[throwawaylinux]

> Taking that argument seriously it means that "the sustainable carrying capacity" is way below what we had in 300 BCE.

No it doesn't, because I'm not saying there's one carrying capacity that's somehow inherent to earth.

Of course it's related to technology and lifestyles and our environmental impact. What made you think I was trying to say otherwise?

Clearly if we got all our energy from burning wood and food from hunting and gathering, we couldn't even support 1% of our population without massive unsustainable habitat destruction. And yes in the past there have been many unsustainable societies that we might like to have changed but that's done now we are dealing with what's in front of us.

And with our current environmental impact, the current population is not sustainable. Maybe technology and societies will change enough in future that it could sustainably support today's levels of population, but that's irrelevant. That doesn't help the 53% of grassland birds in North America being wiped out in the past 50 years.