Project Genesis

Noah, Tower of Babel, & Population Growth

Question: It is explained that Noah lived through 2 generations, the floods generation and the tower of babel. At the risk of sounding disrespectful where did the other people come from if everyone perished in the flood? Or were people of floods generation non Jews and Noah happened to live among them and only that nation was destroyed? Meaning that there would have been other Jews living elsewhere because the Ark might have landed at a different part of the world after the flood, that is where the he came in contact with other people.

Answer: That is a very interesting question, which forced me (much to my delight) to research population growth rates and how to calculate them. Jewish tradition does believe that only Noah and the others with him were saved from the flood; no one else in the world survived. So how were there so many people when the tower was built? Here are the results of my research:

Noah lived a very long time—950 years total. The flood occurred when Noah was 600 years old—in the year 1656 since creation, and Noah and the others left the ark the next year—1657 since creation. The incident known as the Tower of Babel took place when Noah was 940 years old—in the year 1996 since creation.

This means that there were 339 years between when Noah and the others left the ark and when the Tower of Babel was built.

The Torah notes that there were (at least) 8 people in the ark: Noah, his wife, his 3 sons, and the sons wives.

The next important piece of information we need is the average growth rate during those 339 years. Of course, we have no hard data on that. Worldwide, the average growth rate today is 1.14%. However, smaller countries have growth rates as high as 5%. I think its fairly safe to assume that with such a small starting population (only 8 survivors of the flood), the growth rate was on the higher side. Remember that birth control was not quite in vogue then. So I think a 3.5% growth rate is a safe assumption.

Next, we need the formula to calculate growth based on initial population (P), growth rate®, and number of years (Y). That formula is:

((1+R) ^ Y) * P

Plugging in our values:

((1 + .035) ^ 339) * 8

This yields a population at the time of the Tower of Babel of over 920,000 people! So even assuming everyone else in the world was destroyed save those 8 people in the ark, the world would have been quite populated by the time of the building of the Tower of Babel.

Even if we assume a smaller population growth rate, say 2.5%—which would be a very conservative number given such a small starting population—again, using our formula:

((1 + .025) ^ 339) * 8

yields a much smaller population of 35,000 people, but still not insignificant.

So, it does seem that the years between the flood and the building of the tower left plenty of time to populate the world.

As an aside, this also points out the power of compound interest rate growth.

Thanks for the opportunity to do some fascinating research. If you have any follow up questions, please feel free to respond.

Be well,
Rabbi Yoel Spotts

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