Talk:Malthusian catastrophe

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[edit] Exponential growth annual growth chart

It says next to this image "The annual increase graph does not appear as one would expect for exponential growth. For exponential growth, it should itself be an upward trending exponential curve whereas it has actually been trending downward since 1986. " I don't think this is quite correct. In an exponential growth situation, the annual growth rate (given in % like the graph), should remain constant, not trend upwards exponentially. Comments? Ed Sanville 21:33, 22 April 2006 (UTC)

This is because on 27 March, Casito edited the image file because "Excel Graphs look unprofessional", and changed it to percentage growth because it is "more useful", but didn't adjust the description; the original image, which you can still find here showed absolute growth. Either the image should be converted back to absoute growth rate, or the description adjusted accordingly. For the time being I've adjusted the description to correct the inconsistency, but don't take that as a vote either way. (Worryingly, this image edit did not trigger my watchlists, even though that image was on my watchlist.) -- Securiger 11:11, 24 April 2006 (UTC)

I have completed the edits I planned to make to this page. I would be interested to see any comments.

Buzz Bloom

Some of this article's information has been moved to Neanderthals Bandits and Farmers or Cannibals and Kings articles where it more rightfully belongs. The remainder contained some pretty basic errors (e.g. supply and demand) and has been mostly rewritten. I am pretty confident about this, but if you think it was correct we can discuss it here. User:H7asan

H7asan

We obviously have a disagreement regarding the relevance of "Beyond the Limits". I found the entire book exactly on the point. It deals with the exhaustion of food (and other resources) as a result of unconstrained population growth (as well as the unconstrained growth of consumption). I definitely think this book should be referenced from a discussion of neo-Malthusean theory. Why do you think otherwise? Also, what is the proper mechanism for getting a disagreement of this kind resolved?

By the way, I thought your moving of the discussion about the Harris and Tudge books to their own pages was a good idea.

Buzz Bloom


I have nothing against the Beyond the Limits book. (Actually I know nothing about it.) My problem was with the article which was empty. User:H7asan

I plan to remove the two paragraphs beginning with "Another problem is that there is no strong evidence ... " including the two graphs. This discussion is irrelevant to the topic of the Mathusuan catastrophe. Malthus never described population growth as being exponential. He said the growth would be expoential in unchecked, and then only until a subsistance level was reached. Growth of a population until a subsistance level would correspond to what Securiger describes in the current text I plan to remove as a Logistic curve. All that the curves show is that the current trend of world population from 1950-2000 may be begining to reach a new limit of a kind that Malthus discusses: use of contraception, which Malthus called a vice.

I put this notice of intent here to elicit comments or alternative suggestions before doing it.

I also plan to edit the remaining material in the "Non-occurrence of the catastrophe" section cbecajuse I think it un fairly represents the state of the world at the end of the 19th century, which the anthropoligist Marvin Harris describes as one of approaching catastrophe as predicted by Malthus. The section should discuss the innovations of the twentieth century that offer opportunities to avoid the catastrophe, or only postpose it. From this perspective, I would change he title of the section to "Postponement or non-occurrence of the catastrophe".

I also elicit comments or alternative suggestions regarding these intentions.

