So Much for the Overpopulation Scares?.......

Discussion in 'Biology & Genetics' started by exchemist, Nov 9, 2018.

  1. Write4U Valued Senior Member

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    18,577
    My point was that fertility rates or birth rates have nothing to do with population growth, except for a longer or shorter time frames (doubling time). These rates ignore death rates. You need both in order to establish population growth or decline.

    If death rates exceed birth rates the population will decline . If birth rates exceed death rates the population will grow, until it reaches unsustainable numbers. Then birth rates and fertility rates will reach a forced zero or we have a nice big war or a pandemic.

    I appreciate your attention to detail. But in your zeal to correct me you miss the IMPORTANT point about the exponential function, which was the subject of my post.

    In the long run, birth rates and death rates will reach zero, and it will do so by our choice or by nature's choice. That is the dilemma at hand!
     
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  3. Beer w/Straw Transcendental Ignorance! Valued Senior Member

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    Is that an apocalyptic movie plot?
     
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  5. billvon Valued Senior Member

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    Birth rates have nothing to do with population growth? You are either nuts or are too egotistic to admit you were wrong.
    No, they won't.
     
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  7. Write4U Valued Senior Member

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    18,577
    Perhaps I could have been clearer. Birth rates alone do not produce a population growth rate. It has to be off-set by death rates to know the population growth rate, at which time the exponential function will predict the future population number.
    OK, the long term difference between birth and death rates determine percent population growth and the applicable exponential function.
     
    Last edited: Nov 14, 2018
  8. Write4U Valued Senior Member

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    18,577
    1% steady growth in population results in a doubling time of 70 years.
    2% steady growth in population results in a doubling time of 35 years.

    The current world population growth rate is about 1.2 % which translates in a doubling time of 70/1.2 = 58.33 years! This is basically my posit on the OP question about overpopulation.

    If you have watched Prof Albert Bartlett (prof. emer. in mathematics), you will see that when there is steady growth in limited spaces or with limited resources, statistically zero growth is a mathematical inevitability.

    And this zero growth is either a voluntary act of choice by humans or nature will decide for us. We can lower the birth rate or increase the death rate or nature can unleash a natural disaster, or a pandemic, or starvation and kill a few billion in one fell swoop.
    Is that not already becoming obvious?

    Fortunately, the population growth is already slowing down, increasing the doubling time, but we are talking about a time frame of a single generation (lifetime).
    IMO, it is indeed a human dilemma...

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    Last edited: Nov 14, 2018
  9. Jeeves Valued Senior Member

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    So...?
    Will the anthropocene epoch end in a series of bangs or a huge chorus of whimpers?
    The human race has already reduced all other species by 60% - in as short a time as a meteor strike could have.
    If the resource and land-use wars don't reduce the human population sufficiently, climate change will have to.
     
  10. Write4U Valued Senior Member

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    18,577
    It will, unless we curb our use of natural resources. The exponential function applies to anything with a steady growth factor.
    We will probably see the end of oil in about 40 years and when we replace oil with coal, it will run out in about 100 year . From Worldometers;
    http://www.worldometers.info/

    Note; all figures are at current rates and for current population needs. These rates will increase along with population increases and energy demands.
     
    Last edited: Nov 14, 2018
  11. Write4U Valued Senior Member

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    18,577
    No, that is the conclusion by professor emeritus in mathematics, Dr. Albert Bartlett.
    Actually, he explains how an apocalyptic scenario could easily unfold before our eyes.
    His point is that either we control population growth for sustainability or nature will choose for us and it will be apocalyptic. Therein lies our dilemma.

    See post #7. If you take the time to watch even part of his lecture on the Exponential Function, especially as it pertains to population growth and its longterm consequences it will remind even the educated viewer of this real time mathematical function where a continued population growth factor of just 1%, will result in a "doubling" every 70 years (69.3). This is nice if you have 7 million dollars in the bank but if it is 7 billion people, 70 years will result in 14 billion people demanding food, clean water, and energy sources for transportation and industry. And if this measly 1 % growth were to continue, it would result in 28 billion people in 140 years, 56 billion in 210 years, just three generations.

    Clearly, population growth will come to a halt at some point in time.

    His opening line is; "The greatest shortcoming of the human race is our inability to understand the Exponential Function" and he makes a persuasive argument illustrating this problem.
     
    Last edited: Nov 15, 2018
  12. Write4U Valued Senior Member

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    18,577
    If you watch the Bartlett lecture, you will see that the most likely scenario is a natural calamity, because we are not inclined to advocate for increasing the death rate to offset any growth in birth rate.

    Unless we decide on a nuclear war that kills a few billion souls. That'll help with the problem of continued population growth.
     
