And by "terrorism", he means "exposing scientific fraud"

Your Dot: On Science and ‘Cyber-Terrorism’ - Dispatch from the Bizarro World of Climate Fraud Promoter Raymond T. Pierrehumbert of RealClimate - Dot Earth Blog - NYTimes.com

...I found the general lack of indignation in your piece rather disconcerting. After all, this is a criminal act of vandalism and of harassment of a group of scientists that are only going about their business doing science. It represents a whole new escalation in the war on climate scientists who are only trying to get at the truth. Think — this was a very concerted and sophisticated hacker attack.
...
...this illegal act of cyber-terrorism against a climate scientist (and I don’t think that’s too strong a word) is ominous and frightening. What next? Deliberate monkeying with data on servers? Insertion of bugs into climate models? Or at the next level, since the forces of darkness have moved to illegal operations, will we all have to get bodyguards to do climate science?

Maybe reporters just like information to be out, even if it is illegally obtained. Certainly, I thought it was right to publish the Pentagon Papers. But when the attack is on an individual scientist rather than a government entity, and when the perpetrator is unknown and part of some shadowy anonymous network, it raises a lot of new concerns.

The real story here, though, is that the tactics the inactivists have been using in the run-up to Copenhagen have been all outside the sphere of legitimate scientific discourse. Bogus petitions, sham attempts to gut the A.P.S. climate statement, and now cowardly illegal outings of private emails from an individual scientist. If this is what they have to stoop to, then it is clear that they must really not think they have a leg to stand on scientifically.