in that sense.”

“The way we look at it, he’s protecting his science and his reputation. You almost don’t have a choice if someone is attacking you in that sense,” said Paul Thaler, the plaintiff’s lawyer.

Rather than attempting to silence scientific debate, the lawsuit seeks to correct the record, Thaler asserted. “We’re not trying to impact anyone’s ability to speak,” he said. The fact that Jacobson’s critics have been vocal in arguing their case in both the scientific literature and the mainstream press shows that far from silencing or censoring them, the suit has led to more discussion and debate.

“We can still have a scientific debate,” Thaler said. “But you need to have a level playing field, and you can’t give yourself an unfair advantage by making false statements.”

—Ilima Loomis (email:, Freelance Journalist


Loomis, I. (2018), Scientific row over renewables leads to free speech legal fight, Eos, 99, Published on 15 February 2018.

Text © 2018. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.