User:BuzzB Feb 28, 2004

I disagree with both proposed edits, quite strongly. Firstly, the paragraphs beginning "Another problem is..." are highly relevant. Malthus proposed a particular theory, which was essentially premised on three claims, one of them being the idea that a human population undergoes geometric growth if unchecked. Malthus' Essay has been disputed by many, and one major point of disputation - indeed one of the few points, pro- or anti-, that bothers to look at empirical facts - is that there is absolutely no evidence in support of this basic premise. It was pointed out as soon as the Essay was published, and continues to be pointed out today; if you like you can propose hypotheses to explain that fact away, but simply removing all evidence of it would severely bias the article.
Equally, we could point out that there is no evidence that food supply increases arithmetically, and that in fact it patently does not. One of the nicer summaries is this, written by Hazlitt in 1822:
All that is true of Mr Malthus's doctrine then, is this, that the tendency of population to increase remains after the power of the earth to produce more food is gone; that the one is limited, the other unlimited. This is enough for the morality of the question: his mathematics are altogether spurious.
Secondly, you propose to edit the remaining material in that section, because you claim that it "un fairly represents the state of the world at the end of the 19th century, which the anthropoligist Marvin Harris describes as one of approaching catastrophe as predicted by Malthus". Huh? That section doesn't even discuss the end of the nineteenth century! If you meant "end of the 18th century", which is mentioned, then of that time it says "At the time Malthus wrote, most societies had populations at or near their agricultural limits" - which is not contradicted by your point!? (Although there is plenty of evidence to believe that that statement is also somewhat exaggerated).
I should point out that when I get time to do it justice, I plan to make extensive additions to this article, which in my opinion is currently very shallow and unencyclopedic. It currently represents the shallow, ill-defined, handwaving version of the Malthusian theory that is frequently dragged out in the pub or at dinner parties in support of some political argument or another. But in fact Malthus had a much more complete theory than is represented here, which was one of the seminal theories that gave rise to economics. (Although there is very little of the detail that is still widely accepted.) We need to work in its rôle in the development of economics. Additionally the current article needs to mention Wallace, who had the idea first. Oh, and it also doesn't even mention the basic Malthusian idea that increased food supply automatically generated increased population until everyone was starving again, which segues into the rôle the theory in had in justifying the oppression of the poor in nineteenth century politics - again from Hazlitt:
The instant, however, any increase in population, with or without an increase in the means of subsistence, is hinted, the disciples of Mr Malthus are struck with horror at the vice and misery which must ensue to keep this double population down; nay, mention any improvement, any reform, any addition to the comforts or necessaries of life, any diminution of vice and misery, and the infallible result in their apprehensive imagination is only an incalculable increase of vice and misery, from the increased means of subsistence, and increased population that would follow. They have but this one idea in their heads; it comes in at every turn, and nothing can drive it out.
Securiger 11:28, 1 Mar 2004 (UTC)

I have extended the graph using the same data source, out to the years 1800-2005. Unfortunately, there seems to be some problem with the new image. Sometimes it appears when the article is displayed, and sometimes I see only a reference to an image. I have posted a query over at WikiMedia, and I hope to have it resolved in a day or two. Meanwhile, if you are looking for the image, please have some patience! --Aetheling 16:53, 30 September 2006 (UTC)

[edit] Graph of World Population

Hmm. I just wanted to object to a few things:

  • The World Population graph is described as "clearly... close to linear". Really? To me it looks "clearly curved". (In fact, I think I see evidence of the logistic curve, but that could well be spurious.) As alluded to in the article, 50 years is an awfully short time to get a good idea of how human population levels are changing. In fact, graphing the data from 1804-1999 given in the first external link at that point in the article, would give a strong impression of exponential growth. Yes, maybe we're starting to see the beginning of the "slowing down" in growth that's predicted by the logistic model, but it's relatively early in that process, IMO, so I would be very hesitant to claim that the growth is no longer exponential — certainly not based on the data given here. (dcljr, continued below)
    • Yes, graphing the 6 points 1804-1999 does look closer to exponential (see below) - but the data prior to 1950 are extrapolations or approximations, based partly on the assumption of exponential growth prior to 1950 (and of course data after 2004 is purely extrapolated with some unstated model). Only the data highlighted in blue are based largely on actual census counts. (In any case, it looks closer still to two linear segments with an critical point near 1960). So the reason for concentrating on the last 50 years is because that is the sole period for which we have reasonably reliable data. And when you graph that real data, you get something that offers little support for the common assumption that "it's obviously exponential". Also it was not stated that it's "no longer exponential", but rather that there is no strong evidence that it ever has been. In fact it could be a very slow exponential, or maybe a very slow logistical, or perhaps linear, or quadratic - the point is we really don't know, and at any rate it certainly isn't a simple function. But at least the reason for choosing this period should be clarified. (Securiger)
      Image:Extrapolated world population history.png
      • Hmm... Part of the reason it might look closer to two linear segments is because the interpolating curve is (I assume) a cubic spline (and there's no point for it to go through between c. 1805 and 1925). Anyway, I agree with the rest of your paragraph. - dcljr 22:53, 7 Sep 2004 (UTC)
  • Note that the plot of World Population Increase suggests that the rate of increase may actually still be going up, perhaps even (approximately) linearly (you always have to expect short-term fluctuations from the overall trend), which would imply quadratic growth. (dcljr)
    • How do you figure that? Apart from two years, it has been going down every year since 1987 - which is a third of the period for which we actually have reliable data! (Overall, there has been downturn in the growth rate for 26 of the 54 years considered.) (Securiger)
  • The sentence that begins "Also the rate of increase should increase, whereas, of the increase between 1960 and today, five-sixths occurred in the early 1960s", aside from being confusing, is completely misleading, since a mere glance of the Increase graph shows something highly unusual happening in the years 1957-1962, resulting in a lcoal minimum in 1960! That dip in the graph is the only reason the statement above is true (to the extent that it is). (dcljr)
    • I'll try to rephrase the sentence you find confusing. The point is that in a positive exponential, the first difference (and second difference, and all other differences) is also a positive, upward trending exponential. Thus when you get a true exponential growth curve and plot the differences between years, that rate-of-growth curve is itself an upward curving exponential. The rate-of-growth curve for human population clearly does not look like that at all. This is seen even more so in the 2nd difference curve (below), which however I would not include on the main page because second differences are heavily affected by noise. If population was exponential, the second difference curve should also be exponential, in fact it has a lot of noise oscillating around zero but with an overall downward trend. As for the statement which you claim is "completely misleading", umm, your "objection" agrees almost exactly with the point and meaning of that sentence: if we were looking at exponential growth, most of the growth would be recent, but in fact most of the growth is due to "something highly unusual" happening back then - the big dip from '57 to '60, and also the huge surge from '60 to '63. And even if we interpolate the years '57 to '63 to remove this curious feature, 75% of the growth increase between 1950 and the peak year, 1990, occurred in the first half of that period. This is just not at all consistent with a positive exponential growth. It seems I need to make some clarifications on why this chart, and the data it represents, are wholly inconsistent with the implications of exponential growth. (Securiger)
      Image:Population 2nd derivative.png
      • Maybe I misunderstood your purpose of pointing out the circa-1960 thing. I don't know. In any case, I wouldn't read much into the data of around that time. The "hiccup" might just be "noise" or might be due to a completely administrative cause (a change, say, in how censuses were taken or recorded in one or more large countries at the time — who knows?). I think most of our "differences" can be summed up by the following statement from the article: "...short-term trends, even on the scale of decades or centuries, do not necessarily disprove the underlying mechanisms...". I've been taking a much more long-term perspective, figuring that things like the 1960-ish "hiccup" and the "decrease in the increase" since 1986 are likely short-term deviations from the overall pattern over centuries (which is essentially unknowable anyway, but at least an exponential [and logistical] model has some theoretical basis). Anyway, I think both of us can agree that in the last 50 years or so the trend has not appeared to be exponential. On a completely different note, it would be interesting to consider (not in the article itself — or even here, necessarily) what role (tele)communications and transportation plays in all of this. Might population growth be "stabilizing" (2nd derivative graph above) as a result of the increased interconnectedness of human populations? Perhaps that's the reason behind the "critical point" of around 1960? - dcljr 22:53, 7 Sep 2004 (UTC)
  • Finally, I think the correlation coefficient is a pretty useless measure of anything in this context; someone should do an appropriate statistical test on the yearly data instead (I suggest an F-test to see whether an exponential term is needed over linear [intercept and slope] terms, and possibly an approximate lack of fit test). - dcljr 08:00, 6 Aug 2004 (UTC)
    • Why do you think it is useless here? r2 is supposed to measure the fraction of the variability in y explained by the function of x - in this case, a linear model and exponential one explain the variability about equally well. I don't understand what you mean by "F-test to see whether an exponential term is needed over linear", but an F-test finds no significant difference in the residuals from linear and exponential models. Securiger 16:58, 7 Aug 2004 (UTC)
      • Why is it useless? Because an exponential with slow growth can look linear and have a correlation close to 1! As for r², the article mentions the correlation coefficient not the coefficient of determination. Although obviously they're computationally the same in this case, the author was using it specifically to indicate linearity. In any case, even if you grant that "practically speaking" the correlation is close to 1, consider what "practice" we're putting this information to: we're using these models to predict population levels far into the future (sometimes as far into the future as we have "reliable" data in the past, in fact — see above graph) and there can be a big difference between extrapolation using a linear model and one using an exponential. (Of course. That's why we're discussing this in the first place.) Oh, and I meant an ANOVA "F-test" for testing whether a coefficient in a regression model is zero (as opposed to an "F-test" for testing the equality of two population variances). I should have been more specific. I'm not sure what "F-test" you did. - dcljr 22:53, 7 Sep 2004 (UTC)

[edit] Depletion of resources.

