Any increase in size is coming from deforestation, which is devastating to our planet. [2]
[1] https://ourworldindata.org/land-use
[2] https://education.nationalgeographic.org/resource/deforestat...
You are discounting civilizations ability to adapt and invent by an absolutely incredible margin that is not supported by our own history of human events.
The distribution of resources in the world is grossly unfair and it is not sustainable that 8 billion people live the way Americans live.
As it stands now the world is already becoming a pollution infested shithole. Imagine what happens when 7 billion more people live like us.
For every rich and wasteful person in the world there is a poor person that lives in scarcity and „offsets“ the wasteful lifestyle. So we’re kind of at a limit when you want to make a genuine effort to continue fighting poverty.