Why Did People Start to Have Shorter Lives After the Flood?

Dear AiG:

In A Life Sentence?, you stated that God was not giving men a lifespan, but rather he was giving men one hundred and twenty years to repent.

Now, I too am a Christian but I must ask one question: if God was not setting man's lifespan, then why is it that after the flood men started living for a shorter and shorter time? It would appear that men were gradually getting to be 120 years old. If this is not the result of God giving them a possible lifespan, then what is it the result of? Why did men gradually live younger?

And yet if it is indeed the result of God's judgment, then why do some people live past the age of 120? ICR did an article on a woman who claims to be 157 years old, and official documents would place her at at least 135 years old.

So, in a nutshell, why did men gradually get younger after the flood? I'd appreciate your response. Thanks.

—J.W., U.S.

It is a pleasure to hear from you. I always enjoy the questions that make us get into the Word in more detail. It is actually exciting.

In A Life Sentence?, you stated that God was not giving men a lifespan, but rather he was giving men one hundred and twenty years to repent.

Now, I too am a Christian but I must ask one question: if God was not setting man's lifespan, then why is it that after the flood men started living for a shorter and shorter time? It would appear that men were gradually getting to be 120 years old. If this is not the result of God giving them a possible lifespan, then what is it the result of? Why did men gradually live younger?

Remember that just because men began to live shorter lives does not prove that God set a limit on man’s life span. The fact is that they were still well over 120 years until the time of Moses. So, God would have been wrong had this declaration been about the 120 year life spans.

The 120 years is the countdown to the Flood. Please see the timeline in “How Long Did It Take for Noah to Build the Ark?”

And yet if it is indeed the result of God's judgment, then why do some people live past the age of 120? ICR did an article on a woman who claims to be 157 years old, and official documents would place her at at least 135 years old.

Since this is not in reference to living over 120 years, then this is acceptable. In fact, this is a good article to read by our friends at ICR.

So, in a nutshell, why did men gradually get younger after the flood? I'd appreciate your response. Thanks.

This, though, is really the crux of the issue here. The ages did drop off over the next millennium or so. Several people have proposed ideas as to why this happened.

Diet

For example, some thought it had to do with diet. People were first permitted to eat meat after the Flood (Genesis 9:3), so some scholars thought the original vegetarian diet (Genesis 1:29) would have helped people live to such great ages. Some have further pointed toward Daniel and his request of a vegetarian diet (Daniel 1:8–16).

However, vegetarian diets never allowed people to live to such ages as 900 years even today. In fact, there’s little evidence that vegetarians attain a life span much different than those who retain meat in the diet.

Increased Oxygen

Some have proposed that increased oxygen levels prior to the Flood (which changed significantly after the Flood) would allow the body to better heal and eliminate disease. And although there are some benefits to a temporary increase in oxygen in some cases (e.g., hyperbaric medicine), in other cases it is detrimental to your health (e.g., birth defects such as blindness in children due to supplemental oxygen, oxygen toxicity, swelling of lenses in the eye causing blurred vision, etc.).

Increased oxygen levels can cause a host of other problems because oxygen is extremely reactive, causing oxidation where your body doesn’t want it. People often eat foods that are high in antioxidants to reduce these extra “free radicals” of oxygen. Regardless, the simple fact is that such experiments have not permitted people to live to ages remotely close to 900 years.

Environmental Changes

The world changed significantly due to the Flood. Vegetation, as well as land and sea life, were drastically reduced and made to virtually “start all over again.” But did this cause aging to significantly drop off?

Noah, who was already 600 years old, stepped off the Ark into this new world as well. If the environment was the cause of the reduced age, why did Noah live 350 more years? Noah was the third longest lived person recorded in the Bible (after Methuselah and Jared)! If the environmental effects were the cause, then this does not make sense—unless these environmental effects were more gradual. This is not to say environmental changes had no impact, but those effects were not the primary cause of life spans dropping about nine times.

Genetics

In fact, genetics were likely the primary culprit. Dr. David Menton and Dr. Georgia Purdom look specifically at genetics and resulting functions of anatomical features with regards to aging in “Ancient Biblical Lifespans: Did Adam Live Over 900 Years?” from the New Answers Book 2:

We need to keep in mind that there were two major genetic bottlenecks:

1. At the Flood
2. At the Tower of Babel

Flood Bottleneck

Genetic bottlenecks cause a significant loss of access to other people’s versions of genes (called alleles) that are essentially lost. The obvious loss of pre-Flood people reduced the alleles in the gene pool in humanity to only eight people, but really only six. Scripture reveals that Noah and his wife had no more sons after the Flood (Genesis 10). So, this leaves Shem, Ham, and Japheth and their wives, and, of course, these three men each inherited their genes from the same two parents.

So, early generations after the Flood, like early generations after the Garden of Eden, saw marriages between people who were close relatives. Of course, such close intermarriage was not forbidden until the time of Moses (See “Cain’s Wife”). Regardless, this bottleneck saw the loss of a great many alleles from the gene pool of those who died in the Flood.

