Humanity to 2100: a new demographic analysis

Today I started to write a post about last night’s American presidential debate.  I live-tweeted the whole thing, listening and typing frantically in my office with only cats for company. It felt like having rocks tossed at my head.   Revisiting my notes this morning felt like discovering the text of a lost Phil Dick novel, surreal and disturbing.

So instead I will blog about something at a complete different scale.  Something that doesn’t feel like having rocks hurled at my face when I write about it: demographics.

Demographics, yes, that essential tool in the futurist’s toolkit.  A way of looking ahead at a large scale, working with large amounts of data to identify powerful trends. Readers know that I’ve been looking into demographics for a while.

A recent paper in the Lancet offers some simulations of human population growth through the year 2100.  Vollset et al conclude that fertility rate (the number of children per woman) will keep dropping and what we’ll pass peak population two-thirds of the way through our century.  This is vital reading for anyone interested in the future and for anyone looking ahead for higher education.

Key takeaway:

[B]ecause of progress in female educational attainment and access to contraception contributing to declining fertility rates, continued global population growth through the century is no longer the most likely trajectory for the world’s population.

Total humanity: “the global population was projected to peak in 2064 at 9.73 billion (8.84–10.9 [billion]) people and decline to 8.79 billion (6.83–11.8) in 2100.”  Put another way, “continued global population growth through the century is no longer the most likely trajectory for the world’s population.”

The age of the typical (well, median) human keeps rising: “Mean age was forecasted to increase in the reference scenario from 32.6 years in 2017 to 46.2 years (43.4–47.8) in 2100.”  Further,

The number of children younger than 5 years was forecasted to decline from 681 million in 2017 to 401 million (251–704) in 2100, a drop of 41·0% (23.5–51.8). At the same time, the number of individuals older than 80 years was forecasted to increase from 141 million in 2017 to 866 million (617–1140) in 2100.

Fertility rate: “The global TFR in the reference scenario was forecasted to be 1.66 (95% UI 1.33–2.08) in 2100.”  Which is a big change from the recent past:

fertility rate 1990-2100 Vortel et al

Life expectancy keeps rising, but there are variations: “life expectancy was forecasted to increase, the rate of progress is likely to slow.”

Large inequalities remained at the global level in 2100, with forecasts of country and territory life expectancies for both sexes combined ranging from 69.4 years (95% UI 61.4–76.0) to 88.9 years (85.0–92.6)… The standard deviation of life expectancy across countries and territories narrowed from 6.9 years in 2017 to 3.6 years in 2100… Ten countries were forecasted to still have life expectancies lower than 75 years in 2100, seven of them in sub-Saharan Africa.

Gender differences look strong, as per usual;

life expectancy 2000-2100 Volset et al

Why does all of this matter?

After all, some of us have been discussing this sort of thing for a while. Birthdates declining?  Check.  Rising median age?  Check.  Central Africa the main source of childbirth?  Got it.  A shrinking total population?  Indeed.

There are reasons.  First, it’s a lower estimate than what we’ve seen elsewhere.  The authors cite two leading sources envisioning fertility rates a bit high, around 1.75.  It’s also lower than what the United Nations thinks, which is quite the authority.  (A Future Trends Forum guest speculated that the relevant UN agency was inflating figures.)

Second, for folks who haven’t been paying attention to the massive sea change in human demographics, this might be some of the best modeling we have.

I’ve written about what this means for society and education elsewhere: good news for the natural environment, a triumph for health care and public health, challenges to economies. The primary and secondary school pipeline narrows, followed by the traditional age undergraduate population.  We have to take lifelong learning seriously.

That’s it for now.  I’m still resisting writing about the debate.

(thanks to my splendid wife for the links)

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4 Responses to Humanity to 2100: a new demographic analysis

  1. Ruben Nelson says:

    Given the complex living mess of messes we are in, it is virtually certain that there will be far fewer of us in 2100 than offered by the folks in the Lancet article.
    This is not to judge them. Theirs is a surprise free analysis. As such I have no quarrel with it.
    But given even present conditions, let alone how they will morph and intensify over time, there will be surprises. Most, but no all, will tend to reduce our population.
    There will be grief and despair.
    As Thomas Homer-Dixon says in his new book, “Commanding Hope”, “As the century unfolds, fear is likely to become humanity’s overriding emotion.”

    • Bryan Alexander says:

      Ruben, thank you for the very dark comment.

      Which population-reducing surprises do you envision?

      I don’t know Homer-Dixon, but am intrigued. That line reminds me of Bruce Sterling’s quote about the 21st century: “old people in big cities, afraid of the sky.”

  2. Shannon Connelly says:

    Bryan, this comment is not about demographics, rather it’s a topic idea for a future message. (I wasn’t sure of the most efficient way to deliver this information to you.) An area of focus for many institutions in the coming year will be around working from home post-pandemic, especially for those in a non-essential and/or non-student-facing role. I would love to learn more about how other schools are considering this option (or not considering it), and how it could potentially be implemented in an industry that historically has not embraced this arrangement. Thanks much for considering this topic!

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