The Guardian: America's premier pronatalists on having 'tons of kids' to save the world: 'There are going to be count...

[OKIsItJustMe]

10. In past ages, people had lots of children, because many of them would not survive to adulthood

When parents are confident their children will survive to reproduce, they have fewer children.

India emits less greenhouse gas than the United States, in spite of a larger population, because, the “average Indian” produces less greenhouse gas than the “average American.”

https://ourworldindata.org/grapher/per-capita-ghg-emissions

Population certainly is a problem, however the profligate use of energy may be the more serious threat.