It is interesting that the per capita peak was in the 1960s.

(1) [OC] The world’s biggest polluters based on cumulative CO2 emissions : dataisbeautiful (reddit.com)

All of these countries, except China, peaked in the 1960s.

US Fertility Rate Chart

Not sure this is meaningful but the correlation is interesting and curious.

U.S. fertility rate chart
Coldstreams