Earth's Timeline - Heading

Population Estimates

Of course, we cannot know the exact population of the earth throughout time, but we can make some calculated estimates based on what we do know. When we do this we arrive at the following estimates:

World Population at the Flood in 4990 BC: 900,000 - 2 Million
World Population at the Tower of Babel in 3100 BC: 1.0 - 1.5 Million
Israelite Population at the Exodus in 1447 BC: 1.5 Million

Let's examine how we can develop the above estimates…

Israelites at the Exodus: 1.5 Million

We know that there were 603,550 males aged 20 years or older that left Egypt in the Exodus of 1447 BC
 (Exodus 38:26). We could expect that there was roughly the same number of females aged 20 years or older. As of 2006, the worldwide male-female ratio was 1.01, meaning that there were 101 males for every 100 females.1 That is essentially a 50/50 split. Assuming the same number of females, we can estimate the population of Israelites aged 20 years and older to be 1,207,100 in 1447 BC. 

Now we need to estimate the number of Israelites aged under 20 years that left Egypt. The average person lived longer in 1447 BC than today. Today's worldwide average life expectancy is 65 years. We don't know what the average was in 1447 BC, but we do know the death ages of the following individuals who were alive in 1447 BC:
Joshua 110 years Joshua 24:29
Moses 120 years Deuteronomy 34:7
Aaron 123 years Numbers 33:39

The average of their three death ages is 117.7 years, which is 1.8 times longer than today's life expectancy. The Bible helps us determine if it is reasonable to conclude that the average life was 117 years in length in 1447 BC. The book of Psalm was written around 1000 BC and we read that at that time the average person lived about 70 to 80 years:
"The days of our years are threescore years and ten; and if by reason of strength they be fourscore years, yet is their strength labour and sorrow; for it is soon cut off, and we fly away." (Psalm 90:10)
David lived during this time when the average life was 70 to 80 years. When he was 66 years old, just a few years short of the 70-to-80-year life expectancy, God said He was old and stricken in years:
"Now king David was old and stricken in years; and they covered him with clothes, but he gat no heat." (1 Kings 1:1)
If we go back 400 years earlier to the Exodus we will find that the average life was longer then. Joshua lived during the Exodus and when he was 110 years old God said He was old and stricken in years:
"Now Joshua was old and stricken in years; and the LORD said unto him, Thou art old and stricken in years, and there remaineth yet very much land to be possessed." (Joshua 13:1)
Therefore, our life expectancy estimate of 117 years in 1447 BC appears to be reasonable as it is just a few years longer than Joshua's age of 110 years when God described him as old and stricken in years. This parallels God's description of David when he was just a few years short of the average in his day.

Currently, 36.0% of the world's population is under the age of 20.2 However, since people lived longer in 1447 BC, those under the age of 20 would represent a smaller percentage of the overall population. There are a couple of different equations we could use to determine what percentage of the population in 1447 BC would be under the age of 20 based on the information we have. Depending on which way we calculate it, we will arrive at an estimate of 18% to 22%. We will take the average and estimate that 20% of the Israelites in 1447 BC were under the age of 20. We have already estimated that 1,207,100 Israelites aged 20 years or older left Egypt. If that represented 80% of the population (assuming 20% of the population was under 20 years old), then the whole population including children would have been about 1,508,875. 

We can check if our conclusion is logical by calculating the growth rate based on our estimated population. We know that all of the Israelites were descendants of Jacob. Remember, Jacob was renamed Israel:
"And he said, Thy name shall be called no more Jacob, but Israel: for as a prince hast thou power with God and with men, and hast prevailed." (Genesis 32:28)
We've established that Jacob was born in 2007 BC and the Exodus occurred in 1447 BC. Therefore, the Israelite population went from 2 people (Jacob and his wife) to about 1.5 million in 560 years. To calculate the growth rate, we use the following equation where x is the growth rate:

Equation for Calculating Growth Rate

When we perform this calculation we arrive at a growth rate of 2.4%. The average worldwide growth rate over the last 100 years has been 1.7%.3 A positive growth rate occurs when births outnumber deaths. Since the average person lived longer in 1447 BC and had more children than today (Jacob had twelve sons for example – Genesis 35:22), it makes since that the growth rate in 1447 BC would be a little higher than today. Therefore, a growth rate of 2.4% is reasonable compared to today's rate. The fact that our calculated growth rate of 2.4% is logical helps us feel confident we have arrived at a relatively accurate estimate of the Israelite population in 1447 BC.

World Population at the Flood: 900,000 – 2.0 million

The Flood occurred 6,023 years after Creation in 4990 BC. Based on the information we are given in the Bible, we can know that the life expectancy of man did not change over the 6,000 years between Creation and the Flood. Adam lived to be 930 years old and Methuselah, who lived 5,000 years later, was 969 years old when he died. In fact, when we take the average of all the death ages given to us in the Bible between Creation and the Flood we learn that the average life expectancy was 907 years. This means that there were 6.6 lifetimes between Creation and the Flood. We calculate this by taking the 6,023 years that passed between Creation and the Flood, and then divide it by the average life of 907 years.

