Predictions of Environmental Doom

Discussion in 'Earth Science' started by madanthonywayne, Apr 21, 2011.

  1. Trippy ALEA IACTA EST Staff Member

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    Additionally, to address what you've had to say about immigrants...

    I think that immigrants, for the most part, assimilate.
    I think that within one or two generations, the family size of a migrant family approaches that of the host nation.
    I think this is well illustrated by Pakistani immigrants to the UK.
    As near as I can figure, on average Pakistani immigrants to the UK have around 2.7 children per family, however, for example, I also know that there are as many pakistani immigrant families in the UK that have 1 child, as there are that have three - a very flat distribution which is probably diagnostic of precisely the kind of transition I'm talking about (the average familiy size of white folk in the UK is more like 1.8).
    Compare this to the average size of families in Pakistan which is more like 3.2

    I'm also given to understand that naturalized immigrants in Germany are considered "Germans of immigrant descent" until the third generation, however, Germans of immigrant descent are still Germans, which suggests that the 'Live Births' line on the graph I posted earlier includes births to those people who have immigrated to Germany and become naturalized citizens of Germany, which tends to be supported by the positive excursion in live births between 1987 and 1993, which coincides with a larger period of growth in the German population, an increase, and subsequent plateu in the number of foreigners in Germany, and the current events and politics of this time which meant that:
    1. There was an incentive to move to Germany (East or West) and/or
    2. It was easier to migrate to Germany.

    All of which seems to suggest that your objections are unfounded.
     
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  3. iceaura Valued Senior Member

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    No, I'm not. I'm observing that your presumptions about "continuing trends" (which ones to attend, how to project them, which ones to ignore, etc) are critical to your projections from the current data. And the more explicit you become about the ones you find important, and the ones you choose to ignore, the less plausible a rosy scenario of conveniently plateauing wealthy populations becomes.
    Whatever "natural change" means. I find immigration to wealth and replacement of low local fertility a perfectly natural phenomenon.

    The population is not declining. It has not definitely plateaued, if the overall shape of the curve is taken into account rather than a couple of year to year numbers. It is increasing, as far as we can tell. Agreed?

    Three large categories of functions (polynomial with fractional exponent, logarithmic, hyperbolic) including major features of most population growth models.
    Which addresses neither category, without assumptions about that variability and the current situation - that would require data support, and mechanism, and a specific model. Otherwise, my term "indefinitely" fits the data we have ( increase nowhere near being obscured by inter-annual variability, barring possibly Japan if nothing changes there for two generations).
    The first one is wrong in describing that as the current trend (the second derivative is not becoming increasingly negative at a constant rate). In the first two, the population never plateaus - it passes through a zero growth moment (a value which in an actually discontinuous situation, such as we have, it may never actually take on or "reach"), and declines from there with acceleration - a crash. In the third, the "inflexion" requirement is an error, and the conclusion is false - growth functions with a continuously negative second derivative approaching zero in absolute value can approach an asymptotic line of arbitrary slope, and yield a rapidly increasing (linearly, but at a high rate) population forever.
    And I agreed - a necessary, but not sufficient, condition. You found fault with that, for some reason.
    No, it doesn't. It directly counters his one claim, which is that a population growth curve with a continuously negative second derivative must eventually plateau. The claim is false. It is also false in your significantly amended form, in which inter-annual variability is to swamp the growth signal at sufficiently large population levels - the asymptote can be of arbitrary slope.

    And the amended form requires quite unrealistic assumptions, for the OP topic.
    Which brings us to this:
    1) It wasn't a model. 2) This entire subset discussion was launched by my objecting to naive, unrealistic, and mathematically invalid projections of supposed properties of current population growth curves as if they were based in the certain properties of mathematically sure modelings of actual population growth.

    The other side of my original remarks - that the entire discussion of plateaus etc is meaningless without some idea of the disaster levels we face, and the physical reality will trump the modeling features - you haven't deigned to notice. The OP topic is predictions of environmental doom. Let's start here: have we already passed the doom level of population size? We do seem to be running into the kinds of troubles a crossover of a tipping point would feature: the loss of the major fisheries, the loss of large bodies and regions of formerly productive water, various synergistic effects of waste and degradation products (global warming, etc), public assertions of capability in response that rest on physical improbabilities and the emergence of saving factors as yet unseen, etc.

