There's a deceptively simple question that's been bugging me this week, and it is this:
What is the minimum number of people you need in order to maintain (not necessarily to extend) our current level of technological civilization?
There are huge political ramifications hiding behind this question. Let me unpack them for you.
Conservative politicians in the US — and elsewhere — get a lot of mileage from appeals to false nostalgia, to a yearning for a time when things were simpler, everyone was sturdily self-sufficient or knew their place (or both), and government was small (sometimes small enough to drown in a bathtub). Nostalgia trips manifest themselves in all sorts of curious places. In SF (the literary field I know most about) we have the perennial libertarian/space colonization nexus.We have Ayn Rand, and her wish-fulfilment nerd fantasy of a world sustained by a tiny, overworked minority of geniuses who, if only they could demand a level of rewards corresponding to their work, would be rich beyond dreams of avarice (and able to make the trains run on time). Outside it, we have the peculiarly rustic aspirations of the green fringe, who'd like to see a world of five million or so pre-industrial humans living in harmony with nature. In the Republican party of the United States we see rhetoric couched in hatred for "big government", and among the UK's conservatives we see an almost masochistic addiction to cuts in public spending framed with calls for a big society in which many current government services will be delivered by voluntary citizens groups instead.
I think these ideas are mostly delusional because they rely on a fundamental misapprehension about the world around us — namely that we live in a society that can be made simple enough to comprehend.
Let's take a look at the superficial structures around us. How many people does it take to design a new automobile? Back in Henry Ford's day, it needed an office full of draughtsmen, a handle of senior engineers to sort out each major mechanical subsystem (gear train, engine, electrics, brakes, suspension, bodywork), and experts on coachbuilding to dictate the shape of the bodywork. There would be time and motion men to dictate the speed and sequence of assembly line activities, and more drafting work to design the tools the production line workers would use ... it took the effort of a few hundred men.
But modern cars are different. A typical 2010 automobile may contain roughly 20-30 electric motors and actuators (for everything from the central locking system to the air conditioning and the motorized seats and windows). There's a similar number of microprocessors involved in everything from the engine and gearbox management systems to the entertainment, navigation, communication, and accident mitigation systems (for example, the sensors and microprocessors that control the sequence of pyrotechnic detonators that inflate air bags, tension seat belts, and collapse the steering column in event of a collision). The in-car electronics alone require on the order of 10-20 million lines of code to run all these services — which implies the combined efforts of thousands of software developers, never mind the small army who design not only the body panels but the handling tools the production line robots use to install them. Cars are no longer user-serviceable because they're nearly as complex as 1960s airliners.
And as for your smartphone? The damned thing has a component count somewhere between ten major subsystems and frame components and a hundred billion (if you go down to the smallest scale and count the capacitors in its FLASH memory). The number of fab lines on the planet that can make memory chips of that density is limited, and they rely on rare elements mined only in exotic locations and in tiny abundance.
Medicine: let's not go there. Back in the late 19th century, we had doctors, nurses, surgeons, pharmacists, and dentists. Today, each of those professions has exploded into platoons and battalions of sub-specialities, and their roles are supported in turn by complex industries full of strange niches.
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).
As to those political implications ...
Firstly: no, you can't simplify a complex society that runs on just-in-time delivery and a host of specialities. You need a huge training back-end to provide for the thousands of skilled graduate-entry niche occupations. You need an efficient just-in-time delivery system to keep everyone supplied with food, water, power, shelter and whatever else they need — it's that, or accept huge inefficiencies in your supply chain that wipe out the gains produced elsewhere.
Secondly, seemingly similar artefacts (cars, phones, airliners) have invisibly accreted complexity. The complexity makes them better (safer, more economical, more luxurious) than their predecessors, but vastly more difficult to engineer; stuff that used to be fixable by shade-tree mechanics and jobbing electricians has receded over the horizon. Back in the early 19th century, the complement of a sailing ship could expect to maintain the ship in every significant way using tools and expertise that they could carry aboard the ship. Today in the early 21st century, that's not an option with airliners or probably even automobiles.
Thirdly, the complexity embodies in these new products means that their production is dependent on a complex web of lower-level specialities.
Fourthly, there are more side-effects to keep track of. Exotic materials mean exotic contamination events from waste dumping, for example.
Fifthly: space colonization? Get back to me when you've tracked down how many people it takes to design and build a space suit. (The number is in the hundreds, if not the thousands.) More realistically, we won't have autonomous off-world colonies unless and until they can cover all the numerous specialities of the complex civilization that spawned the non-autonomous, dependent-on-resupply space program. Or, to put it another way: colonizing Mars might well be practical, but only if we can start out by plonking a hundred million people down there.