Slightly off topic, but it's fascinating to me that we're not seeing any of the major effects of overpopulation that Harrison imagined despite having surpassed

Slightly off topic, but it's fascinating to me that we're not seeing any of the major effects of overpopulation that Harrison imagined despite having surpassed the numbers in his book. Maybe the Green Revolution? Or the realization that not everyone in the world has to live in New York City.