    To return to those three little examples above, in our new mode of invoking realilty: If the global population continues to increase until a major disaster hits - say: a plague in China, spreading to India, that kills five million people in a couple of months and by destroying the majority of the social infrastructure for the planet (revealing the overshoot weaknesses) throws the population curve into a crash from there - then the transition from increase to decrease would never include ZPG. The derivative of the correct growth function would be seen to have been discontinuous, if you want techie speak.
     
    Last edited: May 19, 2011
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  5. adoucette Caca Occurs Valued Senior Member

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    No.

    The population is indeed delclining and for more than for a couple of years.

    The peak was 7 years ago in 2003, but even then the population has essentially been unchanged since the early 90s (varying just a tiny fraction of a percent year to year)

    http://www.google.com/publicdata?ds...lse&rdim=country&idim=country:DEU&hl=en&dl=en

    Will this continue?

    http://www.destatis.de/jetspeed/por...ation/GermanyPopulation2050,property=file.pdf

    Arthur
     
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  7. Trippy ALEA IACTA EST Staff Member

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    Yes, you are ignoring the factors that seem to have driven the growth in the first place. If you were considering them, you would have realized that beginning with the collapse of the Soviet union in 1990, through until the tightening of requirements for political asylumn in 1993, the pressures causing the large amount of immigration seen starting in 1987-1989 relaxed substantialy - a hypothesis that so far seems to be supported by the available evidence.

    I've addressed all the trends displayed in the available data, so it's a moot point.

    Natural change is a well defined term in demographics, it's not something that I have just made up. Which, you might have been able to infer, if you had explored the link provided to you by Adoucette.

    No, I disagree, I believe, based on the evidence in front of me that if the natural change maintains its current range, and the immigration maintains its current range, then the population will stay at approximately the level it is now, barring things like the German government trying to encourage immigrants (which would increase the foreign population and force growth), or some event that results in an increase in the number of refugees to Germany, or the German Government incentivising child birth (which research suggests probably won't work anyway) or perhaps a massive grass roots movement gripping the country pushing people out of the cities and back into the country (rural populations tend to have higher fertility rates then urban populations).

    Stop being so lazy and prove it - if you don't have excel, there are plenty of other tools you can use.
    As to this statement: "increase nowhere near being obscured by inter-annual" this is a strawman hypothesis, I never claimed that it was true in all cases, only in cases where indefinite growth occurs at a rate aymptoticaly approaching zero.

    Wrong - I've provided you with the graph of the world population, and I stated at the time that you could fit it with a linear least squares with an R[sup]2[/sup] of 0.85 which is a far better fit than, say, most climate change data.

    I quantified the claim WRT 'plateuing', this changes nothing.

    There seems to be some confusion in your post.
    At the moment, the trend in the global population is for the second derivative to be negative, and to follow a trend with a negative slope. The trend with the negative slope (in the second derivative) extends back to 1970 or so. In order for the second derivative to remain negative, but increase amysptoticaly towards zero - which is the scenario you described, it must first pass through an inflexion - a sign change.

    This is a strawman hypothesis - the second time it's been presented in this post. I never claimed that it was true that in all cases interannual variability would swamp a growth signal, I only claimed that it was true in scenarios where the growth asymptoticaly approached zero.

    Strawman hypothesis, I didn't claim that it was a model, only that there were features in the data set that it failed to model (or account for).

    The hypothesis forwarded by Fraggle Rocker, and supported by myself, and by Adoucette, is one that is supported by all of the available evidence, a portion of which has been presented in this discussion. You've been presented with facts, figures, statistics, graphs, and even causal mechanisms, however you've rejected it all out of hand, much of it without seeming to have given it any consideration, and favoured instead speculation which you have been utterly unable to substantiate.

    Actually, I have specifically deigned to notice, and even addressed some of the aspects of the physical reality, even tried to draw your attention to them, seemingly to no avail.

    Asked an answered in this thread.

    You're wrong here as well, whilst it might be true of one, specific scale, it won't be true of all scales. It would take something like... The Rapture, divine intervention, or maybe the detonation of a nuclear weapon in a major metropolitan center to produce that kind of change. A change of 5 million people over two months is still smooth and differentiable across its entire length.

    Do you want to invoke divine intervention to support your argument?
     
  8. iceaura Valued Senior Member

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    24,272
    The population rose last year, and the year before. Not much, but:

    The bump in the graph looks much like the earlier one, which proved to be a way station in an overall rise.
    If that's the meaning you are using, it's irrelevant.
    Well if nothing changes then nothing changes, I'll give you that.
    Prove what? That functions exist that rapidly increase without bound forever despite continuously negative second derivatives? You've got to be kidding. That the three kinds I mentioned are important constituents of most population growth models? That's blue sky observation.
    Uh, yes? Your point?
    That's nonsense, as written - are you talking about the third derivative changing sign? (and claiming it to be a constant in fact and future, meanwhile? mechanism necessary, for that one).

