It is interesting, then, to look at Totality Fertility Rates. The TFR of a population is the average number of children that an average woman will have across her reproductive life. To maintain a constant population, the TFR needs to be about 2.1 in industrialized countries, and higher in developed countries.
The UN has compiled useful TFR research and projections .
In the left window select Total fertility. In the right select a region. Now hit Display.
Here are the TFRs for the world population across time.
Note that it steadily drops, from 4.92 in 1955, to 2.56 today. We should hit replacement fertilitity rates by 2040.
Yet the population will continue to grow after this. Why? It’s because the first generation of women with TFR less than 2.1 was borne by women with TFR greater than 2.1. There are still large numbers of women giving birth faster than the older generation dies. The important thing is the trend – the population will peak. Various estimates place the peak a little above 9 billion in 2050, give or take.
Regions with Currently Low TFRs
We know industrialized countries have very low TFRs.
Japan - 1.27 today, 1.60 2050.
Russia - 1.37 today, 1.83 2050
Western Europe – 1.59 today, 1.79 2050
And China
China – 1.77 today, 1.85 2050.
Note that all of these are projected increases, even though the historical data is consistently decreasing. It’s more logical for these trends to continue their momentum. In any case, these countries are losing population, sometimes quite rapidly.
Check out the US – 2.09 now, and falling to 1.85 very soon. It takes immigration to maintain a young workforce. And Mexico? 6.70 in 1950, only 2.21 today, and dropping soon to 1.85.
Regions with Currently High TFRs (Developing Countries)
"But", people are saying, "what about developing countries? They wont stop breeding." In fact, although developing countries still have very high TFRs, they've been dropping like a rock and show no sign of stopping.
India - 5.91 in 1950, 2.76 today, 1.85 2050
Sub-Saharan Africa - 6.57 1950, 5.08 today, 2.46 2050
And so on.
The Sweet Spot
To be productive, countries need more than a large population. The need a high ratio of labor force to dependents (elderly and children). Unfortunately countries with low TFRs are rapidly graying. They are not breeding enough workers to support their old age. Japan is concerned about this issue. The US worries about Social Security viability.
Immigration will be an increasingly important solution (current unemployment and immigration concerns don't factor here - I'm talking about future trends). Immigrants trend young, and they pay taxes and social security and medicare.
Some countries will hit the sweet spot. When a country has a high TFR, the workers must support many children. When a country has a low TFR, the workers must support many elderly. But when the TFR is dropping, there's a certain point where there's a big surge of working age people with fewer elderly and children to support, allowing great productivity. This happened previously in Europe and is going on in Asia and Latin America. When it happens in Africa, they should be ready to take advantage of it.
Conclusions
Increased standards of living decrease TFRs, and decreased TFRs increase standards of living. Female education and availability of family planning decrease TFRs. It appears that women, across regions and cultures, when given a choice, want fewer children.
The population will level off. Maybe it will be 9.3 billion as predicted. Maybe a bit more, let's say 11 for the sake of argument. But it won't follow old growth rates, so it won't jump to 30. Sure, 11 would be tough to manage. Living standards are increasing, so individuals demand more food, more meat, and more gas. Farmland will get stretched and global warming may decrease farmland availability. But it's a manageable issue. Education and birth control, good farming practices, and investment in technology will help. It's going to be alright.
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