It’s a pretty well documented observation that the birth rate in prosperous nations tends to level out without intervention. Additionally, prosperous nations are responsible for orders of magnitude more per capita carbon emissions than the “global south.”

Is your plan to depopulate the wealthy countries responsible for CO2 emissions who already have a replacement level birthrate?

Or is it to artificially prevent population growth and economic development in undeveloped countries? It would be morally unacceptable for the global north to extract wealth from the global south for 500 years, use the wealth to build highly industrialized economies, then prevent the rest of the world from catching up economically.