World Population from BC 400 – 2000

Above we see the human population graphed for the last 2,400 years. (?Originally from: Atlas of World Population History – Colin McEvedy?) What if instead of a population explosion for the last 600 years we had a population stasis – no growth whatsoever – what would that look like? How much overshoot would we now be experiencing compared to any given year? Or, perhaps, how would the population appear at the end of a normal person’s life expectancy of 70 years compared to when they were born? These are some questions I was asking myself this morning.

This afternoon I was talking to a couple of my 85-year-old friends and asked them, “Were there too many or too few people when you were born?” They said they had never thought about it, but the population seemed about right. Most people had jobs most of the time and no one actually starved. A quick computation from memory: In 1925 there were about 2 billion people on Earth and now in 2010 there are about 7 billion people. That means there are 3½ times as many people now as when my friends were born. That is a population explosion!

Let’s try a slightly different approach to show the growth using the chart above and assuming a 50-year life expectancy period for ease of using the chart. At the beginning date of 400 BC there were about 100 million people, and in 1600 there were 545 million, or roughly a growth of 445 million living people in 2000 years. That is a 4½ times growth in 2,000 years. That would be an increase of about 111,000 for each of the 20 hundred-year periods, or 1,110 per year world-wide. Or about 5½ million per 50-year lifetime. Or very roughly, 1% more people living when a middle-aged person died than when they were born, at any time during that very long 2000-year period. (Sorry that got messy!)

My old buddies were seeing 350% more people. Can that simple calculation be right? It is wildly beyond crazy speculation. That the number of people alive, at the end of a typical human lifetime, has gone from an nearly invisible 1% to people heaped everywhere, 350%. Okay, the age was changed from 50 years old at the end of life to 85 years old at the end.

Let me recalculate for someone 50 years old in the year 2000 so the base is the same. The population numbers go from 2,500 in 1950 to 5750 in 2000. Then dividing 5750/2500=2.3. Whew, only an increase to 230% in a 50-year lifetime.

But wait – all species must in the long run be in balance with their environment, and even back 2000 years ago people were doing quite well compared to other species at a sustained 1% growth rate. If we look at human population growth since our species developed all of our modern physical qualities visible in the archeological record, say 100,000 years ago, we would get a growth number well under 1%. Or perhaps defining human beings starting from when the first unequivocally symbolic artifacts were found, say 40,000 years ago with some art objects beyond a bored hole in a shell, it would still be well under 1% global change.

If the line between 500,000 and 10,000 were drawn to scale it would be 50 times longer and really flat. Various population experts show different population histories for the world, usually based on reasonable but general assumptions like the kind of economy people in a given area were using for their livelihood. From that guesstimate they compare known populations living that style of existence and extrapolate a logical and reasonable if not absolutely perfect population figure. The point is that we are currently in an ongoing population explosion which is unlikely to carry on for 100 years. Doomsday repeats itself until a stable population is agreed upon and enforced.

Either population levels off and stabilizes or it collapses. My guess is that if you could graph this out for another 10,000 years the population would drop back to 100 million (0.1 billion), the population of the 500 AD period. Then one of two possibilities. Either there would be an enforced world-wide population policy maintaining a stable population with a very good standard of living for everyone. Or alternatively there would be no population policy and the population would go through boom and bust cycles with lots of conflict and many wars. There would be massive squalor for most of the people most of the time. To attain the healthier outcome there would not have to be regulation of anything except population and communities of people could live as they choose. With a smallish human population existing well within nature’s ability to furnish us with necessities, everyone could live the very long and happy life they chose for themselves. I love my sexual freedoms but a two-child family seems just fine. I knew the founders of the Sexual Freedom League and was paid real money for designing their logo back in 1967. There are some movies of me romping in Aquatic Park Beach with Jeff and Ina before the newspapers picked up on Jeff and his quest. I am not exactly your typical old dude prude.

(( I just had a computer crash. COMMENT about my website provider WORDPRESS’s word processor) I just spent two hours creating a beautiful html chart showing in considerable detail a much better proof for the above speculative assertions. Before updating I did a ctrl-a, ctrl-c and then hit update. I do this temporary backup because several times in the past all my work was lost when I clicked the “post” button. Perhaps this time I hit ctrl-a, ctrl-v and that inadvertently replaced all my work with blank because nothing was in temporary memory. In any case everything that was part of my new stuff was lost. This is a serious flaw with Windows and with word processors! It could be easily fixed by having the temporary ctrl-c have several layers deep of backup. I will now redo that chart but in a safer way by posting the blank chart to the internet and then filling it in. Thus for a while there will be a work chart in progress. Possibly my problem was created by my moving my cursor-mouse-pointer off of the UPDATE button between clicking it and releasing it. I don’t know what actually happened.))

Before Present World Population % growth 100 yr Doubling time 100,000 10,000 – – 30,000 500,000 0.56 12,403 10,000 6,000,000 1.25 5,580 5,000 50,000,000 4.33 1,635 3,000 120,000,000 4.47 1,583 2,000 250,000,000 7.62 944 1,000 250,000,000 0.00 – 800 400,000,000 26.49 295 600 375,000,000 -3.18 slight shrinkage 400 578,000,000 24.15 320 300 680,000,000 17.65 427 200 954,000,000 40.29 205 100 1,634,000,000 71.28 129 50 2,530,000,000 139.74 79 0 6,000,000,000 462,42 40

This is chart is copied by hand from Maps of Time, page 143, by David Christian. This chart is much more carefully compiled than my quick estimates done above, and it shows even more clearly the idea that until very recently no one would notice a population growth. When the first pyramids of Egypt were built 5000 years ago, the % growth was 4.33 per 100 years and so with a life expectancy of 25 years a person living in a town of 100 people would have seen 101 people at their death. With infant mortality being high a single extra person in a small town would be invisible even to a modern statistician. Whereas at present, with a life expectancy of 80 years for women and a doubling time of 40 years, the community of 100 people would have doubled twice and be about 400 people. People living to old age will have seen extraordinary growth! It has been tolerated in the modern world because there was an abundance of everything for everyone. Such growth is what’s happening now, and not to a just a single small village, but to our entire Earth. Our current pattern of population growth is a temporary phenomenon.

Things are much better now than they have ever been.