    In the second place, the original discussion was not confined to whatever function you have decided to fit to the actual population growth curve - we were discussing a mathematically forced property of all possible growth functions with negative second derivatives. It isn't there.
    You were invoking it in response to examples of population functions that do not asymptotically approach zero rates of growth - that was the whole point of them.
    Your "evidence" is unsupported extrapolation from dubious assumptions about "current trends" no better supported by the evidence than the doomsayers' prophecies.
    Not answered, here or to my knowledge anywhere.
    What we have for "answers" is shit like this:
    Tip: Omniscience is not your forte. At least consider the more obvious signs of trouble - including, while you are at it, the very much non-zero possibility of a nuclear weapon detonating in a major metro area. I would think a plague of the right kind would have far more effect than that, but perhaps perhaps an overshoot (if we are in one) would be revealed by even such a small and localized event, with repercussions.
     
  9. adoucette Caca Occurs Valued Senior Member

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    No Ice it didn't.


    It's dropped EVERY year since 2002 or 2003 depending on whose figures you use, but none show it growing.

    http://www.destatis.de/jetspeed/por...ontent75/lrbev03a,templateId=renderPrint.psml

    http://www.indexmundi.com/germany/population.html

    To claim it has not plateaued for nearly two decades is simply FALSE.

    Sure it could rise again, but as I pointed out, the Germans themselves are expecting it to continue to decline.

    http://www.destatis.de/jetspeed/por...ation/GermanyPopulation2050,property=file.pdf

    Arthur
     
  10. Trippy ALEA IACTA EST Staff Member

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    The rate at which births exceed deaths in a naturalized population is irrelevant to a discussion of the growth of that population?

    Are you sure? Because that sure doesn't sound right to me.

    I think it's up to you at this point to prove that it's irrelevant.

    Prove they're relevant.
    Prove they fit all of the aspects of the data - including the apparent levelling off of the first derivative.
    Prove they're capable of accomadating a sign change in the first and second derivatives.

    Otherwise, they're useless.

    My point is that my assumption fits the measured data. My hypothesis (for lack of a better word) matches obervation, therefore it is not "wrong in describing that as the current trend".

    No it isn't, I used the wrong word, I'm surprised you didn't pick it up. I have (mistakenly) been using the term 'Inflexion point' where what I have been describing is a stationary point. I was also discussing two seperate scenarios, those two sentences should have been seperated into different paragraphs.

    Asked and answered.

    I was discussing a specific case, the case fraggle mentioned, and a case you discussed, and a case that I have explicitly stated I was discussing repeatedly - that where the population grows indefinitely, but asymptotically approaches some fixed value.

    No, I have been quite clear, and quite explicit that that reference was regarding situations where the growth rate aymptotically approaches zero.

    Scare quotes are un-neccessary - your sentence structure clearly demonstrates non acceptance of terminology, and neutral distancing - unless you're trying to use them in an attempt to ridicule.

    The simple fact of the matter is that the scenario posed by Fraggle Rocker has mutliple, independent lines of evidence that support it - ranging from the demographics of almost any European Country you might choose, to the changes in behaviour of immigrants from poorer countries to more propserous countries, to the contrasts in the demographics of Pakistan. A clear correlation can also be shown accross multiple countries. Several causal mechanisms have been proposed, some, or all of which have been mentioned in this thread, or linked to in this thread.

    The point being, that on my side I have emperical evidence, and causal mechanisms. You have speculation.

    Well, it has, in fact, been discussed.

    Tsk tsk, it's comments like this that cause flame wars to start.

    It's a valid point, if you consider what it means for something to be 'smooth and differentiable' or 'continuous'. It requires some kind of discontinuity (eg, the behaviour of y=1/x at x=0). It requires a vertical slope or something similar to that shown by y=|x|. To acheive this would require the sudden, instant, and simultaneous removal of members of the population - something that can only be achieved through things like divine intervention or the use of nuclear weapons, anything less will result in a line that has a large, but still finite slope.

    I'm not claiming to be omiscient, nor is omniscience implied by anything I have said.

    I have, hence some of the other comments I have made in this thread, however those points may have been too subtle for you.

    Obviously I've considered it - it was me that bought it up, after all. How can I bring somethign up if I haven't considered it?

