Climate scientists in particular have borne the brunt of those who feel threatened by reality. Michael Mann in particular has borne the brunt of many of these attacks, as he produced some iconic research the "hockey stick" which has clearly illustrated the unusual nature of recent warming.
He's had to put up with people claiming his research was fraudulent for a long time, despite it being independently replicated by many others (see diagram above). Well, he's finally striking back, yet another correspondent has publicly accused him of doing fraudulent research in print.
Now, the "Hockey Stick" is not fraudulent. This discussion of the "Hockey Stick" goes into much better detail about it (actually, it gets a bit technical), but the take home message is that the results are well validated, reproducible in other studies and most importantly, the statistical treatment (it wasn't a "mathematical formula as most lay people would understand) did not automatically generate "hockey sticks" (It was principle component analysis for crying out loud). See also this discussion of "Hockey Stick" myths.
Anyway, he has, through his lawyers, issued a letter asking for removal of the article and a public apology. Good on you Michael, let's hope you get the apology.
If you are interested in helping climate scientists defend themselves for the numerous attacks on them, you might consider contributing to the Climate Science Legal Defence Fund.