He was very much a proto-Greenie. I believe he even got rid of his car because he disliked the damage they were doing. There's reams and reams about this topic out there, but I'm afraid it's not one of the big themes that gets picked up on about Tolkien these days, strangely
Maybe Al Gore could make use of Tolkien in selling his film to the young 'uns?
Interestingly, when the BBC did the Big Read to find the UK's favourite book, each was championed by a famous person. Lord of the Rings, which won, was championed by Ray Mears, well known in the UK for being a keen outdoorsman and environmentalist, and one of the things he loved most about Tolkien was his love for the unspoiled natural world.