    It might cause more deaths, but the problem you face is one of time and timing. In order to produce a curve that isn't smooth and differentiable, you need to be able to generate a vertical slope. Not a slope that is vertical at some scales, not a slope that is to all intents and purposes vertical, but a slope that is genuinely vertical at all scales. This requires the death of large numbers of people simultaneously, because anything less, at some scale on the time access will produce a line that has a large, but still finite slope.

    And no, I don't consider the death of one person to cause an discontinuity, because we're describing a discretized variable.

    Come to think of it, a Nuclear bomb probably isn't that great an example, because the death causing agents travel outwards at a finite speed.
     
    Last edited: May 19, 2011
  11. Trippy ALEA IACTA EST Staff Member

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    Actually, you know what?

    Don't bother.

     
  12. iceaura Valued Senior Member

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    We would seem to be in agreement, then, regarding the relevance of the negative second derivative in the population growth curve.

    Move on to the thread topic, predictions of environmental doom? My assertions and observations and so forth are posted, repetitively, above, and await response from anyone interested.
     
  13. adoucette Caca Occurs Valued Senior Member

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    Why?
    You constantly post lies and then when you are shown they are lies, you just move on like nothing happened.
    Debating you is like kissing your sister.
    Only less satisfying
     
  14. iceaura Valued Senior Member

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    ? You seem to want to talk about actual, specific models of population growth - very complex combinations of functions, replete with assumptions about the reality modeled. But you refuse to discuss the assumptions. Why?
    Here, for instance:
    If you assume a plateau, rather than a decline, sure - but the "point" involved is a population: a larger one than we have now.

    The thread question (population bust aspect) is: Can it be achieved and sustained, before disaster strikes? Or to put it another way: what's left out of the models that yield plateaus without large and rapid declines some day far in the future, and does it matter?
    It will all come true if you click your heels together three times, and shut your eyes.
     
  15. Trippy ALEA IACTA EST Staff Member

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    No, we are not.

    To elaborate further - what we are in agreement on is that your 'technical quibble' is nothing more than that, because the models or analogs that it describes are irrelevant to the discussion, and here we seem to differ on the reasons why they're irrelevant.

    What's posted above is a series of irrelevant distractions, that some might consider trolling.
     
    Last edited: May 22, 2011
  16. Trippy ALEA IACTA EST Staff Member

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    10,890
    I have discussed the assumptions, you just haven't recognized or understood it.

    Soem point in time, or some point in the furture. And what, precisely is your point here?

    You seem to be making an assertion against something that hasn't actually been said, and contradicts several things that have been - neither myself, nor fraggle rocker, nor adoucette, for example, are arguing that the population has reached a plateu.

    The information available suggests probably, yes.

    You seem to be concerned about future rapid declines, you've bought it up on several occasions, why is that?

    You do understand, don't you that if the currently observed trends - the observed relationship between prosperity and fertility, for example, continue (you have produced zero information to suggest otherwise) then any population must enter a state of decline before even re-equilibriation can occur. And it doesn't even neccessarily have to be about lack of food, or fresh drinking water either - all it takes is a couple of generations of people having on average < 2 kids (assuming zero infant mortality and the like).
     
  17. iceaura Valued Senior Member

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    Aside from my point about the irrelevance of second derivatives without actual mechanism (their various mathematical properties guarantee nothing of relevance), made in debunking their use in the false reassurance of the "wealth effect", no information presented in this thread so far even bears on the question.

    None of your contributions, even after your backfilled corrections, none of the stuff about second derivatives other than their indication of possible boom curbing by as yet unconsidered mechanism, bear on the OP at all - for example.

    Baffled, I am.
     
  18. Trippy ALEA IACTA EST Staff Member

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    Quit trolling, you've been provided with several mechanisms, you've just refused to discuss them.

    No false reassurances have been made.
    Prosperity isn't just about wealth, but wealth can be used as a measure of prosperity.
    It has been directly addressed.

    More trolling.
    I have made no backfilled corrections.
    My claims have not changed. The worst I am guilty of is assuming that you're capable of retaining the context and flow of a conversation.

    The mechanisms have been precisely considered, and are directly relevant to the OP.

    Yes, I imagine you are.
     
  19. iceaura Valued Senior Member

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    Naming is not addressing, nor does handwaving about second derivatives - (even if you were to fix the errors of application and interpretation, such as the assumptions of plateaus where none exist, you still lack mechanism) - and prosperity or wealth or whatever you are actually considering in your apparently suggested employment of (giving you the benefit of considerable doubt) median per capita GDP, even invoke (let alone consider) actual mechanism.