I think these things should be included because they strongly effect what decisions should be made regarding Malthusian theory. I find it impossible to argue with or doubt the basic theory. Almost the only requirements for its applicability are that life exists and there is no centralized control. What is in question are the time scale and the nature of the catastrophe. Both of these are strongly effected by pollution and resource depletion, especially energy and farm land. One can consider food the "fuel" of non-industrial man, so energy is the modern equivalent.

The only way I feel I am being pessimistic is that nuclear (breader fission and/or fusion) power may well be able to replace fossil fuels with acceptable pollution and hazard, but no-one is sure of that. Anyway it can't support the kind of increase in energy consumption we are seeing.

David R. Ingham

[edit] Citations Needed

There is no cite given for the following assertion:

In fact, currently, food supply per person is several times higher than when Malthus wrote his essay

[edit] Only showing to 1950 in the chart

I read what was discussed before, and I still think it is misleading to only show data from 1950-2000. Regardless of the precision of the data before 1950, the numbers can still be shown to be in the right ballpark. (One reader commented that the data before 1950 were often approxomations that, in part, assumed exponential growth - but one can not possibly assume linear growth, or there would have been no people before 1900! And the numbers for earlier dates are based on real data, not merely assumptions.)

It's obvious that the period from 1950 to 2000 looks much more linear than, say, 1750 to 2000, and gives a misleading impression. The correct answer is, as has been said, that world population appears to follow a more complex function than simple linear, exponential, or quadratic growth. So why show only the select portion that appears linear? – Quadell (talk) 13:47, 10 October 2005 (UTC)

Since there has been no discussion for 2 weeks on this, I'm going to change the article. – Quadell (talk) 15:19, 23 October 2005 (UTC)

[edit] An Inaccurate Interpretation

When you say:

"[Malthus] predicted that population growth would eventually outrun food supply,"

(this being one of many statements you've made in support of your interpretation) you seem to be claiming that Malthus was describing (and predicting) a future catastrophic global event - one that has yet to occur. That is not what he was saying, at all.

Malthus posited a doubling of world population every 25 years under ideal conditions (no shortage of food and none of the "positive" constraints of, for example, war and disease). It is wrong to assume that Malthus actually thought the world population would double every 25 years until some future event in which there would not be enough food to sustain the population. (Given his ideal conditions and a population at the close of the 18th century of 1 billion, the world population would now be in excess of 250 billion.)

What he predicted was not some apocalyptic event but ongoing catastrophes playing out simultaneously in localized areas all over the world, wherever and whenever any group of people could not sustain themselves because their population had outrun the local area's food production capacity. His intent is quite clear in his statement (when discussing the American Indian):

"Yet, [...] the effort towards population, even in this people, seems to be always greater than the means to support it." [emphasis added]

It is also implicitly clear that when Darwin found in Malthus' essay the mechanism that drives evolution - a constant competition for survival due to limited resources - he didn't think Malthus was predicting some future global catastrophe.

Malthus was addressing the idea of utopian societies gaining popularity at the time he wrote his essay. The point of his essay was to show that there could never be a population free from poverty and hunger and, therefore, the dream of a utopian society was just that - a dream. While your point that food production is now far greater than Malthus could ever imagine is true, what Malthus was saying remains valid. There are more people living in extreme poverty today than there were people (in total) at the time Malthus wrote his essay.

Paul Pomeroy 06:14, 24 December 2005 (UTC)


I was going to make those very points (see above) about the logistic curve behaviour not contradicting Malthus's ideas, i.e. that he did not predict exponential growth but rather a tendency towards it, always modified by "checks", which is precisely where the logistics curve comes from. But then, why hasn't that change yet been made?

I'd also like to draw attention to [Nassau Senior]'s work on wages, which has some of this thinking behind it. The particular point I want to bring out is his idea that machinery could theoretically compete with people for food, if only it needed fuel that drew on the same resources - which using more renewable fuels might soon cause. PML.

