[Andols]

I was trying to think of as many ELE concepts as I could yesterday and was amazed that I've only come across a handful. Outside the usual asteroid/solar flare/alien laser has anyone come across anything different?

[Jennifer P]

Nanotech out of control and turning the world into grey goop - Alastair Reynolds' Century Rain

A bacteria that ignites all the oil-based fuels - I *believe* that is the civilization-ending event in Scott Westerfeld's Uglies, but I could be wrong.

Alien nanotech dismantles the Earth to build starships - Greg Bear, Moonseed

Weather control causes climate collapse - Robert Silverberg, Nightwings

And if we're going to go old school, let's not forget Orbital weapons discharge renders most of the population blind AND killer plants attack - that being, obviously, the 1950s classic 'Day of the Triffids' by John Christopher. He also wrote two other post apocalytic novels, 'The Chrysalids' (nuclear war) and more interestingly 'The Death of Grass' (virus renders every species of grass extinct).

(If I'm misremembering any authors/books, PLEASE correct me. And some of these are 'civilization ending' not 'world ending'. I've also avoided standard human plagues because they seem to be 'the usual')

[Fung Koo]

I think you mean John Wyndham, feller ;)

There was a thread about this in the Writing forum a little while ago.

There's your unavoidable impact with: supernova, asteroids, galaxies, rogue planets/systems, wandering interstellar lethal gas clouds, high velocity purpose-built highway-making projectiles.

There's your near-impact-with-X-that-has-severe-implications: large object dragging us out of orbit, large object/gas cloud obscuring the sun, etc.

There's your self-extermination varieties: nuclear, biological, chemical.

There's your independence-day scenario: alien invasion/extermination/speculation (in more ways than one! :D).

Then there's your somewhat less concrete ones: temporal incursion/paradox, the sun "hiccoughs" into a higher or lower energy state, spatial expansion ripping everything apart/spatial compression forcing everything into goop, some fundamental change in the laws of universe screwing everything up, etc.

Then there's the Act of God variety.

And that's pretty much most of em.

[JunkMonkey]

Not a novel but the Babylon 5 spin-off TV show Crucade was based on the premise that aliens had seeded Earth with a engineered plague that would destroy all life (when it finally got round to adapting to host conditions - bit of a dodgy super-weapon that takes five years to go off, but what the hell. It would have been a short series if it had worked straight out of the can.)

To add to Fung's exhaustive list, there's also the Going Back in Time and Stomping on Butterflies scenario.

[manephelien]

One of the more unique scenarios is Arthur C. Clarke's Childhood's End (aliens help the children of humanity ascend to a higher plane of existence, destroying the Earth in the process).

[Andols]

childhoods end was a good one. wasn't there a short story about all the water instantly turning to ice?

[JunkMonkey]

Ice Nine by Kurt Vonnegut?

[Jennifer P]

Fung is, of course, right. See, I said I'd get somebody wrong :P

A couple more I thought of.

Alastair Reynolds' work has an entire series of books where a highly advanced civilization gets destroyed by a computer virus/nanotech virus.

And although in this case the apocalypse does not fully happen, terraforming gone wrong is the threat in Roger MacBride Allen's trilogy that starts, I think, with The Ocean of Years (the other two are The Shores of Tomorrow and The Depths of Time)

And in C.J. Cherryh's Hammerfall series a warring race decides it would be tactically sound to terraform an inhabited planet.

[Bond]

The Hitchhiker's Guide to the Galaxy: Aliens destroy the world to make way for an interstellar freeway
The Time Machine: Moon mining results in it splintering
The Last Question: Entropy and reboot

[JunkMonkey]

In William Tenn's short story the Liberation of Earth the world is all but destroyed (at least rendered pear shaped) by a constantly being liberated, re-liberated and re-reliberated by the combatants in an interstellar war.