the current population has grown, very rapidly, from something much smaller. The result is that, as a species, H. sapiens is extraordinarily samey. There is more genetic variation in a few troupes of wild chimpanzees than in the entire human population. Lack of genetic variation is never good for species survival.
Also from the article:
“Another reason for the downturn in population growth is economic. Politicians strive for relentless economic growth, but this is not sustainable in a world where resources are finite.” This one keeps coming up repeatedly.