The exponential function works both ways :) The Chinees government, which, unlike the West, is mainly run by people with a sound engineering background, understood this well. I still remember the China of 1970s'...and just look where they are today.

At an economical still safe reproduction rate of 1,6 instead of the replacement value of 2,1 will bring a country's population back to the region's carrying capacity within a century or even less. My children's children could be safe and living in abundance....if we wanted it. But we don't. Anyhow, I walk the talk. It's the least, and perhaps the only thing I can effectively do.