Chomsky's reply was spot-on, and applies to climate change even more than it does to 9/11:
During a "Policy and the Media Prism" lecture at the University of Florida several weeks ago, 9/11 truther activist Bob Tuskin asked Chomsky what he had to say about Building 7, the third structure to collapse on Sept. 11, 2001. The media, in Tuskin's opinion, has ignored evidence about the building's collapse.
Chomsky shut down Tuskin's claims. If scientists had strong evidence to support 9/11 conspiracy theories, he said, they would have presented their discoveries to other architects and engineers, would have published their arguments in scientific journals and attempted to persuade other professionals that they'd found something worth investigating.
"There happen to be a lot of people around who spent an hour on the Internet and think they know a lot of physics," he added, "but it doesn't work like that ... There's a reason there are graduate schools in these departments."