… as long as they are healthy, well fed and well educated
Much of the panic about falling birth rates can be dispelled once we realise that (barring catastrophe) there will almost certainly be more people alive in 2100 than there were in 2000. But what about the distant future? Dean Spears, co-author of After the Spike has kindly provided me with projections showing that with likely declines in fertility the world population will decline by half each century after 2100, reaching one billion around 2400. Would that be too few to sustain a modern civilisation ?
We can answer this pretty easily from past experience. In the second half of 20th century, the modern economy consisted of the member countries of the Organization For Economic Co-Operation and Development (OECD). Originally including the countries of Western Europe and North America, and soon extended to include Australia and Japan, the OECD countries were responsible for the great majority of the global industrial economy, including manufacturing, modern services, and technological innovation.
Except for some purchases of raw materials from the “Global South”, produced by a relatively small part of the labour force, the OECD, taken as a whole, was self-sufficient in nearly everything required for a modern economy. So, the population of the OECD in the second half of last century provides an upper bound to the number of humans needed to sustain such an economy. That number did not reach one billion until 1980.
Things have changed since then with the modernization of much of Asia and the rise of China as the new “workshop of the world” in manufacturing. But the history is still relevant.
We can also look at the US> Even today, trade accounts for only around 20 per cent of US economic output. Given a US population of 400 million, it is reasonable to suppose that the production of goods and services elsewhere for export to the US might account for another 100 million people. Most of the needs of these people could be met from within the US economy, but let’s suppose that they employ another 100 million in their own countries. That’s still only about 600 million people who, between them, produce all the food they need, the manufactures that characterised the indsustrial economy of the 19th and 20th century, most of the information technology the world relies on, and a steady flow of technological and scientific innovation.
At the lower end of the scale, Charlis Stross has estimated a minimum requirement of 100 million people, a number that might increase in a society even more technologically complex than our own. But since current demographic trends won’t produce that number for nearly a millennium, we probably don’t need to worry (unless we want to colonise space, the context of Stross’ estimate)
In summary is no reason to think a billion people would be too few to sustain a technological economy. But would a world of a billion people look like?
It’s foolish to try to say much in detail about life hundreds of years from now. What could a contemporary of Shakespeare have to say about the London of today? But London and other cities existed long before Shakespeare and seem likely to continue far into the future (if we can get there). And many of the services cities have always provided will be needed as long as people are people. So, it might be worth imagining how a world population of one billion might be distributed across cities, towns and rural areas.
Australia, with 5 per cent of the world’s land mass and a current population of 25 million, provides a convenient illustration. A billion people would populate 40 Australias, with twice Australia’s current population density. However, around half of Australia is desert or semi-arid (estimates range from 18 to 70 per cent, depending on the classification, and not many people live there. So, the population density of a billion-person world would look pretty much like that of urban and regional Australia today.
Opinions in Australia (as elsewhere in the world) are pretty sharply divided as to whether a bigger population would be a good thing, but it’s unusual for anyone to suggest that we are spread too thinly. On the contrary, congestion, sprawl and the conflict between environmental preservation and housing are seen as the price to be paid for a larger population.
A billion person world could not support mega-cities with the current populations of Tokyo and Delhi. But it could easily include a city the size of London, New York, Rio, or Seoul (around 10 million each) on every continent, and dozens the size of Sydney, Barcelona, Montreal, Nairobi, Santiago or Singapore (around 5 million each). Such a collection of cities would meet the needs of even the most avid lovers of urban life in its various forms. Meanwhile, there would be plenty of space for those who prefer the county
With only a billion people we wouldn’t need all the space in the world. The project of rewilding half the world, now a utopian dream, could be fulfilled, while leaving more than enough room for farming and forestry, as well as whatever rural arcadias followers of the simple life could imagine and implement.