Since in class X, we could still possibly survive off-world but still within the solar system, I'd add class X+1.

X+1: Solar Elimination. Sun goes nova or has an encounter with a rogue body sufficently massive to really mess things up for the whole system of planets.

All the best!

Useful!

Where would Herbet's "The White Plague" where human females are targetted for extinction fit in this list?

In theory, we could use cloning for human continuance.

This 02007 schema is pretty much rocking my "Mad Max" world of leather-clad warriors, feral kids, and armed fashion models.

http://www.geocities.com/Hollywood/4953/kt_ros.html#pass

Pan-Galactic Three-Day Pass

by Kilgore Trout (as told by Kurt Vonnegut)

It was an exciting story, all about a man who was serving on a sort of Space-Age Lewis and Clark expedition. The hero's name was Sergeant Raymond Boyle.

The expedition had reached what appeared to be the absolute and final rim of the universe. There didn't seem to be anything beyond the solar system they were in, and they were setting up equipment to sense the faintest signals that might be coming from the slightest anything in all that black velvet nothing out there.

Sergeant Boyle was an Earthling. He was the only Earthling on the expedition. In fact, he was the only creature from the Milky Way. The other members were from all over the place. The expedition was a joint effort supported by about two hundred galaxies. Boyle wasn't a technician. He was an English teacher. The thing was that Earth was the only place in the whole known universe where language was used. It was a unique Earthling invention. Everybody else used mental telepathy, so Earthlings could get pretty good jobs as language teachers just about anywhere they went.

The reason creatures wanted to use language instead of mental telepathy was that they found out they could get so much more done with language. Language made them so much more active. Mental telepathy, with everybody constantly telling everybody everything, produced a sort of generalized indifference to all information. But language, with its slow, narrow meanings, made it possible to think about one thing at a time--to start thinking in terms of projects.

Boyle was called out of his English class, was told to report at once to the commanding officer of the expedition. He couldn't imagine what it was all about. He went into the C.O.'s office, saluted the old man. Actually the C.O. didn't look anything like an old man. He was from the planet Tralfamadore, and was about as tall as an Earthling beer can. Actually, he didn't look like a beercan, either. He looked like a little plumber's friend.

He wasn't alone. The chaplain of the expedition was there, too. The padre was from the planet Glinko-X-3. He was an enormous sort of Portuguese man-o'-war, in a tank of sulfuric acid on wheels. The chaplain looked grave. Something awful had happened.

The chaplain told Boyle to be brave, and then the C.O. said there was very bad news from home. The C.O. said there had been a death back home, that Boyle was being given an emergency three-day pass, that he should get ready to leave right away.

"Is it--is it--Mom?" said Boyle, fighting back the tears. "Is it Pop? Is it Nancy?" Nancy was the girl next door. "Is it Gramps?"

"Son--" said the C.O., "brace yourself. I hate to tell you this: It isn't who has died. It's what has died."

"What's died?"

"What's died, my boy, is the Milky Way."

X+1 leads us to X+2 -- destruction of the entire universe, for example due to the collapse of the vacuum into a "true vacuum" at a lower energy level, or some other phase change in the nature of space itself. Or, if our universe is a "brane" embedded in a higher-dimensional space, the collision of our brane with another (if that would even do anything... I'm not up on brane cosmology).

Can we even imagine X+3 -- say, the destruction of the higher-dimensional space in which all the branes are embedded?

You know, when I was in grad school during a memorable lunch break my colleagues individually confessed to brainstorming the different colloquial expressions for "vomit." They then proceeded to have a good hour-long conversation enthusiastically comparing notes on that topic.

I would extrapolate from their enjoyment that you have had a truly gleeful Holiday season!

You could also partner with someone to monetizing this: maybe a mnemonically color-coded line of collectible plush toys?

For those who read DC Comics, X+2 - X+2.5 happens roughly every 10 years.

A useful attempt at defining a notouriously difficult problem. I've been slaving away at the Wikipedia set of articles on the "End of the World" for years now - it's like herding cats, every time you think it's organized, a new article pops up with a different way of describing it. Anyway, this will be useful in the "End of Civilization" article alongside Nick Bostrom's "Typology of Risk" table.

