This is fascinating. I think it's important that we discuss this - people in general want the best for themselves and others, but don't believe others want that. We could do with being a little less cynical about our fellow people, I think!
This finding of "hidden" public support for green policies strongly echoes our work on pluralistic ignorance when it comes to non-car travel: most people support non-car travel more than car travel, but at the same time they believe this is a minority view