How many people are needed to maintain current living standards?

Andrew West, citing Charlie Stross, sends along a question:

What is the minimum number of people you need in order to maintain (not necessarily to extend) our current level of technological civilization?

I'll treat this as a steady-state question and not commit to any particular time frame.  Stross wrote:

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.

My casual, seat-of-the-pants estimate is that a world of one billion people — mostly from the wealthier countries — would be about fifteen percent poorer for those people than today's world.  Even very poor countries often supply valuable commodities or raw materials, in addition to buying some exports and expanding the scope of both comparataive advantage and increasing returns.  What's the implicit assumption about settling those countries and reaping those resources?  Are we dealing with a Nigerian government backed by five million very poor Nigerians?  Or is Nigeria an empty land, open to settlement as a southern colony of Switzerland?  I am assuming the former and that means those countries have much smaller economies, and higher fixed cost problems, than today.

Under this scenario the United States loses much of its Asian immigration and Arab immigration, two successes even if you disagree with me about the successes of Latino immigration.

Alternatively, the thought experiment could be shrinking the world's population but keeping the rich-poor proportion constant in the population.  In that case the number of people needed to maintain current standards of living, or even fifteen percent less, is much higher.


Since reading the original article I've been thinking about it the other way round - what's the maximum technological level you can reach with our current population? Does technological advancement slow down or stop with population growth?

Is this how many people should be on our planet right now?

But the fishing would be better?

A somewhat interesting question, but his assumptions are pretty flawed (see the comment about China).

Also, it was amusing seeing his framing of it in the political sense. If there is one thing that is bipartisan in politics, it is the belief in the inherent goodness of the simple life of the past.

Is any standard of living maintainable without growth? We can substitute technology for people, but the entire momentum that keeps the economy in motion is predicated on growth. Without it civilization winds down on its own becoming a zero sum struggle, profitless and pointless.

Lord: you can still have economic growth without population growth due to increasing efficiency. That's partly why I'm interested in the idea of how much growth in knowledge is related to growth in population.

is this a cornucopian question?

how long do the natural resources necessary for that civilization last?

I assume this abstracts from the problem of getting there. Shrinking populations place a huge burden on the young whether through the Social Security system or the old fashioned taking care of parents.

In the shiny happy future everyone will be a highly intelligent specialist? Even if you assume some high powered AI added into the system (but not assuming what could genuinely be described as artificial life or intelligent self-replicating machines), it's going to take everything society has just to keep the standard of living at a constant level with 100 million people. There would be very little margin for error and where's the spare capacity for disaster relief and freak events? If there's only 500 physicists, they could all meet for the global physics convention. What if half of them ate the salmon mousse?

Any type of sci-fi future in space will require billions more people, not due to the necessity of taxing Earth's resources, but for the massive amount of specialization required.

hmmm, I read the question as "how many people are required to maintain the 6 billion people in the current standard of living?", which is about 1 billion.

The more interesting question is "how many people are required to maintain all 6 billion people at the US standard of living?"

"Current" living standards is probably the trickiest part. Go back 70 years, and you could probably sustain an industrialized civilization of that era (such as the US) on a population of 50-100 million as long as they had access to plentiful natural resources. The collapse of the trading system left many of those economies near-autarkic anyways, including the US.

Beyond that, once you get into the area of economies of scale on things like electronics and modern machinery, become difficult to guess. The Soviet Union seemed to be able to support some degree of sophisticated technology beyond your standard '50s industrial stuff, and that was with a grotesquely inefficent state socialism economy.

Maybe I've drunk too much of the Julian Simon kool-aid, but I think this question is fundamentally evil, and I would refuse on principle to answer it.

It's because you're misreading the question. He's not advocating drastic cuts in population down to a certain point - he's simply asking how many people are necessary in order to keep modern civilization up and running.

It's more relevant than you might think. What if, for example, a disease were to sweep through humanity, killing 40% of the population in the process? Knowledge along the lines posed by the question would be very useful in developing post-plague plans for reconstruction.

"in 1970 the US population was 200 million. Now it's 310 million. Was that increase good for Americans who were around in 1970?"

I don't know. Was it?

When showing your evidence for your answer, please consider a concept called "opportunity cost." Economists seem to forget all about it when talking about immigration.

Would the world miss Charlie Stross?

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Steve Sailor - if you don't know if matters improved in the US between 1970 and 2010, or between 1790 and 1830, why did you bother asking your question about whether an increase between 2010 and 2050 would be an improvement? Apparently you think that becoming richer and having a higher life-expectancy doesn't count (this is what I mentioned in my comment), so what does count as better for you?

When showing your evidence for your answer, please consider a concept called "opportunity cost. Economists seem to forget all about it when talking about immigration.

What is the opportunity cost of asking questions like "Will that be good for current Americans?", when you don't have the foggiest idea of whether increases in American population in the past were a good idea or not? What gain do you expect from talking about immigration, when your starting point is so muddled? And, under these circumstances, why are you criticising economists for forgetting about opportunity costs?

I like the idea of Southern Switzerland. What the Swiss could do with Nigeria!

IVV - Ah, okay. I find your model implausible though. You appear to assume that there are no gains to scale, or returns to increased specialisation of labour, such as Stross mentioned, or I did when I mentioned the increased survival rates at bigger hospitals. Is there a reason that you think that there are no gains to scale from production?

You also mention the concept of "no longer needs the full resources of the planet." But the "full resources of the planet" are not fixed, for example oil used to be an annoying waste product, and the invention of the silicon chip massively increased the usefulness of sand. If we lose all those productive minds thinking up ways to use the resources of the planet, won't the available resources shrink?

Another optimist weighs in...

Sure, with a smaller population you get more resources per capita. But primary extraction is a shrinking portion of human wealth; most of our value added comes in secondary and tertiary and will continue to do so. Most gains in human productivity come from mechanisation and specialisation. As others have said, economies of scale are very important and dwarf resource effects. Obsessing about lower resource consumption or more resources per capita is to fail to understand the last 200 years of economic history.

And furthermore, as long as the marginal product less consumption of the nth human is greater than the mean (n-1) set human then adding people increases mean human welfare. So let's have none of this nonsense about optimum smaller-than-present populations.

And even high population densities have an upside; cities see mean costs of transport and interaction per capita fall dramatically. Imagine what your life would be like if you had to travel 2.5 times as far to everywhere for the same service . That's your even-spread 6/7th reduction for you.

For what its worth, the question is probably better rephrased in terms of how much a reduction would cost the survivors. Because it would cost them, not be cost neutral. So my answer is "no lower level supports current level*".

*Caveat: I suppose you could selectively cull the poor or unproductive or just plain foreign to raise your residual welfare but that doesn't seems to be the spirit of the question. I also charitably hope this isn't what the paleo-greens are suggesting? Sometimes I wonder....

Tracy W: Your healthcare example is a good counter-point.

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