I saw the movie when it first came out - and was traumatised. I watched it in a theatre because at the time I was writing TV reviews for the London Evening News. At the end, the audience was totally silent.
I gave it a fantastic review but the thing I really remember is the cover of the Radio Times, a listings mag, when it was broadcast on TV. It was a photo of a traffic warden, armed with an assault rifle, and with a bandaged eye, standing guard. It stuck in my mind because it summed up the complete breakdown of society in one brilliant picture.
I've always thought that movie actually saved us: it was shown in Russia without cuts, I believe. Suddenly Russians understood just how appalling a nuclear war would be and how the West was as afraid of the Soviet Union as the Soviet Union was afraid of us.
I think we need something similar for global heating.