I think most, if not all people know or have zero doubts that global warming exists. Maybe if you didn't ever go to school, read a book or watched tv you may not realise that the world's climate has warmed and cooled over its history. My guess is that even 8 year olds who have watched the movie "Ice age" probably realise we are not in an ice-age now and put 2 and 2 together.
As far as an energy policy is concerned, it is pretty simple. Nuclear is the cleanest, cheapest and most reliable way to go.