The Quiet Earth.

It's become a sort of standard assumption in science fiction that an apocalyptic event would mean the end of civilization.  Depending on the event, that would certainly be the case - obviously the sort of destruction caused by an extinction level asteroid strike or a nuclear war would push things below the level at which our current society functions on a planetary basis.

But not all end-of-the-world scenarios involve extreme property damage. Is the threshold for civilization based in any way on the size of the population?

Let's posit a pandemic scenario which wipes out 95% of the world's population, but without the sort of theatrics which normally accompany this sort of disaster in fictional descriptions.  In other words, maybe we don't panic. Yes, we swamp the hospitals, and yes, an awful lot of people die, but why would that make the government collapse?

We'll set some ground rules. Our nemesis is an untreatable contagious disease that kills its victims in less than a week, and it's spread by airborne transmission.  As with Captain Trips in Stephen King's The Stand, if you catch it, you pretty much die.

The current population is 7.5 billion people, so we're left with about 375 million after the infection burns out, which is more or less the population of the world in 1000 AD.  (In reality, the less organized and compliant a country's response to an emergency, the greater the loss of people, but let's keep the math simple and just say that 1 in 20 people are left alive right across the board, without any bias toward either democratic societies or brutal dictatorships.)

So we assume that the response to the catastrophe is controlled and organized.  Inevitably, there would be a certain percentage of unrecorded deaths, but for the most part, the victims come to their end in hospitals or under some other form of final care.  A brutal simplicity is enforced: there's no time for individual burials, just daily truck convoys to the mass burial sites. Over time, there are fewer trips - and fewer truck drivers - until eventually the virus burns itself out.

What does the world look like afterwards?  How many links can break before the machinery of our society ceases to function?

Logic says that we condense, that everything pulls in toward the center - whatever the center happens to be.  We're left with massive amounts of unnecessary infrastructure, but the framework of everyday life is still there, and I would think that in some odd way, it would all balance out.  If you were a bus driver before the epidemic, you're still a bus driver, and you have about as many passengers on a daily basis, but 19 empty buses are left to rust at the depot.  Karli and I live in a small apartment building that holds about 20 people - now there's just one of us, no more lineups for the washing machines.*

But what if our landlord is dead?  Is there anyone left to collect the rent? For that matter, why would anyone stay there - 19 out of every 20 homes are now empty, why stay in an apartment? How would the government control squatting?  Or would they even attempt to?
  
Perhaps looting and squatting would become acceptable activities as the government urged people to clearly indicate what homes are inhabited, and created a system by which you apply to take over the empty home of your choice. The remaining locksmiths would become very busy, especially people who can re-key vehicle ignitions.  As with houses, there are a lot of cars left, and no reason not to trade up.

A certain percentage of empty buildings might simply be demolished.  After all, if everyone living in three story walkups like ours has moved into an empty house, it seems wiser to simply eliminate those buildings rather than abandoning them to decay and eventually collapse.

Businesses combine and vanish, as employers without staff seek out workers without bosses.  As with residential property, there's a process in place to take charge of rare materials, inventory and factory space. 

When it's all over, it's a quiet world.  There are no traffic jams.  There are no lineups.  And hopefully it's a kinder, gentler world than the old one, a world where people are more tolerant, friendly and affectionate.  If 95% of the people you loved were gone, how could you not treasure the ones who were left?

- Sid

* In my heart, I would hope that there would actually still be two of us.  And the cat, of course.