Every generation gets the apocalypse it deserves; when it comes to its realisation in the arts, that is. Back in the eighties when I was tramping the streets beneath a banner made of broom handles and a sheet, it was nuclear war that had us on the edge of our seats. You'll be pleased to know the demonstrations were successful and nuclear war never happened.
Environmental apocalypse is the disaster movie du jour, although cinematic license is required; a slow-warming or cooling world not having the impact on screen atom bombs have. As a consequence, recent efforts have either had to accelerate the science or keep matters vague, 'The Road' pursuing the latter strategy in book - written by Cormac McCarthy - and on screen. You know that something bad has happened - everything and almost everyone is dead, trees are dead in the earth, conflagrations are spontaneous and the horizon wreathed with smoke - you're just not quite sure what exactly. Whatever it was, it's left a landscape so devastated it could only be filmed in Pittsburgh and New Orleans in a palette of ash greys, char blacks and dirt browns.