By Michael F. Duggan
As of yesterday, the world’s population is estimated to be eight billion. It took around 200,000 years for humans to hit the one billion mark. We went from seven billion to eight billion in about a decade.
Although estimates of an ideal sustainable world population vary, the biologist Paul R. Ehrlich puts the number at 1.5 billion – 2 billion. The philosopher, John Gray, puts it at between .5 and 1 billion.1
Note
1. John Gray, Straw Dogs, 11.