I've just been to a colleague's lecture on Secular and Religious Forms of the Apocalypse in Popular Culture. Two hours really isn't enough on this stuff, but it was a thrilling ride. His major point was that religious Apocalypses have a purpose, whereas secular ones don't.
More specifically, 'apocalypse' literally means 'revelation': the point isn't necessarily the destruction, it's the epiphany the individual has which qualifies them to be Saved. Dispensationalism holds that a final destruction has to happen before the eternal Reign of Heaven can be instituted. It separates the sheep from the goats, in which the 'wrong' Christians, Jews who won't convert, atheists and adherents of all other religions get what's coming to them. All the suffering has a purpose. For example The Left Behind series of books, films, games and comics, for example, explains that only the best Christians go to heaven immediately (the first one opens with airline pilot Rayford Steele (a porn name if ever I saw one) realising that his missing passengers must be the True Believers who've been given a first class ticket to heaven, and that he and his allies must Shape Up Or Be Damned (continued over 12 volumes). The remaining weak Christians have to battle the Anti-Christ (he's the head of the United Nation, naturally) to demonstrate their righteousness.
The problem for popular representations is that people getting to heaven by being nice is very boring, and in any case, the dispensationalists (the theological term for Rapture-ready Christians) don't really believe in niceness as the route to heaven. They aren't Quakers or Oxfam: they actually want to bring on the Apocalypse because it's God's plan, and you get saved by converting and/or killing as many unbelievers as possible. You should want the Apocalypse - which is why American evangelicals are so heartily opposed to environmentalism: God gave the earth to be used, not conserved (this is the theme of that Protestant Ur-Text Robinson Crusoe and interfering with global warming is like mooning at Jesus. Anyway, killing infidels makes for more exciting viewing than Good Works, but runs the risk of attracting those who just enjoy the slaughter. And there are a lot more of them than you'd think: Left Behind has sold upwards of 60m copies.
You can check whether the Rapture is near on Raptureready.com, which collates evidence on a minute-by-minute basis. Seriously. Baroness Warsi's there now, adding the wave of sarcasm I and others directed at her as evidence of Satan's rise. Currently - and I'm not kidding - they're claiming that the Satanic background to the Eagles' Hotel California, combined with the US government's increase in passport fees, signals that we are 'nearing midnight'. Personally I'd have thought that the continued toleration of the Eagles' soft rock is in itself a sign that we're living in hell already, but I'm no theologian. But they have a kind of consolation: God has a plan and will make it alright, at least for the chosen few.
Steve's converse point is that secular apocalypses don't have end-points or purposes. Up to a point, I think. There are plenty which use the end of the world as a background for explorations of familiar themes, such as masculinity or individualism: Mad Max is a thinly disguised Western for example. Others engage with politics, or the nature of human society, such as the unrelentingly grim, unsensationalist The War Game (made by the BBC and then banned - I saw it in an old nuclear bunker and it scared the bejasus out of me). Still more reflect popular anxiety about globalisation (Contagion), environmental collapse or technophobia (Terminator). They don't have an Ultimate Purpose, but they function as Jeremiads: warnings. They tell us that we are fully capable of destroying ourselves because we lack maturity as a species - like this:
There's also the erotic self-harming element: flogging ourselves with the thought that, having been stupid enough to destroy ourselves once, we'll recover just enough to do it all over again - such as in the curious Catholic novel A Canticle for Leibowitz, in the knowledge that we probably won't:
In literature, non-vampire teen fiction (and also adult literature), once concerned with nuclear holocaust (Z for Zachariah, Brother in the Land), is obsessed with environmental collapse - my shelves are groaning with dead trees stamped with stories about, well, dead trees (and everything else). Science fiction, remember, is never about the future: it's about the fears of the society in which it was written. Bertagna's Exodus, Blood Red Road, The Testament of Jessie Lamb, Ready Player One, The Wind-Up Girl, Ship Breaker, Momentum, The Hunger Games to some extent, Jensen's eco-thriller The Rapture, a lot of Philip Reeve's work, Baxter's Flood, Sedgwick's Floodland… and that's just a small selection. Kids who read must be terrified! I guess that, like all the nuclear fiction of earlier generations, children's apocalypse fiction (and fiction featuring kids, like The Road) is given extra weight by the implied readers' impotence: they're innocent, and adults are doing these horrendous things to us: it's a kind of pornographic fantasy.
So religious apocalyptic culture is in a way smugly optimistic: it's the cleansing before heaven (for some), whereas secular apocalypses function both as warnings about self-harm, and as weirdly comforting fantasy.
What's the answer? Well, Kurt Vonnegut's Galapagos depicts a humanity which is finally safe and happy… because we evolved to be seal-like creatures incapable of doing too much damage. Someone throw me a fish.