In a nutshell, some right wingers wrote some insulting things about climatologist Michael Mann. According to the contribution, these things included the phrase "academic and scientific misconduct" and three more.
Now if Dr. Mann did engage in misconduct, that might not be libelous, but if he did not, then broadcasting those phrases about a private professional would be libelous.
Burrus tries to hide behind the smokescreen that it's all a part of the climate change debate.
No, it's libel.
Science isn't done by blog or by National Review Online.
(P.S. Burris is associated with the Koch-funded, science denying Crapo (Cato) Institute)