It's not often you can actually say "case closed", but in this case it's literally true: climatologist Michael Mann has been cleared of all wrongdoing by the Inspector General of the National Science Foundation. Did I say "has been cleared"? I meant has been cleared once again, since there have been several investigations into his research and Dr. Mann has been cleared of all charges every single time (like here and here). All of this stemmed from the "ClimateGate" nonsense of the past couple of years, where leaked emails were taken hugely out of context by the press and climate change deniers, and used to smear scientists. Dr. Mann was at the center of the whole manufactured controversy, being the biggest target of the people who want to deny the Earth is warming up. This latest, and hopefully last, investigation into Dr. Mann's research (PDF) again shows he is not guilty of misconduct. A couple of the report conclusions are worth pointing out:

We found no basis to conclude that the [Climategate] emails were evidence of research misconduct or that they pointed to such evidence.

That's clear enough, I think. They also said:

Related posts: - The global warming emails non-event - Global warming emails followup - Exclusive: Michael Mann responds to Rep. Barton - New study clinches it: the Earth is warming up