It is important to note that, even though people lived to be about 900 years old before the Flood, the average family size was not any larger than it was after the Flood. In other words, longer lives did not result in people having more children. 

We are going to use the information we discovered in our examination of the Israelite population to help us here. We determined that the life expectancy in 1447 BC was probably about 117 years so 6.6 lifetimes at that point in time was about 772 years. Since family sizes were similar before and after the Flood, we would expect that the world population after 6,023 years before the Flood to be similar to what the Israelite population would be 772 years after 2000 BC. Both spans of time represent 6.6 lifetimes in their respective points on the timeline of history. However, the world population before the Flood was very wicked. The Israelite population was likely less violent among themselves and so we should expect that the growth rate before the Flood would have been more negatively affected by violence than the growth rate of the Israelites. Therefore, we shouldn't use the 2.4% we calculated as the growth rate for the Israelites. Instead, we will use the growth rate the world has experienced in the last 100 years: 1.7%. Again, we will use our growth rate equation:

Equation for Calculating Growth RAte

In the equation, we will use 1.7% as our growth rate x, 2 as our beginning population (Adam and Eve), and 772 as the years for which we are calculating growth. Remember, 772 years in 1447 BC would be 6.6 lifetimes, the equivalent to the time from Creation to the Flood based on life expectancies. When we do the algebra we calculate an "ending population" of about 900,000. 

This is, of course, just an estimate. We cannot be as certain of its accuracy as we can of our estimation of the Israelite population. Even though our calculations yielded a population of 900,000 at the Flood, altering our estimated growth rate could yield a population as high as 2 million. The real benefit of this exercise is discovering that the population was still relatively small 6,023 years after Creation.

World Population at Tower of Babel: 1.0 – 1.5 million

If we take the average of the death ages that are given to us for individuals that lived between the Flood and the Tower of Babel we can estimate that the average person lived 445 years. The Flood occurred in 4990 BC and in that year the world's population was reduced to just eight people (2 Peter 2:5).  We have determined that the Tower of Babel was built around 3100 BC. Therefore, 1,890 years passed between the Flood and the construction of the Tower of Babel. If each person lived an average of 445 years, then 1,890 years is about 4.3 lifetimes (1,890 / 445 = 4.3). 

As we did with determining the world population at the Flood, we will use the information we gathered from the Israelite population to help us here. Since we are examining a timeframe of 4.3 lifetimes between the Flood and Tower of Babel, we need to examine the equivalent amount of time from the Israelite population. We estimated that the average person lived 117 years in the Israelite population in Egypt so 4.3 lifetimes would be 503 years (117 x 4.3 = 503). 

Using our population growth equation, we will input 8 as the beginning population, 503 as the number of years, and 2.4% as the growth rate that we found in the Israelite population. We used a lower growth rate before the Flood because of the violence in the world at the time, but the Bible tells us the people were unified before the Tower of Babel so we can assume people were less violent among themselves than before the Flood. When we use these figures, we arrive at an estimated world population 1.2 million when the Tower of Babel was constructed.

Allowing for some fluctuation in the growth rate we could estimate that the actual world population before the Tower of Babel was between 1.0 and 1.5 million. The US Census Bureau estimates that the population in 3000 BC was 14 million4 but that calculation is based on two inaccurate assumptions. First, they assume that mankind has been around longer than he has. Second, they do not factor into their calculations that the population was reduced to just eight people in 4990 BC because everyone else was destroyed in the Flood.

Why Is This Information Useful?

We have had to use estimated figures in our calculations. As a result, we have to keep in mind that our conclusions are also estimates. The point of this exercise is to shed some light on how small the population was before 3100 BC. 

The fact that there were only one or two million people at the time of the Flood is interesting when we consider that Noah spent 120 years building the ark. That is ample time for such a small population to be fully aware of his actions and likely be aware of God's warning that destruction was coming. 

Likewise, we can more readily understand the statement in the Bible that the people were unified in the construction of the Tower of Babel because the whole world's population was about the size of San Diego, CA. It makes sense that most of such a small population would stick relatively close together in a single civilization.

Another interesting fact these calculations reveal is that it probably took over 8,000 years before the worldwide population exceeded 3 million. 

Also, knowing that about 1.5 million Israelites left Egypt paints a picture of just how massive the parting of the Red Sea had to be. A narrow road-width parting would not have been sufficient for 1.5 million people and all their cattle to cross in any kind of timely manner.

World Population Throughout History

Using the information we have calculated and combining it with data from Census Bureau for 1000 BC to present day, we arrive at the following graph of the world's population throughout history:

Graph of World Population over time

This is at least very thought-provoking, if not alarming.