    So that the reassurances visible in this thread, at least in the early stages before the pro forma invective barrage, about a foreseen leveling off of the human population boom (specifically and clearly projections of a plateau, or at worst shallow and calm decline, rather than the boom and crash of the doomsayers' visions), are based in nothing but a vague reference to "current trends".

    Now if mechanism is to be considered, "current trends" does not refer to properties of some fitted curve. The curves, and any of their properties, are not mechanisms.

    So we have a couple of possibilities for actual discussion: we have the assertion, now cleared of bogus mathematical incantations (? please?), that a general increase in per capita GDP will produce a natural leveling of the population short of environmental catastrophe - that the current boom is not overshooting and will not overshoot before plateauing at some sustainable level, that the effects of growing wealth will overtake the effects of increasing numbers.

    Against this we have the doomsayers' observations that such does not appear to be happening - that the population has grown and is growing too fast, is chewing into its resource base, and that nowhere has a sustainable population been achieved or even approached at a reassuring rate (the allegedly and dubiously plateaued populations of places like Germany seen to be artificially circumscribed and ecologically not relevantly isolated).
     
  20. Trippy ALEA IACTA EST Staff Member

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    No I don't.
    And it has been addressed, not just named.

    Multiple specific mechanisms have been addressed.

    No, they aren't.

    Strawman hypothesis - not the claim that was being made.

    No bogus mathematical incantations were made - you just ran into trouble when you took statements out of their context.

    The rest of what you describe tends to be the observable pattern, aside from one point, there tends to be a small negative adjustment after the boom - it's visible in the UK age pyramid, for example, followed by a much subdued 'echo boom'.

    Are you still banging that drum?

    Time to support your claims - either provide one single shred, just one iota of evidence, that the growth in population observed in Germany between 1985 and 1995 was caused by anything other than one time political pressures influencing immigration (some of which happen to be some of the most important events in modern world history).
     
  21. iceaura Valued Senior Member

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    On this thread? A little, by me. But that's not a discussion.
    I quoted several, by you and Fraggle. Your subsequent partial corrections were appreciated, but the consequent invalidation of the original support claimed remains unrecgonized.
    It's my relevant issue on the thread, now that the math has been laid to rest (and before, actually, but there's no stopping you guys on a roll). I keep trying to bring it to discussion - you don't have to address it, of course.

    But I think it was caused by exactly that, and have made no claims otherwise.

    I wouldn't be surprised if future growth in Germany's population were similarly motivated. And I wouldn't be surprised if that growth were similarly substantial.
     
    Last edited: May 25, 2011
  22. Trippy ALEA IACTA EST Staff Member

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    Not just by you.

    The original support has not actually been invalidated, more-over, the point remains that the models that you bought into the discussion were deemed to be irrelevant, by you.

    You seem to have confused yourself, to be expected when you fail to retain context, I suppose.

    And yet you fail to recognize the significance of it in relation to the plateuing of Germany's population - it directly implies that if current socio-political trends continue, then the current trends observed in population chart will continue.

    In otherwords, you agree that, excluding exceptional circumstances, for example a change in German foreign policy regarding asylumn seekers, that the german population will continue to plateu, and may even begin a gradual decline.
     
  23. iceaura Valued Senior Member

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    Now we're getting somewhere - at last we approach the issue of what - exactly - must be assumed to begin to "continue" to maintain Germany's population at something resembling a plateau.

    What "socio-political trends" are we presuming to be essentially permanent features now, and how do they maintain a plateau - as opposed to, say, creating cycles of growth and pause, or worse boom and bust?

    We note that never before in the modern past (since the advent of Western industrial civilization) has the population plateaued for even one complete generation.
    On the one hand, there's nothing "exceptional" about changes in political circumstance - rather the rule, than the exception, for many generations now. On the other hand, the effects of generations of unusual stability in such matters are not obvious - we have no modern, industrial economy experience with such a strange situation. These little flat spots in the growth curves are being produced without such stability.

    In addition, the contribution of such closure of the German demographics to the larger (continental, global) population is uncertain - the population of Turkey will be affected, for one. We might compare the effects on Mexico's demographics if the border with the US had been closed thirty years ago.

    And finally, the reassurance taken from speculatively projecting such hiatuses in growth as Germany's into several generations of the future is a false one - not only are Germany's type of circumstances unavailable to the majority of the world's population, but the entire argument begs the question of overpopulation-caused environmental dooms, which are presumed by the doomsayers to depend on the actual population level reached and its effects.
     

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