  13. exchemist Valued Senior Member

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    11,194
    I see more eyeball-rolling hyperventilation on this thread about the exponential "function".

    The whole point of the article I posted in the OP is that fertility rate drops as societies get wealthier, which they are doing rapidly. This in turn reduces the rate of growth of the population, to the extent that the population is already falling in a number of countries and others can be expected to follow. While, as others have pointed out there is no room for complacency over human use of resources, it does show there are already powerful corrective factors at work that help ameliorate the problem.

    So the mathematics prof needs to factor into his model that the exponent in his exponential "function" is itself a variable and is getting smaller. Any extrapolation based on a fixed growth rate will be wildly wrong, exactly due to the amplifying nature of the exponential "function".

    [That's enough "functions". Ed.]

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  14. Write4U Valued Senior Member

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    The same holds true for using "current" growth figures in any extrapolation as long as there is any growth at all.

    The point is that eventually zero growth must happen in a limited space or with limited resources.
    This is what the chart predicts by 2100. The growth rate may slow to .1 %, yet the population will have grown to 11.2 billion (and still growing).
     
    Last edited: Nov 15, 2018
  15. Jeeves Valued Senior Member

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    And temporarily. There is a limit to wealth, which is being approached even more rapidly, as mechanization meets, then exceeds, employment - in about ten years. https://www.forbes.com/sites/quora/...0-of-the-jobs-humans-used-to-do/#d98b9dd1bdd8
    The much bigger problem is rapid loss of habitable land, https://ourworldindata.org/land-cover
    the catastrophic loss of pollinating insects https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/pollinator-decline
    and the volatility of weather systems, notably the dispersion of water.
    Simply, this means, more and more people have to live in a smaller and smaller area with less and less to eat.
    As these changes are taking place much faster than natural birth-rate reduction, and since humans are (potentially) long-lived and (generally) have a strong survival instinct, conflict on a very large scale is inevitable. https://owlcation.com/humanities/Climate-Wars-A-Review
    Where?
     
  16. billvon Valued Senior Member

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    20,602
    I've heard this before.

    "The battle to feed all of humanity is over. In the 1970s hundreds of millions of people will starve to death in spite of any crash programs embarked upon now. At this late date nothing can prevent a substantial increase in the world death rate."

    Fortunately, that didn't happen. Technology has a way of changing to support more people. There's a limit to that, of course. But whenever I hear that within "about ten years" there will be an artificial limit that we can't get around - we always seem to find a way around it.
     
  17. iceaura Valued Senior Member

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    30,994
    What did happen - as might have been predicted by someone with a background in anthropology or sociology rather than entomology - was war, disease, political collapse, genocide, etc (along with the "green revolution").

    These happened in the exact places on the planet where the naive predicted humans would first sleepwalk into starvation.

    As far as technology changing to support more people - when those people get a look at what their lives are going to be like with a new "technology" that can handle 11 billion people during massive climate changes, there will probably be trouble. Just saying.
     
  18. billvon Valued Senior Member

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    Yep. As it has since the beginning of history.

    What didn't happen was the "hundreds of millions of people" starving to death. Population growth continued without a hitch.
     
  19. iceaura Valued Senior Member

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    30,994
    Focused on the exact places where population overshoot was occurring.

    Which nowdays would be a fair proportion of the planet.
    Not quite. There were hitches - in Rwanda, in the USSR, etc.
    A comparable set of hitches tomorrow would include Mexico, Pakistan/India, some regions in SE Asia and Africa, etc - a larger area, and more difficult to "contain".
     
  20. Jeeves Valued Senior Member

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    5,028
    It did, it does, and it's not going to stop. The numbers may have been lower than some predictions, but that's no big help to the refugees in barbed wire enclosures or caravans met by five heavily armed soldiers for each man, woman and child. The situation didn't change. Conflict and hunger continue unabated, unsolved, just as it has all through history, only each cycle includes more regions, disparate regions - it just keeps spreading.
    https://www.oxfam.org/en/emergencies/famine-and-hunger-crisis
    https://scroll.in/article/854073/wo...rea-these-charts-show-how-hunger-haunts-india
    https://www.one.org/us/policy/ethiopian-famine-25th-anniversary-questions-and-answers
    https://www.cnn.com/2018/11/09/middleeast/yemens-plight-lister-analysis-intl/index.html
    It won't all happen in ten years - it will drag on and on, but it will keep accelerating, until it ends. Some way.
     
  21. billvon Valued Senior Member

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    20,602
    It is decelerating.
     

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  22. Jeeves Valued Senior Member

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    5,028
    We'll see.
     
  23. iceaura Valued Senior Member

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    30,994
    Too late.

    We've been avoided famine by eating crude oil, essentially. (That and some timely plant breeding). That allowed further overshoot.
     

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