"An Inconvenient truth", Al Gore's movie on the future of the planet

I already had the chance to see Al Gore's speech twice, in Davos and TED, and I was shocked each time. Here is the long awaited movie trailer "of the most terrifying film you will ever see". I like it, it's impressive, surprising and frightening, as Al Gore's speech is. However I was surprised when I showed it to my 10 years old son he said "oh, this can only happen in movies right ?". That may be the only drawback of having chosen cinema as a medium for this message, most people will probably think it is fiction while we can't be more in reality.