Global Population Forecast to Decline in Second Half of Century

[Jacob]

Findings

The global TFR in the reference scenario was forecasted to be 1·66 (95% UI 1·33–2·08) in 2100. In the reference scenario, the global population was projected to peak in 2064 at 9·73 billion (8·84–10·9) people and decline to 8·79 billion (6·83–11·8) in 2100.

The reference projections for the five largest countries in 2100 were India (1·09 billion [0·72–1·71], Nigeria (791 million [594–1056]), China (732 million [456–1499]), the USA (336 million [248–456]), and Pakistan (248 million [151–427]). Findings also suggest a shifting age structure in many parts of the world, with 2·37 billion (1·91–2·87) individuals older than 65 years and 1·70 billion (1·11–2·81) individuals younger than 20 years, forecasted globally in 2100.

By 2050, 151 countries were forecasted to have a TFR lower than the replacement level (TFR <2·1), and 183 were forecasted to have a TFR lower than replacement by 2100. 23 countries in the reference scenario, including Japan, Thailand, and Spain, were forecasted to have population declines greater than 50% from 2017 to 2100; China's population was forecasted to decline by 48·0% (−6·1 to 68·4). China was forecasted to become the largest economy by 2035 but in the reference scenario, the USA was forecasted to once again become the largest economy in 2098.

Our alternative scenarios suggest that meeting the Sustainable Development Goals targets for education and contraceptive met need would result in a global population of 6·29 billion (4·82–8·73) in 2100 and a population of 6·88 billion (5·27–9·51) when assuming 99th percentile rates of change in these drivers.

Interpretation

Our findings suggest that continued trends in female educational attainment and access to contraception will hasten declines in fertility and slow population growth. A sustained TFR lower than the replacement level in many countries, including China and India, would have economic, social, environmental, and geopolitical consequences. Policy options to adapt to continued low fertility, while sustaining and enhancing female reproductive health, will be crucial in the years to come.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7561721/

If this is true, there are a whole host of interesting implications for this across topics such as economics, immigration, geopolitics, resource needs, and who knows what else.

According to the above model, China's population won't quite be halved but shrinking by 48% is non-trivial. India would also lose significant population numbers. 23 countries would see their populations shrink by 50% or more.

The two things that spring to mind for me are:

- How will our economies adjust? What are the risks for economic collapse, if a population decline leads to a decline in demand?

- To what degree will this turn being attractive to immigrants into a positive? Will it change underlying anti-foreigner sentiment in EU countries (there's already significant tension between "we need more foreign workers in Denmark" and "but we'll kick them out the moment they lose their jobs" in Denmark)? Will there be opportunities for less developed countries with higher populations to turn that into a strength?

... but there are lots of potentially interesting (and troublesome) implications if these predictions are true.

And then there's the bit about the shifting age structure, with the global age shifting much older by 2100 as well, which has its own set of consequences, I think.

[Jacob]

According to the modelling, the West will reach its population peak in 2040, while the global population peak will come around 2064.

[HVC]

Post peak 2100 is still a billion more then we have now. That's just a lot of people. Increased automation will probably ease a lot of the economic fallout in the west.

[Jacob]

Post peak 2100 is still a billion more then we have now. That's just a lot of people. Increased automation will probably ease a lot of the economic fallout in the west.

I wonder what it'll do to the housing market. I guess in places with inbound immigration the housing markets may still grow... but on the other hand, if real estate continues to grow in price it may lower the appeal of those areas.

[Tamas]

2100 is past the timeframe I am concerned with.

[Jacob]

2100 is past the timeframe I am concerned with.

... even as an intellectual exercise?

[Sheilbh]

It's huge - half the world's population growth is going to be in Africa this century. Nigeria alone is projected to go from 200 to 800 million. It's going to have huge impacts even if numbers turn out to be lower than that and a huge shift in the world's economy and cultural centres of gravity.

There's also the politics of ageing populations - I think Japan and Italy have become the first countries already where more voters are retired than in work. That will have huge implications - I'd think about maybe young people getting two votes to counter it, or give everyone the vote.

The effect on housing, resources, immigration, growth, the environement - it's going to be huge. The ageing of China alone is going to be a huge story this century (and is a big point for the more Sinosceptic people - has China's moment already passed?).

[Tamas]

2100 is past the timeframe I am concerned with.

... even as an intellectual exercise?

The topic is interesting, don't get me wrong, but we spent decades worrying about overpopulation. If that's being proved grossly incorrect, than maybe this prediction is also grossly incorrect.

[Richard Hakluyt]

I think we need to protect the working part of the population and give the young a decent deal. So far it appears that ageing and declining populations treat the younger cohorts quite badly....this will only get worse unless we take measures to assist the younger generations.

[crazy canuck]

Post peak 2100 is still a billion more then we have now. That's just a lot of people. Increased automation will probably ease a lot of the economic fallout in the west.

I wonder what it'll do to the housing market. I guess in places with inbound immigration the housing markets may still grow... but on the other hand, if real estate continues to grow in price it may lower the appeal of those areas.

It will probably depend a lot on immigration policies.  Well that and general economic well being of a nation.  I like Canada's prospects on that score - assuming we keep the rabid right out of power.

[mongers]

I think we need to protect the working part of the population and give the young a decent deal. So far it appears that ageing and declining populations treat the younger cohorts quite badly....this will only get worse unless we take measures to assist the younger generations.

[Josquius]

[mono]
Terrible and worrying.
[/mono]

There's so many factors to consider around an issue as big as this.

*On the surface, excellent news. Its simply insane how much population has grown in the past century or two and getting vaguely back towards early 20th century levels would be a lovely thing...
*but its a massively unequal spread. Internationally massive growth is still expected in places where the world can least support it. Nigerias growth in recent decades and projected continuation is particularly worrying. We can ill afford the loss of more rain forest. And that's before considering global warming likely hitting such places worst of all.
*nationally the decline is unequal too. Towns aren't just across the land shrinking back to 1920s sizes. Rather some places are greying and rotting whilst others maintain their population.
*this greying of towns is already having huge political effects in the UK. Look at the data and you see this is one of the key factors behind the 2019 general election results.
*the mentioned issue of taxing the young to hell to look after the old is a big problem. And it will only lead to further declines in birth rate amongst other negatives.
*there's the question of whether this actually will happen. Birth rates tend to decline as qualify of life increases.... If we continue on our current path with adjusting to this however then established models have quality of life decreasing. But then you've the Eastern European example which seems to show this is a path of no return once you reach a certain level even if wealth then back steps.
*the current economic model is already a bit of a joke. By 2100 we have no choice but to have asteroid mining up and running even more firmly disrupting it. How will the transition to post scarcity socialism (or whatever dire save our skin alternative we get segued onto) alter things... Especially considering the likely environmental catastrophe unfolding alongside.