/ Overall human life expectancy?

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MG - on 16 Sep 2016
Taking all the humans who have ever died, what would be the average lifespan?
GrahamD - on 16 Sep 2016
In reply to MG:

For all the humans that have already died, zero.
1
sjminfife - on 16 Sep 2016
malk - on 16 Sep 2016
In reply to MG:

given that there are 15 dead for each living person and the life expectancy has only recently started increasing, the overall average would be pretty close to the pre-industrial figure whatever that is (~ 30-35?)
GrahamD - on 16 Sep 2016
In reply to malk:

Isn't that adult life expectancy ? IE it doesn't count infant mortality in the average.
MG - on 16 Sep 2016
In reply to malk:
> given that there are 15 dead for each living person

Are there? I thought there were more living than had died?

And is 30-35 the actual life-span for "healthy" environments - ie. Africa, rather than cold, infertile, Northern Europe?
Post edited at 11:34
MG - on 16 Sep 2016
In reply to sjminfife:

Thanks. Some TED talks are superb!
malk - on 16 Sep 2016
In reply to GrahamD:

life expectancy at birth (inc infant mortality) estimates are in that range: https://en.wikipedia.org/wiki/Life_expectancy
surprised that world life expectancy was still just 31 only 100 years ago..
malk - on 16 Sep 2016
In reply to MG:
> Are there? I thought there were more living than had died?

i'd also heard that somewhere, but didn't ring true so i did my research..
http://www.dailymail.co.uk/news/article-2097038/Are-really-people-alive-today-lived-Earth.html
(please don't judge me;)
Post edited at 12:17
edunn on 16 Sep 2016
In reply to MG:

How are you measuring average?
If median or mode, then you'll probably get some large skews from events like the plague, WW1 & WW2.
cb294 - on 16 Sep 2016
In reply to edunn:

Such events won´t even figure, as they killed humans all across the ages (or reasonably close to the long term average anyway). I am sure that the average is dominated by low life expectancy of newborns and young children. Once you made it past your teens you could reach your 80's or 90's even in medieval and earlier historic times. Interestingly, people tended to live shorter but had more offspring once they gave up their hunter/gatherer lifestyle and started agriculture!

CB
MG - on 16 Sep 2016
In reply to malk:

Thanks - interesting
captain paranoia - on 16 Sep 2016
In reply to MG:

> Are there? I thought there were more living than had died?

Depends who you're counting...

In the introduction of the book '2001: A Space Odyssey', (in 1968) Clarke says:

"Behind every man now alive stand thirty ghosts, for that is the ratio by which the dead outnumber the living".

http://www.goodreads.com/quotes/212808-behind-every-man-now-alive-stand-thirty-ghosts-for-that

I suspect he may have included all the hominidae...

I see the 'Population Reference Bureau' only counts homo sapiens sapiens (and estimates hss evolved 50kya, which seems a bit late to me; I recall 200-100kya as being the estimate for anatomically modern humans. Granted, the population numbers in those periods would be tiny...)
Bob Aitken - on 16 Sep 2016
In reply to cb294:

> I am sure that the average is dominated by low life expectancy of newborns and young children.

Absolutely. Even in Victorian Britain infant mortality ran at rates that we'd now find appalling. And another factor that we tend to gloss over is the apparent long practice of infanticide in many societies - killing of babies, if only by exposure, to 'weed out' the sick, the weak and the disabled, those judged to be of the 'wrong' gender in the current culture, or simply those that represented too big a demand on family resources at times of stress. I imagine it's hard to factor in those neonate deaths in any calculation of average life span over human history.
malk - on 16 Sep 2016
In reply to captain paranoia:

if we include Homo erectus then maybe we have outnumbered the stars in our galaxy?
summo on 16 Sep 2016
In reply to MG:

> Are there? I thought there were more living than had died?

I think 'more or less' (R4 maths / statistical programme) proved this urban myth was wrong a year or two ago.

summo on 16 Sep 2016
In reply to cb294:

> I am sure that the average is dominated by low life expectancy of newborns and young children. Once you made it past your teens you could reach your 80's or 90's even in medieval and earlier historic times.

yeah, my grand parents for example. One Granddad born in 1910 had 10 brothers and 2 sisters, most born before him. 3 never reached double figures, a few went early teens, the war got a couple more. The 5 that got past the 1930s and WW2, reached between 70 or 80. Which still gives a rough average of 30 to 35 years. Pretty grim thought really when I've already exceeded that age.
ads.ukclimbing.com
malk - on 16 Sep 2016
In reply to summo:

> I think 'more or less' (R4 maths / statistical programme) proved this urban myth was wrong a year or two ago.

daily mail ran it 2012;)

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