Yeah, it's definitely a combination of things, because conceptually there isn't a TON that's entirely new. We've had defenders of the environment forever. My Aunt had a little store in our tiny home town of Belleville, Ontario called EcoMart in the early 90s, that ultimately didn't work out because she was so far ahead of her time.
I am kind of inclined to agree with Lola though...the old political adage, "It's the economy stupid." When it's actually inconvenient (pun intended, ha) not to be more conscious, behaviors start to change and people more actively seek solutions.