Ten doublings

I heard another ‘expert’ on the radio today
wittering on about the aging population of the UK;
bemoaning the fact that our fertility is in decline
and claiming that we needed ‘growth’ to prosper.
That educated people are so oblivious of reality
Is, I think, far more than just a pity.
Examining the facts:
Yes, we’re having less children.
But there are more new mouths, not fewer.
And because we’re living longer,
population’s increasing faster still.
Assume just a ‘tiny’ 1% growth in people.
Our population will double in just one lifetime.
(Don’t believe me? Watch this.)
In ten lifetimes, that’s ten doublings.
Ten doublings: one thousand people
standing where there is just one today.
By the year 2750
unless we come to our senses,
we’ll all be standing shoulder-to-shoulder.
Fun, eh?
By the way,
this ‘expert’ also said
that he ‘didn’t hold with global warming.’
His great-great-great-grandchildren
(in their multitudes, if he has his way)
will claim he was a fool, or insane.
Assuming they survive the wars.

About pendantry

Phlyarologist (part-time) and pendant. Campaigner for action against anthropogenic global warming (AGW) and injustice in all its forms. Humanist, atheist, notoftenpist. Wannabe poet, writer and astronaut.
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10 Responses to Ten doublings

  1. Wendy says:

    Do you want to hear another expert on the radio? http://www.bbc.co.uk/iplayer/episode/p00230y4/Ronys_Forum_05_02_2009/ If you want to listen you\’ll have to in the next two or three days cos it will disappear… listen for my dulcet tones after the first ten minutes of the show! :P


  2. Pingback: “Arithmetic, population and energy” by Dr Albert A Bartlett | Wibble

  3. pendantry on behalf of Martin Lack says:

    Martin – I’ve taken the liberty of posting your recent comment on this thread (where it belongs).

    Colin, 12 months ago, the UN predicted that it was most likely that population would stabilise by 2100 at around 10 billion. However, if we fail to get control of fertility in poor countries (due to failing to educate and emancipate women), population will continue to grow in a linear fashion (i.e. not a survivable option). Alternatively, if people in developing countries finally begin to see the benefit in controlling their procreation (as a means to escape the poverty trap) then total global population might actually peak at less than 10 billion.


    Therefore, the future of global population lies in the hands of poor people currently having too many children (who are not dying as a result of our intervention). That is to say they have got stuck with high birth but low death rates; and need to complete the demographic transition from high birth and death rates to low birth and death rates.

    I agree with you that all of this is scary. Exponential growth is scary. Doubling time is approximately = 70 divided by annual percentage growth rate. Therefore, doubling times are as follows:
    1% growth = 70 years
    2% growth = 35 years
    5% growth = 14 years
    10% growth = 7 years.

    I therefore don’t get your “ten doublings” post at all because if world population were to grow at 1% per annum it would double to 14 billion by 2070, 28 billion by 2140, and 56 billion by 2210. However, as Jared Diamond and James Hansen have pointed out, none of that is going to happen because the ecological carrying capacity of an Ice-free Earth (w.r.t. humans) will be only a fraction of it current value (which we ave already exceeded). Therefore, we either choose to bring the human population on this planet under control; or ecological reality will do it for us.


    • pendantry says:


      I don’t understand what you don’t understand about the ten doublings: 2 raised to the power 10 (ie, ten doublings) is 1024. The doubling rate at 1% is the proverbial ‘three score years and ten’. Ten times 70 is 700 years. Seven hundred years from now takes us to (roughly) AD2750. Assuming a continuation of this ‘tiny’ growth rate (1%) — and ignoring the practicalities of feeding/ clothing/ housing/ educating etc — there would be roughly seven thousand billion humans.

      …if world population were to grow at 1% per annum it would double to 14 billion by 2070, 28 billion by 2140, and 56 billion by 2210

      That is exactly my point. The global rate of population growth of homo fatuus brutus is currently approximately 1.3%pa (note: 1.3% > 1%). The UN’s numbers don’t explain how we’re — suddenly, magically — going to switch from a situation where instead of doubling our numbers every seventy years, everything will be stable at approximately 10 billion (give or take a billion, or two) by the end of this century.

      If population growth is to subside, something drastic is going to have to happen. Wars, diseases, mass famines, yes, clearly these are drastic (and only a madman actually wants them).

