Indeed he is and this new Movie of his shows how, like Gates and Buffett and so many others, rich doesn’t immunize from stupid about politics or science.
In fact being rich means you never have to deal with being wrong, so you don’t learn the scientific methods necessary to finding the truth.
Cameron thinks it is, therefore it is–the science is settled.
Lubos Motl writes a great little take down.
http://motls.blogspot.com/2014/04/years-of-living-dangerously.html
I don’t think Cameron would waste his time being an “environmentalist” unless he was being payed to be involved.