[BRIEF NOTE] On some irreducible minima

[rfmcdonald]

Another Charlie Stross blog post, "Insuffucient data", picked up by Marginal Revolution and over at james_nicoll's blog (among other places), started up a very interesting thread. How many people would be necessary to keep our high-tech civilization running?

Around 1900, it took the effort of about 20-30% of a nation's work-force to provide food for everybody; and another 30-50% working in factories to produce clothing, machinery, and processed materials like bricks and billets of pig iron. Today, we only need 0.5-1% of the work force to feed everyone, and another 1-4% working in industry to produce the basics — but the microspecialities have exploded, to the extent that a lot of our needs seem to require a trans-national economy to provide. There are only two vendors of wide-body airliners on any scale today, Boeing and Airbus, and both of them are effectively multinational consortia (more than half the components of the Boeing 787 Dreamliner are produced overseas, and shipped to Seattle for final assembly). There seems to only be room for one vendor of super-Jumbo airliners — if Boeing and Airbus tried to exploit that niche simultaneously, they'd both starve — so they appear to be avoiding conflict in that (and some other) area(s). And so on.

So. I ask: how many people does it take, as a minimum, to maintain our current level of technological civilization?

I'd put an upper bound of about one billion on the range, because that encompasses basically the entire population of NAFTA and the EU, with Japan, Taiwan, and the industrial enterprise zones of China thrown in for good measure. (While China is significant, more than half of its population is still agrarian, hence not providing inputs to this system).

I'd put a lower bound of 100 million on the range, too. The specialities required for a civil aviation sector alone may well run to half a million people; let's not underestimate the needs of raw material extraction and processing (from crude oil to yttrium and lanthanum), of a higher education/research sector to keep training the people we need in order to replenish small pools of working expertise, and so on. Hypothetically, we may only need 500 people in one particular niche, but that means training 20 of them a year to keep the pool going, plus future trainers, and an allowance for wastage and drop-outs by people who made a bad career choice. Higher education accounts for 1.8-3% of gross spending in the developed world, with primary and secondary education taking a whopping chunk on top of that (if you spent 10 years in a school with a staff:pupil ratio of 1:10, then you soaked up a person-year of time; there may be more labour going into pre-university education than goes into agriculture and industry combined).

This has obvious implications since, as Charlie and the commenters note, our civilization has any number of irreducible complexities, and necessary redundancies to compensate for all manner of losses (people deciding they don't want to follow particular careers after all, say). A hundred million people might--if everything's well planned--be able to sustain a technologically advanced civilization, a world that's overall much more modern than ours might be able to do what we do with less, and a world that simply has a small population would likely do a better job than a world depopulated by catastrophe, but still. For progress, you need people, all kinds of people.