Tower Bottleneck

If you look at the ages of people born after the Flood, the ages do a sudden drop but are stabilized at about 450 years or so:

So, the ages seem to drop significantly, where Shem, who was born prior to Flood, lived to 600. After the Tower, ages suddenly drop from about 450 to about 235 or so for three generations:

Even two generations after this, Terah lived to only 205. But age limits trickle down from there.

Genetic Bottleneck Conclusion

So the Flood and the Tower bottlenecks did something significant to cause ages to drop. In both cases, there is a loss or splitting up of the gene pool. Consider also how mutations can affect age with an extreme example: “One Tiny Flaw, and 50 Years Lost!”

With these bottlenecks, a host of alleles would have been filtered out and lost. For example, immune systems may not be as good, resulting in more infectious disease.

Shem: An Intriguing Clue

Another interesting clue comes from Shem. The bottleneck at the Flood would not have affected Noah, as his genetics were not bound by that event. And he lived 350 years after the Flood and died at 950 years.

Ham and Japheth’s ages are not recorded in Scripture. But Shem was 600 years when he died. Either of the above bottlenecks, the Flood or the Tower, would not have affected Shem’s longevity.

And yet, his age was significantly reduced from his father’s. The Bible does not record the cause of death; so, it is possible that something caused a premature death. However, it seems likely that he died of old age. And this is a clue that there may have been a genetic problem that passed through Noah to Shem (and perhaps Ham and Japheth, too) to trigger a drop in ages.

It is possible that there was a genetic mistake hidden within Lamech.

Lamech, Noah’s father, only lived to 777. In the reality of his day, he was young pup! Methuselah, Lamech’s father, lived nearly 200 years longer than Lamech! So, it is possible that there was a genetic mistake hidden within Lamech that occurred between Methuselah and his son Lamech.

If this defective gene had been passed to Noah from Lamech, and yet masked by a good gene from Noah’s mother, it may not have affected him, and, hence, he still lived to a ripe old age of 950 years. But Noah could still pass this defect along to his sons, such as Shem, who lived to 600 years. But why couldn’t this have been masked by a good gene from Noah’s mother . . . unless she too had this defective gene?

After the Flood in Genesis 9 (prior to the assembly at Babel while Noah and his descendants were still living in tents west from Shinar), righteous Noah became rather drunk—so drunk in fact, that he lay naked in his tent and failed to recognize that his son Ham had gazed into the tent and observed him and then proceeded to spread the word about his father (Genesis 9:21–22).

So, it was Shem and Japheth’s responsibility to walk in backwards, not looking at their father’s nakedness, and lay a covering over him (Genesis 9:23). Why was it their responsibility to cover Noah? Where was Noah’s wife? According to Archbishop Ussher, the events at Babel occurred about 106 years after the Flood (according to the Bible about 3–4 generations had been born, so this makes sense.)1 Thus, this event occurred before Babel, but enough time for Canaan to be born (Ham’s youngest) and be cursed by Noah when he awoke.2

If this were the case, then Noah and Mrs. Noah could have had defective genes that were passed to their sons and this could explain why Shem only lived to 600 years, why Noah’s wife is missing in Genesis 9, and why ages began dropping. Further, this explains one aspect of how this could have coupled in subsequent generations to drop the ages even further. But, of course, this is biblical speculation.

Common Denominator of All People Today

All people today go back to Noah and his wife (Mrs. Noah). So, the genetics of reduced age has to come through them. Consider the name of Noah and the prophecy associated with it:

Genesis 5:29
And he called his name Noah, saying, “This one will comfort us concerning our work and the toil of our hands, because of the ground which the Lord has cursed.”

Noah’s name literally means “rest.” This verse is obviously looking back to Genesis 3:17–19, where the “ground was cursed” due to sin (“by the sweat of your brow” and “through painful toil will you work” the ground).

How can we have rest or comfort in this? It is by either better ways to doing the work . . . or not doing it as long. Commentators have long stated many ideas on this, such as Noah comforting us in being a type of Christ with the Ark. Others have pointed out that this relates to the post-Flood statement by God that He would no longer curse the ground due to man’s sake, among other comments too.

Some have said that this was the advent of farming; however, Adam worked the ground (Genesis 3:23) and so did Cain (Genesis 4:2–3). So, this may not be the best interpretation. Consider this verse:

Revelation 14:13
Then I heard a voice from heaven saying to me, “Write: ‘Blessed are the dead who die in the Lord from now on.’” “Yes,” says the Spirit, that they may rest from their labors, and their works follow them.”

This verse gives support to the idea that rest or comfort from work and labor means that you have died. Let’s face it: the people after Noah did not work for 900 years, but far less than that by the sheer fact that they did not live that long.

Could Genesis 5:29 mean that through Noah people would not live as long and therefore have rest concerning their work and toil? It is possible. I’m sure an entire book could be written on the subject, but I hope this response helps get you to think about the ages in more detail.

With kindness in Christ,
Bodie