I thought existential risk was the taint from staring into the void for too long. =} I realize its not you Jamias, but it was totally unfair coopting philosophy of existance for something as temporal as existance ending threats.

Going straight from X0: world ending to X2: universe ending is exceedingly lame heliocentric caltrop. I spit in your general direction. Not to mention totally out of genre for this taxonomy. Within some scale factors, all these apocalypse scenarios are things we could potentially avoid mitigate or reduce. If you skip from "humans re-enginerring the solar system to something unrecognizable as habitated life" to "galactic cluster erased in freak quantum physics event", you move from apocalypses we could perhaps engineer around to the domain of cosmic obliteration. that seems tragic yes, but i'm not sure if its really of the apocalyptic genre per se. Eschatology is a loaded word to a lot of people, but it seems apt in that our actions have some bearings on our fate in Jamias' taxonomy.

X+X Attack by extradimensional zombies moaning "Branes!" All universes die.

Cool list, but I disagree with the odds of ecological recovery after a global thermonuclear war. Between the fallout and the nuclear winter, the planet's going to shrouded in poison and clouds for a good long time, maybe longer than lichens and other plankton can hang on.

What about Captain Tripps? I think you really need a specific Flu Pandemic level.

Great comments, folks, thanks. Some replies:

Boinged like wow! How many views did you get from that?

Adam, most models of nuclear war project the dust settling from the upper atmosphere in less than 10 years. And not nearly enough fallout would be created to literally kill everything on the earth, only damage it severely. Hundreds of millions could die, but probably not more than half of the human species.

The New York Magazine apocalypse fever article, which has been linked to by BB before, unfortunately makes it look as if our current appraisal of the situation is biased - as if all technological catastrophic risk analysts are cuckoo. It's trendy to forecast society undergoing numerous difficulties before achieving progress, but apparently unfashionable to suggest that it might all go boom.

there is a scenario missing from it, but perhaps one which i dreamed up so that might be why:


Extinction Plus Escaping Minority: Really this is not original, it's the scenario laid out in most of the ye olde prophecies of the end of the world where the majority of humanity is wiped out and a small section of the population escapes in newly developed habitats with gravity propulsion systems delivering both energy and transportation.

Perhaps the asteroid impacts should be explicitly aligned with Torino scale 8, 9 and 10?

η

Really practical stuff!!
What the hell?

It seems to me that Class 0, Class 1, and Class 2 are useful from the point of view of human interest fiction or preparedness. The higher classes less so.

The world as we know it ends all the time. It's only a matter of how fast and how intense the rate of change is. If I were going to try to come up with a scale to graph TEOTWAWKI that is the tack that I would take to do so.

.....Alan.

lol @ directorio, touche

I'm always in the mood for a little taxonomy.

I suggest coopting Kardashev's scale for physical disasters above X. So, x-I is disaster that nulls the planet, x-II nulls Sol System (subtype "a" for just the star, subtype "b" for the entire system), x-III the whole Milky (intermediate scale for stellar clusters might be useful). You'd also need supertypes which Kardashev never got to:
x-IV for galactic cluster,
x-V for supercluster,
x-VI for the whole shebang.

Enjoyed the read,

Robert Kennedy

I like the taxonomy a lot.

At the scale of things you are talking about though, I think that it might be more appropriate to use the word 'biosphere' in place of the word 'ecosystem'. Ecosystem implies a more localized entity.

Mitch -- *excellent* suggestion. Thank you.

Under "Human Extinction", where does a "non-engineered" but none-the-less human-triggered event fit in on this scale? Along the lines of all those b-movies where nuclear experiments mixing in with something in the food chain inadvertantly create a race of monster insects and the like.

Isn't it amazing that no matter what tragedy we can think up, someone else comes along and thinks of something even worse?

So, I'd like to suggest a couple of other x-VI-type events, depending on the flatness of the universe:

x-VIa: the Big Crunch. If the expansion of the universe eventually slows and reverses due to gravity, then at some point in the future the universe will collapse into a singularity.

x-VIb: heat death. Entropy will increase to 1, and after 10^1000000000000 years or so the protons will have all decayed into diffuse energy. I guess one could call this the Big Whimper.

Hmm, nice. Your scheme needs work to qualify as 'existential' though. Glad to see some useful inclusions above.

