(a) Acres needed to feed a person at US dietary standards = 1.2 (= 0.49 hectares)
(b) # of people = 6.5 billions
(c) Land needed to feed them = (a) * (b) = 31.5 million sq km
(d) Land available = 74 million sq km (from Wikipedia = half of the planet’s “dry” land area)
—-> “Current occupation index” = (c) / (d) = 42.4%
In other words, even if all humans were fed according to US dietary standards, there would be space for 15 billion people.
Even by being very conservative on the figures, it is hard to imagine why the planet would not be able to feed 10 or 12 billion humans.
Interestingly, in an article published in Nature (“The end of world population growth” Nature 412, 543-545, August 2001), Lutz et al. forecast a maximum of 8 billion people, around 2075.
And I haven’t even mentioned likely, incremental agricultural improvements.
Planet-wide Overpopulation, then? Not at all.
And there goes another myth of contemporary catastrophism…