Jack Johnson: A Greener, Cleaner Rock Star

"Honestly, I probably don't pay that much attention to it," said concertgoer Matt Bodnar.

But that won't change Johnson's message, though some believe he's preaching to the choir.

"We don't get to see the positive things or the negative things it's doing until a few years later," he said. "I think preaching to the choir is important too, to reiterate to kids that it is cool and OK and it's not geeky to think about this stuff."

"We're not gonna change the world, me or the band or our little crew, but when you take the thousands of people we play for each night and when they start taking action and everybody starts to work together it's a big growing wave and everybody does their little part so in that way music can change the world," Johnson said.