Here are mine (two well-known finales)

Ea:"Begone!" roared God.

Eb: "What strange dream" murmured Xon, wearily rubbing his light-sensor.

Glad to help - thanks for taking it!

read Stephen Baxter's Destiny's Children. You'd might be surprised what possibilities there are to destroy humanity

E42: "There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened."

-- Douglas Adams

how about this one

'Game Over'?

You should include an exponential "time scale for recovery" column.

People Get What They Deserve: Climate Change and the End of Humankind
PIGS WANTED (PGWTD), or, "People Get What They Deserve":

Climate Change and the End of Humankind
on Planet Earth

by Charles C. Commons (c) 2006-3006

The end of humankind's time on Earth is coming to an end, and I welcome it. I can't believe I wrote that, but I did. Let me explain.

God knows, we've messed things up real bad, here on Planet Earth, and now it's time to pay the piper. Oh, it's not going to end in a nuclear armageddon, no. And it's not going to end because of the so-called "Clash of Civilizations" going on now with our friends the terrorists. No, the end is coming because of climate change, and it's too late to do anything about it now. Way too late.

Our fate has been sealed.

I should be in despair but I am not. I think we are getting what we deserve. We did our best, as a human species, but our best was not very good. We blew it. Climate change, according to the Stern Report, has already pretty much made it impossible -- read that word again: "impossible" -- to tackle global warming. We are done for.

We are about to be fried, frozen, fingered. Put that in your computer file.

As a species, we are done for. Period.

And while I don'tdespair over this, neither am I gloating, no. We are headed forextinction, and you know something, we deserve it. We sealed our own fate by our foolish, greedy, convenience-addicted actions.

Maybe it was in our genes from the very beginning, this coming demise. Maybe all this was meant to be, not some non-existant god or Creator Being, but by the fickle hands of fate itself. [If there really was a God, we wouldn't be in this predicament in the first place. Think about it. We did this all by ourselves. There's no use crying over spilled milk. We're done for.]

Oh, it won't happen soon, not in this lifetime, not in my lifetime or your lifetime. Give us 15 or 20 more human generations, 30 at most, and then it's curtains. The Earth will be fried. The die is already cast, it's in the cards. There's no going back. Sigh.

As human carbon emissions continue to grow and grow, the rate of climate change will accelerate and we will experience it sooner than you can imagine.

You think life is forever. It is not.

Human life is about to be deleted from the surface of Planet Earth. I give it about500 years. Stretch it to 1000 years if you wish, and that's okay with me. This is not an exact science. But it is science. We are done for.

The simple fact, the truth, is that we are headed for the exit ramp. Our rise as a species on Earth in a long, long history of cosmic time and Darwinian evolution has been capped. And we did it to ourselves. Us. You and me.

Cars. Airplanes. Factories. Coal plants. Massive industrialization. Oil. Technology. Convenience. Greed. We couldn't stop.

Our DNA, our intelligence, did us in. It's over. By the year 2500 -- okay, the year 3000 at the latest --we're history. And you know what? It doesn't matter. Not one bit. The cosmos does not care one iota. We came, we saw, we're leaving.

Because when you look at us, our history, our backstory, what did we achieve? Miracles, yes, and then some. But these miracles have done us in. Climate change cannot be unchanged. The course has been set.There's no turning back.

Let me put it this way: the Earth's experiment with the human species and most of the planet and animal species that evolved even before us is coming to an end. And we humans did it. We pulled the levers, we pushed the buttons, we pulled the triggers.

We burned too much coal, we guzzled too much gasoline, we used too much oil, we made too many factories to make our toys and vehicles, too many motorscooters, too many cars, too many smokestacks, too many people. We just didn't know how to rein things in. And now it's too late.

Well, 500 years is a long time to plan for the end. Start planning. I'm glad I lived in the last half of the 20th century and the first part of the 21st century. It's been a wonderful life, a wonderful ride, and I learned alot.

But even I, a common man with no PHD or expertise in anything, even I can tell you it's over. You don't have to read the fine print, either.The message is in plain English for anyone to read: increased concentrations of carbon dioxide in the atmosphere have sealed our fate. And I mean SEALED.

