WASHINGTON (CN) - The Supreme Court said Monday it would not hear National Review's bid to overturn a Washington, D.C., court's order that allowed a Penn State climate scientist to bring a defamation lawsuit against the conservative magazine and a right-leaning think tank over blog posts that called his work fraudulent.
The case centers on Michael Mann, a professor at Penn State famous for developing the so-called "hockey stick graph" that used ice core samples, tree ring analysis and other data to show global temperatures rising dramatically in the 20th century after a general trend of cooling for most of history.
Mann's work has been instrumental in the charged debate over the threats posed by climate change, as the graph he helped develop was a key point of evidence that human activity is driving the warming of the planet.
The graph has been the subject of hot debate and some climate skeptics have called into question its validity, though peer-reviewed studies have largely backed up Mann's findings.
The criticisms became particularly acute after the so-called "Climategate" scandal, in which a tranche of emails from climate scientists were hacked and publicly released. Climate skeptics used some of the emails to claim Mann and his team manipulated data and created a misleading graph, a claim Mann says comes from a deliberate misreading of emails.
Nevertheless, the controversy led Penn State, the Environmental Protection Agency, the British House of Commons and others to launch investigations into Mann's work that cleared Mann and his team of wrongdoing.
But the investigations left some critics of Mann cold, namely Rand Simberg of the right-leaning Competitive Enterprise Institute and columnist Mark Steyn.
Simberg penned a post in July 2012 on a CEI blog that compared Penn State's investigation into Mann to the school's handling of the scandal involving convicted pedophile Jerry Sandusky, a former Penn State football coach.
"Mann could be said to be the Jerry Sandusky of climate science, except for instead of molesting children, he has molested and tortured data in the service of politicized science that could have dire economic consequences for the nation and planet," Simberg wrote.
CEI has since removed the comparison from the post, calling it and another sentence "inappropriate."
In a post days later on a National Review blog, Steyn took up Simberg's arguments, quoting largely from the piece. Though Steyn demurred on the Sandusky comparison, he did refer to the hockey stick graph as "fraudulent" and questioned the rigor of the university's investigation.
Mann sued for defamation in Washington, D.C., Superior Court, and National Review, Steyn, CEI and Simberg quickly moved to dismiss under Washington's anti-SLAPP law, which allows for the dismissal of lawsuits that aim to silence critical speech about "issues of public interest."
The court denied the motions and allowed the case to go forward. The D.C. Court of Appeals eventually upheld the lower court's ruling, finding a jury could reasonably find the posts included false statements accusing Mann of misconduct.
National Review and CEI have called the decision a threat to the First Amendment that conflicts with a lower court "consensus."
"Everything from speculation about the president's actions and intentions concerning the special counsel investigation to questioning government officials' motivations in taking actions that disproportionately affect persons of particular nationalities or religious faiths is fair game for a defamation lawsuit under the court of appeals' logic," CEI's brief urging the court to take up the case stated.
The Supreme Court declined to hear the appeal on Monday, though Justice Samuel Alito dissented from the decision in an eight-page opinion.
"The petition in this case presents questions that go to the very heart of the constitutional guarantee of freedom of speech and freedom of the press: the protection afforded to journalists and others who use harsh language in criticizing opposing advocacy on one of the most important public issues of the day," Alito wrote. "If the court is serious about protecting freedom of expression, we should grant review."
Sam Kazman, CEI's general counsel, praised Alito's dissent and said the group will fight Mann's claims in court.
"We are disappointed by the Supreme Court's rejection of CEI and National Review's First Amendment cert petition, but we are nonetheless confident that we will prevail in trial court, where these cases will now proceed," Kazman said.
Read the Top 8
Sign up for the Top 8, a roundup of the day's top stories delivered directly to your inbox Monday through Friday.