On the contrary, economic growth is closely coupled with population growth.
Above replacement birth rates are a necessity for economic growth.
Replacement birth rates lead to economic stagnation.
Below replacement birth rates lead to economic contraction.
Read up on demographics and their effects on economics, then get back to me.
Our nations last great decades long economic boom did not correlate to an increased birth rate, but with lower taxes.
Overall the human population of the Earth is increasing. It is not at all declining.
To think the gravest threat to humanity is declining birth rates is delusional.
There was, is and will be a ready supply of humanity ready to fill in the gap of those populations that decline to reproduce at a replacement rate. More a threat to their particular way of life than a threat to “humanity” - but once again that isn't the argument the author is making.