Why did man live longer
BEFORE the Flood?

Why did man live longer BEFORE the Flood? One of the most intriguing facts in the Bible is the immense life spans of the Biblical patriarchs before and just after the flood. Adam lived 930 years, Methuselah the longest lived of the patriarchs lived 969 years. Noah lived 950 years. The average life span before the flood (ten generations) was 857 years. After it the average life span (for the ten generations from Shem to Abraham) was only 317 years! Many who refuse to believe in the Bible state that these extended life spans are nothing more than myths and legends.

There are many factors that could account for the shortening of the life spans after the great flood. The Bible states that it would not only destroy the land dwelling air breathing animals but it would also destroy the earth.

"And God said to Noah, 'The end of all flesh has come before Me, for the earth is filled with violence through them. And, behold, I will destroy them with the earth.'" (Genesis 6:13, Holy Bible in Its Original Order - A Faithful Version (HBFV))

"'And I will establish My covenant with you. Neither shall all flesh be cut off any more by the waters of a flood. Neither shall there any more be a flood to destroy the earth.'" (Genesis 9:11)

After this event occurred the earth was completely different than the earth before. There were widespread global differences. These would include changes in the climate and atmosphere, hydrologic cycle, geologic features, cosmic radiation reaching the earth, ozone concentration, ultra violet light, background radiation, genetics, diet, and a host of other changes. All these caused a rapid decline of the longevity of humanity.

The Jewish historian Flavius Josephus writes the following about this subject:

"Now when Noah had lived three hundred and fifty years after the Flood, and that all that time happily, he died, having lived the number of nine hundred and fifty years. But let no one, upon comparing the lives of the ancients with our lives, and with the few years which we now live, think that what we have said of them is false; or make the shortness of our lives at present an argument, that neither did they attain to so long a duration of life, for those ancients were beloved of God, and [lately] made by God himself; and because their food was then fitter for the prolongation of life, might well live so great a number of years: and besides, God afforded them a longer time of life on account of their virtue . . ." (Antiquities of the Jews, Book 1, Chapter 3)

If you take the points of the population in question and graph them you can see how close the actual decay rate or curve fits the exponential decay curve. This will yield an equation and a value that is called the coefficient of determination. This is a mathematical ratio that reveals how close your graph fits the exponential decay curve. This coefficient of determination will have a value between 0 and 1. If the coefficient is 1 this is considered a perfect match.

Many of the Old Testament patriarchs had extremely long life spans. After the flood the life spans decayed until a norm of about 70 years was reached. These life spans can be plotted and the decay curve calculated to see how close the actual decay curve is when compared to the mathematically perfect exponential decay curve, which has a coefficient of determination of 1. When we do this we can show that the ages stated in the Bible for how long they lived were true.

Note also in the below graph that the coefficient of determination (R2) is almost .89. This means that the decay rate of the patriarch's death after the flood was only 11% from being a perfect match. In other words, the decay rate for the patriarchal life spans that declined is very close to matching the exponential (natural) decay curve.

Longevity of Biblical Patriarchs after the Flood

Figure 2

It took 20 generations for a new equilibrium of 70 years of life to be reached. Notice the life span decline that started with Peleg!