By 2500 -- okay, 3000, if you want to stretch it -- we will be goners. The Earth will remain, of course, good old Earth, our temporary home amidst the stars. But we, the human species, will soon be gone.

And there is not one single thing anyone can do about it. This is the sad,bare, bald, truth.

Greedy, hungry for entertainment and travel and technology, we did it ourselves, to ourselves. The rest, now, will be a long slow decline into annihilation of our species by unstoppable global warming and climate change. You might say this is depressing. I say it's reality, and we need to face reality. And start planning for the end. That is where our enterprise should go now: planning for the end of the human species.

I think that, when all is said and done, we deserved this. And people usually get what they deserve. Don't you agree?

So goodbye Human Civilization, Human Science, Human Evolution, Human Dreaming. No more Magna Carta, no more Beethoven or Mozart or Snoopy Dogg or J-Z, no more cellphones, no more PDAs, no more United Nations, no more blogging, no more cars, no more churches, synagogues, mosques, temples, shrines. Human life is soon to be a lost chapter in the Cosmos. Because of global warming and climate change.

Goodbye Humankind, it all its storied and multicolored and multisplendored variety! Ten billion people will soon be zero people. There will be no one left alive. There will not be one man standing. The Earth will be devoid of all human life, and most animal life and plant life as well. But some bacteria and slime will remain and continue...

You don't have to be a weatherman to know which way climate change is taking us. It is taking us to our end as a species. E-N-D. Period. Full stop.

Of course, I won't be here to witness those last pathetic years, weeks, days. Neither will you.

I had a good life at this time in cosmic time, and it was a very interesting exercise in conciousness, and I loved every minute of my existence. I am grateful for the very miracle of being here at all. Thank you Universe, thank you Evolution, thank you DNA, thank you Genepool!

But I've seen the future: come the year 2,500 (okay, year 3000 if you want to stretch it a bit) it's bleak. Bleaker than bleak. It's become dark at that point. The point of no return is that there is no return. READ THAT SENTENCE AGAIN SLOWLY!

We never adequately learned that lesson. Too late now. Sigh.

How much longer?

15 generations of family life, 30 at the most. And then it's over. Humankind is on its way out.

In a way, it makes sense. We did it to ourselves. We did it ourselves. We dug our own hole, while trying to build a towering temple to the sky.

It's okay. We had our chance. But we couldn't curb our appetites. Born from the swamps, we shall return to the swamps. Evolved from the void, we will return to the void. One might call it poetic justice. Celestial justice. Everlasting justice. Star life.

We came out of nothing, and we will return to nothing. Blame it on our genes, our sharp minds, our penetrating intelligence and human brains.

We are done for.

NOTA BENE: Even as you read these words, the planet's millions of engines, small and large, household and industrial, are purring, revving, singing their song -- and spewing CO2 emissions into the very atmosphere that sustains us, the very atmosphere that is now hastening our demise. At this very moment -- NOW! -- highways around the world are clogged, smokestacks are belching, gasoline is being guzzled, oil is being burned. Even as you read these words, it is too late. Too late. Too late.

Of course, you think 500 years is so far away, who cares? You should care. And you do. But it's too late........

--------------------------------------

LINKS:
INSIGHTFUL ARTICLE:
http://bostonreview.net/BR32.1/emanuel.html

NEWS

World at sharp end of climate change and humankind will end in 3000, warns 'blogger provacateur'

by LMN News Agency, New York

The world is at the sharp end of the devastating impact of climate change and there is nothing that can be done about it, according to an American writer who calls himself a "blogger provocateur", and says humankind will cease to exist by the year 2,500 or the year 3,000 at the latest.

Where on this table would you put 'Entire planet demolished to make way for a bypass'?

I urge everybody to read my article about one lost existential risk - i.e. risk of downloading and executing hostile AI during SETI search.

Is SETI dangerous?
http://www.proza.ru/texts/2008/04/12/55.html

Hmm - end of the world one-up-manship...

Z0 - Time travel allows someone to go back in time and prevent humanity from ever evolving.

Z1 - Time travelling super-tech posthumans go back in time and prevent the Earth from forming.

Z2 - Time travelling tech-diety-equivalent goes back in time and makes the Big Bang yield different laws of physics.