How big a loss of life could civilisation survive?

[MLS]

A fantastic book – one of my very favorites – that deals with this exact subject is Earth Abides by George Stewart. An airborne, highly contagious and highly lethal flu-like disease sweeps the earth and eliminates most of the human beings and certain other higher primates. The rest of the protagonist’s life as society regroups is described. It’s a bit technically dated now, having been written in the late 1940s, but the basic outline and social interaction is still valid.

Funny that the 1918 flu comes up for discussion. I just finished reading The Great Influenza: The Epic Story of the Deadliest Plague In History by John M. Barry. According to this, while that flu killed more people than the medieval bubonic plague, it was a smaller percentage. I think the 5 - 10% range is about right, allowing for the fact that in some places at some times, they stopped keeping accurate records; people were dying faster than they could be counted. Also according to Barry, this virus very likely originated in the central U.S., in swine. It was exacerbated by poor public health policy, plus the outright lying of virtually every government in the world; all kept insisting that everything was just fine, after all, “it’s only influenza.” People knew better and panicked. The governments, especially the U.S., kept sending train- and ship-loads of military personnel all over, despite the fact that virtually all had recently been exposed to this known killer illness.

In any case, he is of the opinion that it would be possible to deal with such an outbreak much more responsibly today. The main cause of death was actually secondary pneumonia. He also says that in some places society came really, really close to breaking apart entirely. Basic commerce of all kinds virtually ceased in many cities. Had it not been self-limiting, tending to burn itself out within a particular area within a month or two, things would have been much worse.

Finally, for a nice non-fiction portrayal of life in and after the time of the Black Death, try Barbara Tuchman’s Distant Mirror: The Calamitous Fourteenth Century. Again, something like 30% of Europe died, more in some places. Society changed drastically but survived. Of course, this was not a truly world-wide event. Had 100% of Europe died, the civilizations of the far east could have simply taken over. (Hmm. Interesting alternative fiction idea…)

In any case, IMHO society could survive a 30% loss and recover, but would take a serious hit. I think much over 50% and the resulting disruption, if it were truly world-wide, would take several generations to recover. If anything approaching 90% of all humanity ceased to exist, so would society as we know it. (I like *Earth Abides *for its portrayal of the complete loss of modern technology and starting over.) Homo Sapiens would continue to exist as a species, and isolated individuals would eventually re-form into clans or tribes, but it would take several centuries to start to redevelop anything remotely resembling modern life.

[tygerbryght]

@edwino

I am a MD/PhD student in molecular genetics planning to do ID (eventually). I get the flu vaccine every year but I can’t bring myself to become a hand-washing fetishist…

<shrug> I’m certainly not going to try to tell you how to protect your health.

Perhaps you can enlighten me, but I seriously doubt that your levels of handwashing are really going to do much more than scare people. IIRC from ID classes, most viruses don’t live very long outside of the body. Flu depends on aerosol inhalation for most infections. I found one cite from 1982 that influenza may live on surfaces for as long as 8 hours (rarely) and 2 hours (commonly), but most studies ignore this route of infection.

As you may have noticed, my posts are often very long. Believe it or not, I do try to keep them from turning into essays. And I’m certainly not interested in writing dissertations here. I’m not the person whose writing attracts people to this board … just another of the Teeming Millions.

Those levels of handwashing should be entirely sufficient to eliminate any viruses, as well as the vast majority of bacterial pathogens and normal flora, which is what I had in mind. Short of wearing sterile masks, none of us can do anything about aerosols produced by passing strangers (or coworkers, or family). But if people will try hard to keep their hands away from their eyes and mouth while away from home, and will wash as carefully as I described above, they have a high probability of avoiding infection via contact. I say “high probability” because the most carefully trained lab worker can sometimes goof, much less non-scientists going about their daily lives.

… For flu, the big risk seems still to be aerosols. Going out in public, you are always walking through a cloud of previous sneezes, coughs, and exhalations. It is unavoidable unless you are thinking about wearing a HEPA mask everywhere. With airborne transmitted viruses like influenza, I think you are just SOL no matter how little you touch your face or scrub when you get home.

