Fifteen years ago, population growth was one of America’s core advantages because it had a high fertility rate close to the replacement rate of 2.1 children per woman.

Add copious immigration on top of that, and our demographic future seemed assured 
Projections had the U.S. increasing its size relative to its main potential rival, China, over the course of the century. The country’s youthfulness implied a bright future for its:

📊Asset markets
⚕️Solvency of its pension & health care systems 
This vision of demographic dominance has since gone up in smoke.

The 2020 Census indicates that the population is growing more slowly than at any time since WWII. It's not shrinking yet, but if we don’t correct course, we are certain to stagnate in size 
Why is this happening?

Ultimately there are two ways a nation’s population can grow: Having babies, or taking in immigrants. The U.S. used to be very good at both of these things, but no longer 
By 2018 the U.S. total fertility rate has fallen to around 1.73, in line with the likes of Denmark and the U.K.

And that was before Covid-19. Some estimate fertility is now down to 1.6, similar to Germany 
Some of this is happening for good reasons. For example, the teen birth rate has fallen enormously:

🗓️1990: 61.8 births per 1000 teenage girls
🗓️2018: 17.4 births per 1000 teenage girls

That’s a positive development; we don’t want kids having kids 
Another positive cause of fertility decline has been the assimilation of Hispanic Americans to U.S. fertility norms.

In 2007, Hispanic American women had about 67% more kids than their White counterparts; by 2018, the difference had shrunk to under 20% 
The fertility drop isn’t completely benign.

The average number of children women say they want has actually risen, to 2.6. That implies that American parents lack the financial resources to have as many kids as they would like 
On immigration, too, the once-mighty U.S. has faltered. Immigrants are still coming in, but at a much lower level relative to population.

With immigration and fertility both down, the U.S. is projected to age rapidly 
Here’s why that matters: Old people stop being able to work, which means they must be supported by the efforts of younger, working people.

As the population ages, an increasing financial and physical burden is put on the young 
In 2010, the number of working-age adults per older adult was 4.8; by 2060 it’s projected to be only half that — doubling the economic burden on the young.

This, and a reduction in productivity growth, will hold down living standards 
Opponents of population growth argue that it’s bad for the planet. But this isn’t necessarily true; over the past few decades, even as the U.S. population has continued to grow:

🌊Fresh water use has fallen
☁️CO2 emissions dropped
💡Energy use stayed flat 
A national population policy would be wise:

➡️Allow in more immigrants
➡️Lower the cost of having children

Happily, Biden is making steps towards doing this 
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