global population

I’ve written a bunch about oil supply on this blog. That’s pretty unusual – most people today, if asked to identify the biggest crisis about to hit humanity, would identify climate change. A few would talk about water supplies, fewer still would talk about oil.

But there’s another problem, one which is spreading rapidly but hardly anybody talks about, perhaps because it’s so counter-intuitive. That problem is that our population is spiralling out of control – downwards.

sub-replacement fertility

The spread of sub-replacement fertility (ie, not having enough babies to replace the parents) is one of the great demographic surprises of recent years. Originally believed to be limited to just the wealthiest developed nations, now even “3rd world” countries have dropped below the replacement rate. Places where they are having lots of babies are now exceptional on the world stage.

This runs counter to our embedded notion that the worlds population is too high, and that like a yeast culture we’re poisoning our environment with our effluence. People worry about the Chinese, the Africans, all without realising that almost everywhere we’ll soon have too few people, not too many.

One interesting exception to this is America. With a replacement rate of 2.01 (see the CIA world factbook for the figures) they are not that far below the needed rate in industrial countries of 2.1 (2 children to replace the parents plus a fudge factor to make up for infant mortality). According to Wikipedia, if you break it down into states the picture becomes clearer – the coastal states have more European like birth rates reflecting similarities in culture, whereas the southern/border states have higher than replacement birth rates – probably due to different value systems.

the causes

Nobody really knows why birth rates are so low worldwide. My speculation about value systems above is just that, speculation. All kinds of explanations have been proffered – the desire of women to have a career and their reluctance to sacrifice to have children, the spread of birth control, the increasing social acceptability of being “child-free” and so on. Given the wide range of cultures the problem affects its tempting to suggest a biological cause, but the existence of exceptions like the American south, the Gaza strip and Saudi Arabia seem to disprove that.

But if birth rates are too low, how comes our population is still going up? The main reason is extra longevity. If people take longer to die, even if we are adding new people too slowly, there’s still going to be a period of time in which the old guard haven’t died off yet – so the population will rise, before crashing down as the older generations start to pass away.

Another reason is that China and Africa are not afflicted by this trend yet, and they are pretty huge places. Partly this is economic (death rates are very high in Africa so there is incentive to have more kids), and partly cultural – see the recent reports of civil unrest in China caused by the 1-child policy, spurred in part by an ingrained preference for boys.

While some nations like the UK are sustaining their populations by allowing immigration, the immigrants soon adopt the lifestyle of the host country and also stop breeding, so this can only be a temporary fix. Even if a massive wave of immigration were to be allowed from Africa and China, people aren’t simply assets that can be moved around the globe to make the numbers work … the social and racial tensions huge waves of immigration would cause in Western countries are considerable, especially in time of economic downturn.

In other words, it’s meaningless to talk about “world overpopulation” because it’s possible for some societies to be overpopulated and others to be underpopulated simultaneously.

the effects

Nobody is really sure what the effects of firstly an aging and then a rapidly shrinking population would be. The only parallels we know of are after huge, devastating epidemics like bubonic plague …. but these occurred when society was structurally much simpler, and the amount of critical infrastructure that needed to be maintained was lower.

We can see some of the micro-level effects right now with localised skills shortages in areas like engineering and infrastructure. These aren’t caused by population decline yet but are perhaps a preview of coming attractions, if nothing changes. Major projects, some of which are needed to keep things running, keep getting delayed due to lack of experienced workers. This problem is especially acute in the oil business but affects others too – for instance, there is apparently a lack of linesmen in the US electricity industry.

Market economics would suggest that as pay rises more people would enter the industry to meet demand, but that doesn’t actually seem to happen …. turns out salary is only one of many factors people weigh when choosing a career (assuming they choose at all, most don’t). A factor repeatedly identified is that a lot of the people who would have gone into industrial engineering or other “heavy skills jobs” in an earlier time are now choosing careers in IT, which provides both good pay and a respectable desk job where you run no risk of injury and don’t have to wear a hard hat. The IT industry appeared out of nowhere in the 70s and has grown at a ridiculous pace since then, it’s perhaps not surprising that it worked by siphoning off people that would have been doing other things.