From Eight to Eight Billion in Just a Few Thousand Years?

Could humanity have grown from eight individuals to eight billion in only about 4,500 years, as the Book of Genesis appears to suggest?

One of the criticisms raised by evolutionists against the biblical account of a recent creation and a global flood concerns population growth. Today, the world population exceeds eight billion, a figure said to have been reached over a period of 200,000 to 300,000 years. According to the Bible, however, only eight people survived the flood: Noah, his wife, their three sons, and their sons’ wives. Biblical chronology places the flood around 2350 BC, with Bishop Ussher dating it to 2348 BC.¹

This allows for roughly 4,370 years for the population to increase from eight people to over eight billion. Evolutionary theory, on the other hand, maintains that Homo sapiens emerged between 200,000 and 300,000 years ago, requiring that span to reach the current population. Another view claims that after the Toba volcanic catastrophe, humanity recovered over approximately 75,000 years, beginning with an estimated 1,000 to 10,000 survivors.² Yet to grow from eight individuals to billions in less than four and a half millennia may appear entirely unrealistic.

The mathematical perspective

James J. S. Johnson, a professor at the Institute for Creation Research, carried out basic demographic calculations.³ He began by assuming an average generational length of either 25 or 33⅓ years. Over approximately 4,500 years, this would result in 180 or 135 generations, respectively. He then applied a historical average replacement rate of 1.2.

Beginning with six individuals (excluding Noah and his wife, due to their advanced age) around 2500 BC, and using a 25-year generational average, the 180th generation would produce 1,073,434,474,371,002 people. With a 33⅓-year average, the 135th generation would produce 293,507,678,118. Recognising that the initial replacement rate was significantly overestimated, Johnson reduced it to 1.15. This adjustment resulted in totals of 505,548,136,684 and 938,338,851, respectively. While the former remains too high and the latter already too low, these figures demonstrate that the expansion of humanity from eight individuals to eight billion over 4,500 years is indeed plausible.

Humanity’s demographic history according to modern science

Johnson’s calculations are, of course, very rudimentary. They simply show that such population growth is mathematically feasible. Humanity’s demographic history, however, is much more complex, featuring stagnation and even periods of depopulation. Currently, there are over 8 billion people, but in 1930, the global population was just 2 billion. Around 1800, it was 1 billion, and around 1500, it was 500 million. Around the year 1000, estimates range from 250 million to 350 million. In AD 1, the population was between 170 million and 400 million.⁴ This demonstrates a significant stagnation during late antiquity and the early Middle Ages.

Going back to 2000 BC, estimates suggest the global population was between 27 million and 100 million. The Bible states that Noah’s flood took place only a few centuries earlier. Assuming Ussher’s chronology, about 350 years had passed. Could the population have increased from eight people to around 80 million in just 350 years?

High mortality of prehistoric humans

First, it is important to note that, according to evolutionary theory, humans developed in a harsh natural environment, which required constant struggle for survival. The Encyclopaedia of Population (2003) states that the average lifespan of prehistoric humans was between 20 and 35 years.⁵ This low average is largely attributed to high rates of infant and child mortality.⁶ However, those who reached adulthood typically lived to the age of 60 or 70, and in some cases even 80.⁷⁻⁸

Despite this, the generally high mortality rate among prehistoric populations contributed to long-term stagnation in demographic growth. According to some demographers, between 10,000 and 4,000 BC—a period of 6,000 years—the global population remained at only a few million.⁹ Likewise, over what are believed to be tens or even hundreds of thousands of years, Homo sapiens are thought to have remained few in number, with extremely slow growth punctuated by periods of decline. This historical pattern of limited growth underpins much of the scepticism among evolutionary demographers regarding the biblical account of rapid population expansion.

Demographic calculations based on Genesis 11

The Bible, however, presents the centuries after Noah’s flood as highly unusual. His descendants from the first four generations are said to have lived for more than 400 years. Shem reportedly lived to the age of 600, and Noah himself to the age of 950. In the generations following Heber, lifespans dropped to just over 200 years. Abraham, the tenth generation after Noah, lived to be 175. His son Isaac reached 180 years of age, and later descendants lived even shorter lives. This suggests that the early post-Flood generations were in exceptionally good health and likely did not experience high child mortality, unlike those who followed.¹⁰

Further calculations can be made based on this information. The Book of Genesis implies that the typical age of reproduction at that time was about 30. Suppose that each generation from Shem to Terah, Abraham’s father, produced one child every three years. This would result in an average of ten children per family, assuming that parents stopped having children once their grandchildren were born. Based on these assumptions, calculations show that the population could have grown from eight people to 439,452,396 in just 350 years, for example from 2350 to 2000 BC. To reach a population of 80 million, a little over 300 years would have been enough.

Conclusion

In other words, the growth of the world population from eight to eighty million within 350 years, from Shem to Abraham, is entirely possible given specific assumptions. For this reason, the demographic arguments used by evolutionists against the idea of a biblical flood have no valid foundation.

By the way, we recommend reading the articles:

• Extrabiblical Testimonies of the Flood
• Did Moses Invent the Alphabet?
• Giants in the Bible and Other Writings
• Was Jesus Christ a Historical Figure?
• The Quipu: Knotted Strings That Testify to Ancient Intelligence

Footnotes

1. Wright, D. (2012) Timeline of the Flood. Answers in Genesis. Available at: https://answersingenesis.org/bible-timeline/timeline-for-the-flood/
2. Osipov, S. et al. (2021) ‘The Toba supervolcano eruption caused severe tropical stratospheric ozone depletion’, Communications Earth & Environment, 2(71), April 12. Available at: https://www.nature.com/articles/s43247-021-00141-7
3. Johnson, J.S.J. (2023) ‘Post-Flood Repopulation: From 8 to 8,000,000,000!’, Institute for Creation Research. Available at: https://www.icr.org/article/post-flood-repopulation-from-8-8000000000/
4. United States Census Bureau (n.d.) World Historical Population. Available at: https://web.archive.org/web/20061231163421/http://www.census.gov/ipc/www/worldhis.html
5. Holloway, A. (2014) ‘The life expectancy myth, and why many ancient humans lived long healthy lives’, Ancient Origins, 24 April. Available at: https://www.ancient-origins.net/news-evolution-human-origins/life-expectancy-myth-and-why-many-ancient-humans-lived-long-077889
6. Many people believe in the so-called “life expectancy myth,” which claims our distant ancestors reached old age at only about 30 years. However, this is merely an average that accounts for high child mortality in historical times.
7. Ruggeri, A. (2018) ‘Do we really live longer than our ancestors?’, BBC Future, 3 October. Available at: https://www.bbc.com/future/article/20181002-how-long-did-ancient-people-live-life-span-versus-longevity
8. The Bible, New King James Version, 1982, Psalms 90:10.
9. See note 4.
10. The Bible, New King James Version, 1982, Genesis 11:10–32.

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