Galeano, in the introduction to his Open veins of latin america, states that the only reason south america isn't as densely populated as Europe, is intentional underdevelopment, and colonialism. The European powers intentionally depopulated the indigenous of many of these countries by turning their economies into mono-crop / mono-mineral mercantile export ones from the 1500s onward.
I'm sure someone has tried to figure out earth's carrying capacity, but we're not even remotely close to it. There isn't even any vital resource whose production doesn't scale with population growth.
The fear-mongering about population growth is really only coming from euro-amerikkkan capitalists and white supremacists like Bill gates, who are mirroring their 1800s counterparts with population control attempts in places like Africa. Bill Gates openly says he's trying to stop "population increase in places we don't want it", showing his fear of the growth of potentially threatening non-white populations.
I recently learned that of the reasons for this neocolonial population control is to make sure that over-exploited regions don't become problematic once their natural resources are fully extracted.
Over-exploited countries are essentially forced to be dependent on the US for food. They pay for that food with some of the money generated via resource extraction. They have no agriculture of their own beyond cash crops like cocoa or coffee, which obviously cannot feed people. So once those resources are gone, the money to import food is gone, and these countries will have to experience some pretty serious population reduction before local agriculture can sustain the remaining population.
It's not just individual malthusian billionaires peddling this either, this has been official World Bank and IMF policy since the seventies at least.