      If there is to be a peaceful, managed transition to the UN’s numbers — one that doesn’t involve megadeaths — the drastic changes will have to be in our minds; in the way in which we perceive the act of procreation. So:

      • Will society provide financial support for parents, or will there instead be financial incentives to remain childless? How will in-vitro fertilisation (IVF) be viewed?
      • Will we continue in the view that everyone has a ‘right’ to have their own children, or will it only be the richest of the rich who get to spread their seed?
      • Will we continue to pursue extension-of-life to the (IMO crazy) extent we do now — or will ‘early retirement’ take on a new meaning?
      • Will we still celebrate births (and birthdays)? Will we toast great-great-(great-great-?)grandmothers — or will they be stoned as pariahs?

      Bland reassurances, such as are implicit in the UN’s numbers, that all will be (more-or-less) well don’t even hint at such issues.

      And when I rail at those who blame the third world’s profligate and irresponsible growth, what I mean to refer to is a phrase with which I feel sure you’re familiar: ‘before attempting to remove a splinter from the eye of another, first remove the plank from your own’. We’re all in this together; pointing fingers elsewhere is a symptom of denial.

      Make Room! Make Room! Anyone for Soylent Green?

      As always: I’m happy to be proven wrong :)


      • Martin Lack says:

        We are both right. By the time I crawled in to bed last night I realised I had misunderstood your comments about ten doublings (i.e. 2x2x2x2x2x2x2x2x2x2). If you had said the population will be 1024 times greater (rather than 1000 times greater) I would not have been confused. However, this is such an important issue, I think I will re-visit on my blog. Thanks for the inspiration. (I still think the locus of the problem lies outside the developed world).


        • pendantry says:

          It’s entirely possible you’re not wrong; I certainly don’t claim to know it all. I keep looking for the growth rate of homo fatuus brutus’ ‘first world’ (AKA ‘Western’ AKA ‘civilised’) chapter, and haven’t yet found it. I appreciate it will be less than 1% (but I’d be willing to wager it’s not negative; I only have to look at the way the other branches of my parents’ offspring continue to grow to see that) — it will be interesting to crunch that number the way Professor Albert Bartlett taught me to


          • Martin Lack says:

            The UN website includes the facility to look at projections for any individual country if you want to; and the early part of the graph will indicate the current trend…?


          • pendantry says:

            Ah, I see, you refer to the World Population Prospects, the 2010 Revision? Lots of numbers there, would take some time to crunch.

            Thinking parochially for a moment (a thing I do try to avoid in a topic that has a global scope) allows me a riposte to the ‘but it’s not us, it’s them‘ stance: the UK’s ‘average rate of population change’ (which will, I suspect, be confused by the inclusion of immigration/ emigration) is 0.6%. This means that we in the UK have a doubling period of 70/0.6= 117 years, which is a smidgeon less than half as fast as the global 70/1.3= 53.8 years* — but even so, it’s increasing, not stabilising; and as Professor Bartlett warns: in an exponential growth situation it’s actually much closer to midnight than knee-jerk ‘common-sense’ would have one believe.

            Yes, I know, it’s complicated by immigration/ emigration (I believe I already said that): I dunno about you, tovarishch, but as far as I’m concerned we’re all human, and we’re all in this together, despite the perpetual nationalism prejudices that are the legacies of a bygone era that some would, in denial of reality, prefer that we continue.

            * I cannot now recall where I got the global 1.3% increase rate from. I can find nowhere on the World Population Prospects where they aggregate the numbers. It’s almost as though nobody wants us to look at the big picture…


        • Martin Lack says:

          Deflecting attention somewhere else is what Clive Hamilton calls a “maladaptive coping strategy”; one that climate change sceptics use all the time (e.g. claiming any Western mitigating actions will be wiped out by construction of coal-fired power stations in China)…

          I therefore suspect that you feel this is exactly what I am doing (maybe I am). I certainly agree that we must all take responsibility for our own fertility and – as I am sure you appreciate – I am not in denial about the ultimately problematic nature of growth; be it in population or resource consumption of any kind…

          However, despite all that, I really do think that our biggest problem lies within the minds of the world’s poorest people in countries where population growth is yet to decline to Western levels and – to be quite frank with you – this is the view of the UN (and they are not in denial about the reality of growth as our ultimate problem either).


          • pendantry says:

            I’ve just reviewed this thread and feel the need to riposte that our biggest problem lies within the minds of all those who find it easy to dismiss the real world practical needs of others on the grounds that ‘they’re not like us’. We’re all in it together.


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