The nose is the visible “front door” to a very specialized organ system. It adds sterile saline (“surplus” production from the eyes) to a variety of immune cells (and detritus). And of course, the surface presented to inhalations is mucous membrane, which has zillions more macrophages, etc., lurking at the surface, ready to attack invaders. It is so efficient that it cuts down some incredible-sounding percentage of the invaders. My mentor, Dr. Lida Holmes Mattman (immunologist and cell wall-deficient authority), loved to tell about a former student from her Immuno class one year (she always asked people in that class to do a nasal swab, which she then cultured). One student had C. tetani spores, yet he was - and remained - perfectly healthy. His immune system was doing its job.

Back to the OP,

The word “civilization” is quite nebulous. Ignoring the human nature arguments I made in my last post, there are a lot of pieces to our civilization that would not survive a 10% reduction in population, let alone a 50% or a 75%, as Chronos points out.

… There would be inevitable loss of knowledge as the survivors age and die before the at generations necessary to replace a 50% loss of population. I think we would have noticeable technologic backsliding with even modest losses (less than 25%) in industrialized countries.

I’m glad to see that you and others have pointed out some of the important losses that would result from even a relatively, mmm, “trivial” percentage population loss.

@Chronos

…

Also, “as bad as SARS” somehow fails to inspire any terror in me at all. I’m pretty sure that civilization can survive a loss of 0.00002% of the population.

You are referring to the losses as contained by quarantines of a strictness which had not been seen in something close to a century. The important piece of information was not the actual deaths per total world population, but deaths per infected class. Or even, if it makes you happy, deaths per known exposed class.

@MLS

A fantastic book – one of my very favorites – that deals with this exact subject is Earth Abides by George Stewart. An airborne, highly contagious and highly lethal flu-like disease sweeps the earth and eliminates most of the human beings and certain other higher primates. The rest of the protagonist’s life as society regroups is described. It’s a bit technically dated now, having been written in the late 1940s, but the basic outline and social interaction is still valid.

Funny that the 1918 flu comes up for discussion. I just finished reading The Great Influenza: The Epic Story of the Deadliest Plague In History by John M. Barry. … Also according to Barry, this virus very likely originated in the central U.S., in swine.

I, too, am very fond of Stewart’s book. However I have a problem with your cite of Barry. I don’t doubt he said it “very likely originated in the central U.S., in swine.” However, that’s now demonstrated to be not the case. The virus was recovered from one of the 1918 victims, and analyzed. I’ve cited the news article from National Geographic twice in this thread; that’s enough. However, you can find that link, as well as one to an online epidemiology literature review in my first post in this thread, #20. If you were sufficiently interested to read Barry’s book, I’m sure you’d find those two links worth pursuing.

[Lumpy]

@MLS

Had 100% of Europe died, the civilizations of the far east could have simply taken over. (Hmm. Interesting alternative fiction idea…)

Been done!
http://www.powells.com/cgi-bin/biblio?inkey=8-0553580078-0;partner_id=28585;;slnc=1

[MLS]

Lumpy, thanks! Cool!

tygerbryght, I just now re-checked your Nat Geo link and see your point. Verrry interesting. If I’m reading the URL correctly, this article is from February 2004, which would indeed be more recent than Barry’s book. However, that article also says,

Some scientists believe wild waterfowl are the natural reservoir for the influenza virus. Since pigs can be infected with both avian and human strains, they are also thought to be an intermediary in the transmission process.

I do recall that Barry was careful to say that the swine strain theory was not definitive, just the most likely of a couple of alternatives. Looks like NG agrees on the USA origin, though.

[EvilGhandi]

Bryan Ekers,

Excelent insight. IIRC, during WWII, US Naval vessels were redundantly manned enough to continue full strength combat operations with a 75% casualty rate. (providing the ship remained operational)

Given the size or the US nuclear fleet It could feasibly extort oil and supplies for its members and secure a fixed port for repairs.

This is a sci fi plot in the making if I ever read one.

[Cforn]

The Book of the Subgenius leaves no room for abiguity in situations like these:
“Waste no time in turning rogue.”

Ninja - There is no question. I am fully prepared to offer an exclusive “Long Haired Woman - Special Skills: Draping and Wit” position to you.

I’ll be the one with the booze and good eats - and the means to hang on to them.

See you at the Apocolypse!

[FX45_4Ever]

Hmmm…

What about if all Christian’s dissapear?

Now what if only a specific sect remained?

Like only the Amish, or only Athiest, or only Jewish, or only blacks, or only Canadians? :eek:

THEN would the human species survive?

[MaryEFoo]

It’s OK, they’d do what humans always do, they’d schism and start contending.