During the first great agricultural revolution (10,000 BC to 5,000 BC), when humans moved from being hunter-gatherers to farmers, settling in small villages and ultimately towns, the world human population is estimated to have increased from four million to five million. In the next 5,000 years, from 5,000 BC to the birth of Christ, the human population is thought to have increased from five million to 100 million. In this second 5,000-year period, the human population increased approximately 25 times whereas in the first 5,000-year period, the increase was marginal. The reason for this disparity is that the earlier five millennia of domestication were the most lethal years in human history.

Source: The Irish Times August 22, 2020 05:01 UTC