I see a quote where the estimated possible population is basically derived directly from the land area required for habitation alone which is rubbish.

We need to account for resource use as in food, energy, fertilizer, freshwater etc.

I hope you'll feel refreshed to hear about a different resource peak than the usual, here's about limited phosphorus for fertilizer: http://phys.org/news/2013-04-phosphorus-essential-lifeare.ht...