Biblical longevity

Biblical longevity refers to the claimed biologically-impossible life spans of some Biblical characters, which were often hundreds of years long. Some characters in the Bible simply live too long (in terms of hundreds of years ) despite God's command after the flood which puts an upper bound on human life at 120 years. This divine decree is a problem for many literal interpretations of the Bible, not least because lived to be 122, but also because some Biblical characters subvert the decree, leading to quite hefty contradiction in scripture.

The scriptures
After God has seen how wicked humanity is, He decrees an upper limit to the age of humans after the flood.
 * 

If this statement is true, we should not expect anyone to have a life longer than 120 years after the flood. However, in later passages of the Bible, there are people who blatantly defy this command and live far more than 120 years.

Examples

 * Abraham lived to the ripe, old age of 175 years old (with the physical prowess to father a child at 100 years of age, no less!)
 * Sarah, Abraham's wife, had her numbers come up at a comparatively low 127 years of age (though she did give birth to Abraham's child when she was 90 years old!)
 * Noah lived for 950 years (That's longer than Adam!)
 * It's 350 years even if you don't count the years he lived before the flood.
 * Although the rule might not have been retroactively applied (he might have been grandfathered).
 * Methuselah, of course, is famous for living longer than any other person mentioned in the Bible (given that women's ages weren't mentioned), reaching the age of 969. However, his longevity wasn't as remarkable as it's often made out to be, since many others (including Noah, as mentioned) are said to have lived well into their 900s.
 * Shem lived for something like 600 years, so he pretty much got grandfathered in as well.
 * It's not clear why Japheth is not grandfathered in as well (Ham probably did not get grandfathered in due to the Curse of Ham).
 * Pretty much every one of Shem's firstborn descendants (all the way to Jacob! )
 * Moses's father, Amram, lived for 137 years and Moses' grandfather, Kohath, lived for 133 years. Moses himself reached the 120 years (he led the Exodus when he was 80, with the travel towards the Promised Land lasting 40 years).

Possible explanations
Far and way the most likely explanation is that it simply didn't happen and it's just a story.

However, those looking for other explanations have suggested:


 * Some suggested that free will enables an individual to defy God's commands, and the reduction of human lifespan is no exception.
 * Sin and sinful lifestyles cause aging and we were originally meant to live forever. This doesn't stand up to statistical analysis. Was Methuselah less sinful than Moses?
 * An environment change that gradually lowered the life span. This might have had something to do with the Great Flood, according to Answers in Genesis. All the water hanging around in the Firmament prior to the Great Flood might have been involved? Although there is no obvious mechanism for this to prolong lives. This is getting very desperate. It remains unclear how the discontinuities of life span between the descendants of Jacob and the ancestors of Moses are allowed unchecked.
 * By "year" the Bible actually means "month", although this is contradicted by the times the Bible uses days, months, and years together.
 * Verse By Verse International believes people just are taking Genesis 6:3 out of context and claims it really says that Big G was planning to flood the earth in 120 years. It certainly resolves the contradiction, but you also gotta wonder — why the wait?
 * Records on the naturalistic explanations for the difference in life expectancy were eaten by the goats, and the Bible is patched subsequently to accommodate that.
 * The Bible is not an accurate source concerning human longevity.