Back in 2012, after the Competitive Enterprise Institute and the National Review each published pieces that likened climate scientist Michael E. Mann to a child molester and called his work a fraud, Mann fought back with a lawsuit, charging them with libel. Now, in a preliminary ruling, a Superior Court Judge has sided with Mann, paving the way for the case to move forward and potentially setting an important precedent about the limits of disinformation.

The ruling, in essence, reinforces the wise adage attributed to former New York Sen. Patrick Moynihan that, while everyone is entitled to his or her own opinion, we are not each entitled to our own facts. But first, some background.

Hockey Stick, Lightning Rod

Michael Mann, a world-renowned climate scientist at Penn State University, is perhaps best known as the author of the so-called "Hockey Stick" graph. Some 15 years ago, in 1999, Mann and two colleagues published data they had compiled from tree rings, coral growth bands and ice cores, as well as more recent temperature measurements, to chart 1,000 years' worth of climate data. The resulting graph of their findings showed relatively stable global temperatures followed by a steep warming trend beginning in the 1900s. One of Mann's colleagues gave it the nickname because the graph looks something like a hockey stick lying on its side with the upturned blade representing the sharp, comparatively recent temperature increase. It quickly became one of the most famous, easy-to-grasp representations of the reality of global warming.

The United Nations' Intergovernmental Panel on Climate Change featured Mann's work, among similar studies, in their pathbreaking 2001 report, concluding that temperature increases in the 20th century were likely to have been "the largest of any century during the past 1,000 years." But while Mann's peer-reviewed research pointed clearly to a human role in global warming, it also made Mann a lightning rod for attacks from those, including many in the fossil fuel industry, who sought to deny the reality of global warming.

Years of Attacks

In the many years since Mann published the Hockey Stick graph, his research has been subject to an extraordinary amount of scrutiny. Despite the fact that the U.S. National Research Council endorsed Mann's "hockey stick" findings in 2006 and subsequent research has substantiated them further, Mann has still faced a steady stream of personal attacks on his credibility, death threats, and even a simulated anthrax attack.

Many of the attacks Mann faced are chronicled in his recent book-length account, The Hockey Stick and the Climate Wars. Among these, in 2009, scientists' emails were hacked -- including Mann's -- and a trumped-up controversy ensued. Mann's employer, Pennsylvania State University, along with multiple governmental committees, upheld his research and conduct. Still, former Virginia Attorney General Ken Cuccinelli, another climate contrarian, sued the University of Virginia, Mann's former employer, to gain access to his private emails. After the Union of Concerned Scientists organized a letter from Virginia academics protesting the investigation, the university stood up to Cuccinelli in court and won. Another demand for his emails - this time from a group called the American Tradition Institute -- is still working its way through the courts.

When Disinformation Crosses the Line

Against this charged backdrop, Mann's libel case stems from two particular articles that appeared in 2012. At the time, news had recently surfaced that officials at Penn State University had ignored or concealed evidence that former assistant football coach Jerry Sandusky had allegedly molested children. That July, Rand Simberg, an adjunct scholar at the Competitive Enterprise Institute (CEI), wrote a post for the organization's blog likening Mann's work to the Sandusky case. Simberg called Mann "the Jerry Sandusky of climate science, except that instead of molesting children, he has molested and tortured data."

Several days later, CEI deleted the passage, acknowledging that its publication was "inappropriate." But Mark Steyn, a long-time contributor to the National Review magazine, quoted Simberg's comments on the magazine's blog. Steyn said that, while he might not have made the comparison, "Mr. Simberg does [have] a point. Michael Mann was the man behind the fraudulent climate-change 'hockey-stick' graph."

A Ruling that Matters

The recent preliminary ruling in Mann's libel case is blunt and clear. It is also surprising: In rejecting the motion to dismiss the case and opening the way for a trial, Washington, D.C., Superior Court Judge Frederick Weisberg gave the defendants something of a pass for likening Mann to child molester, noting that, "opinions and rhetorical hyperbole are protected speech under the First Amendment."

Erroneously and publicly accusing a scientist of fraud is another matter, the judge ruled however. As he put it:

"Accusing a scientist of conducting his research fraudulently, manipulating his data to achieve a predetermined or political outcome, or purposefully distorting the scientific truth are factual allegations. They go to the heart of scientific integrity. They can be proven true or false. If false, they are defamatory. If made with actual malice, they are actionable."

Protecting Speech, Protecting Science

The distinction in the ruling is an important one. As a journalist who has written about the intersection of science and politics for three decades, I am a staunch defender of free speech. But libel is a special case. In the United States, the bar is set high -- as it should be. A writer or publication can only be found guilty of libel if they knowingly publish false information that damages someone's reputation.

There's little question that Mann's public reputation has been damaged by the many spurious attacks against him. But the problem in this case is bigger than claims about one man's maligned reputation. Attacks against Mann, after all, are mostly intended to further confuse the public about the importance of Mann's scientific contribution to our understanding of global warming. Other scientists have faced similar legal attacks and a new Climate Science Legal Defense Fund is helping them respond.

What makes this case so important is that science, like free speech, needs protecting too. Sadly, we have been living in a period during which many parties -- often with funding from the fossil fuel industry -- have knowingly spread disinformation about climate change. They have sown confusion about scientific facts and damaged our discourse on the topic just as they have -- in the personal smears Mann has endured -- arguably harmed his reputation. In so doing, there is no question that this disinformation has been used to knowingly and seriously erode the public's understanding of an issue with immense consequences for our future.

While the ultimate outcome of Mann's case remains unclear, Mann's attorney, John B. Williams, not surprisingly says he is pleased with the ruling. "We're ready for the discovery phase of the case," he says, adding that he and his client have already compiled a request for much of the correspondence between the various parties in the lawsuit, including emails, etc., to try to establish that they knowingly published false information about Mann or otherwise proceeded with "reckless disregard" for the truth about Mann's scientific work.

Mann declined to comment directly about the case, but was happy to speak about the broader issue involved. "There is a good faith debate to be had about the policy solutions to combat human-caused climate change," he says. "But we can no longer continue the unworthy, fake debate about whether the problem exists. Scientists have a key role in informing that discussion. We cannot afford to sit on the sidelines any longer."

Seth Shulman, Senior Staff Writer at the Union of Concerned Scientists, is a veteran science journalist and author of six books whose work has appeared in The Atlantic, Discover, Nature, Technology Review, Parade and many other publications. You can sign up to receive his monthly Got Science? column via email at the Union of Concerned Scientists website: www.ucsusa.org.