UPenn economist @JesusFerna7026 just gave an important talk called The Demographic Future of Humanity.
Key points:
(1) Birth data is much worse than the UN reports,
(2) UN projections are absurdly rosy,
(3) Economic growth will be low, and
(4) Immigration cannot fix this.
🧵
First, Fernández-Villaverde notes that in country after country, the UN's birth figures are far higher than what those countries officially report.
For example, the Colombian government reports births 25% lower than what the UN claims. In Egypt and Türkiye, the gap is ~12%. 2/8
On top bad birth data, the UN's population projections are absurdly optimistic. In most countries birthrates have been dropping like a rock. Yet the UN projects birthrates will bounce right back up.
There is no evidence for this. The causes of low birthrates haven't reversed. 3/8
In fact, yesterday @BirthGauge (a must-follow account) released new fertility data, based on the latest 2025 reporting by national governments.
Contra UN projections, the birth decline is accelerating around the world, with many countries seeing double digit drops in 2025. 4/8
Economic growth will be low, Fernández-Villaverde explains, and the math is simple.
Output growth is just productivity growth times workforce growth. Even if productivity keeps growing at 2%, a shrinking workforce means that GDP growth would average just 1% instead of 3%. 5/8
That 1% baseline growth is a huge problem for governments.
US debt is soaring, and the stated plan is for GDP growth to outrun the debt, as it has in the past.
But low birthrates mean that even if productivity keeps improving, GDP growth will be much too low for this to work. 6/8
Immigration can't fix this. Professor Fernández-Villaverde explains that 'most immigrants worsen the fiscal position of the government' and only the top fraction of immigrants are net payers.
And globally, every country's gain is another country's loss. 7/8
What does Fernández-Villaverde recommend for solutions? Here his presentation is thin. He suggests cheaper housing but emphasizes that urban housing is 'deeply antifamily'. Education needs to be reformed.
He promises more in the coming days in terms of policy ideas. 8/8
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