US climate scientist’s defamation case over online attacks finally comes to trial

by Dharna Noor at

A lawsuit first instituted over 10 years ago, brought by an esteemed climate scientist over alleged defamation by a rightwing blogger and an analyst, goes to trial this week.

The 2012 court case was brought by the University of Pennsylvania earth and environmental scientist Michael Mann, who is alleging that online attacks on his work amount to defamation.


The litigation targets two writers: Rand Simberg, analyst at the rightwing thinktank Competitive Enterprise Institute, who published a piece comparing Mann to a convicted serial child molester, and the National Review blogger Mark Steyn, who in a blogpost favorably quoted Simberg and called Mann’s research “fraudulent”. (Mann originally went after both publishers as well, but in 2021 a court ruled that neither the Competitive Enterprise Institute nor National Review could be held responsible for the attacks.)

The case comes amid concerns that online abuse of climate scientists has increased in recent years while misinformation about the climate crisis is also on the rise.

The attacks on Mann came as part of a wider campaign against him by a network of climate skeptics connected to the fossil fuel billionaire Charles Koch, experts have said.

The Competitive Enterprise Institute, which claims to fight “climate alarmism”, has financial ties to the Charles Koch Foundation, while the National Review regularly publishes articles dismissing climate concern science as alarmist and has also accepted Koch-linked funding.

After the renowned scientist co-published the famous “hockey stick” graph in 1998, which showed unprecedented global warming in the last century, a slew of groups in the Koch network also bombarded Mann with freedom of information requests. A Republican congressman, who was backed by a Pac established by Koch, also served him with a subpoena.