Farming and population density

From Harvesting the Biosphere:

Half a million years ago, there were between 15,000 - 125,000 people, total. Today there are about 8bn. What changed? How we farm.

Human population Density (People/km^2)
min max
Foraging 0.01 1
Pastoralism 1 2
Shifting Cultivation 20 30
Traditional Farming 100 400
Modern Farming 400 1400
Smil, 2013. Note: all densities for foragers and pastoralists are per unit of exploited land; all densities for traditional and modern agriculture are per unit of arable land.

Related: fundamental needs.