[edit] Population, WHEN UNCHECKED, increases in a geometrical ratio

Hi,

when discussing the correctness of the geometric growth assumption and Malthus' theory in general it's important to keep Malthus' exact words in mind: "Population, WHEN UNCHECKED, increases in a geometrical ratio". Since the late 18th century occured plenty of Malthusian' checks to the human population: wars and epidemics, unhealthy living conditions, still existing infant mortality, contraception and abortion etc.

Arguing that the Malthusian population model is void because we can't see a perfect exponential growth in the world population chart seems somewhat dubios; without considering the existence of checks (that, in Malthus' thinking, avoid, or delay, the "big catastrophe").

-- 212.144.193.196 12:01, 19 February 2006 (UTC)

user 212.144.193.196 is right on target. i wish she or he would get a name :) Anlace 21:16, 23 June 2006 (UTC)

[edit] Fertility Rate

There has been enormous decrease in female fertility worldwide and this is something that is not just specific to the west. The average worldwide fertility is now 2.59 (2.1 is the replacement rate fertility at which no population growth will occur in the long term). For instance the fertility rate in India is now 2.73. This implies that growth is not exponential since a constant fertility rate would be required for exponential growth. This is the reason for the UN estimates. A scientific approach (scientific does not mean environmentalist) implies that population growth must level off due to decreasing fertility. Therefore neo-malthusian theory makes no sense and has just been debunked. QED bitches.

the anonymous author above makes little sense. the birth rate of India for example would lead to tens of millions more people in that country in the next decades if the rate is left unchecked and death rates do not escalate severely. moreover there are many ways population growth can "level off" besides decreased fertility. thus the author above has revealed his or her inherent lack of scientific approach. Anlace 04:39, 2 July 2006 (UTC)

That assumes fertility does not continue to decrease and we have no reason to expect that will happen given that it has decreased from 6 to less that 3 worldwide from 1960 to 1990. You say India will continue to experience population increase. It will but at a slower rate which is completely inconsistent with Malthus. Showing an increase in population is not enough. You are required to show an exponential increase. A decrease from 6 to 3 definitely implies that growth is not exponential since exponential growth requires constant fertility.

i think someone is missing the big picture here. have you seen the "low" projections for india and many lesser developed countries (i am not considering India lesser developed by the way). the real issue is carrying capacity. do you honestly believe there is carrying capacity for these burgeoning billions when over one billion people today do not have safe drinking water? this is not a simple matter of sharing the wealth. we are simply living on a finite planet, whose resources are stretched thinly. wake up and smell the coffee. the catatastrophe is occurring now. by the way your credibility would grow exponentially if you would create an account :) Anlace 05:15, 2 July 2006 (UTC)
Carrying capacity is a variable in the Logistic curve, it is not part of malthus' original theory afaik. Kim Bruning 09:07, 20 July 2006 (UTC)

[edit] Logistic curve and lotka-volterra

They're already mentioned, but not emphasized. Could we maybe stress that there are currently improved population models available. Both these newer models *do* actually have malthusian style exponential growth for certain parameters. They just also have different behaviour under other parameters. --Kim Bruning 09:01, 20 July 2006 (UTC)

[edit] NPOV & Factual accuracy

The section on "is the catastrophe happening?" seems to have a Non-NPOV and perhaps even some factual accuracy. I just stumbled on this article and don't know enough to necessarily correct it all myself, but tagged the section. For example, the unsourced and original opinion that the UN study is "less scientific" than contradicting studies. There are weasel words/phrases like "numerous scholars accept...", "some analysts consider...", etc. I think the section has definitely been massaged to push a subtly apocalyptic point of view.--160.39.213.64 01:54, 27 September 2006 (UTC)

I did enjoy the bit about one lone economist suggessting that global starvation might not be inevitable! Most economists (and others with a half a brain!) regard theories of Malthusian catastophes as a 19th century goof, and comprehensively disproven! Neo-Malthusianism is up there with those who believe that reading the Bible backwards reveals Satanic messages! --Nmcmurdo 19:02, 23 October 2006 (UTC)

I agree that the earlier version had some serious problems with bias. As time permits, I have been trying to improve this section with both text and figures that let readers make up their own minds based on the most impartial and accurate graphics that I can devise. — Aetheling 20:55, 24 October 2006 (UTC)

As first user states. There are lots of NPOV issues with that section. Whoever authored that section was determined to reject all notions that the Malthusian Catastrophe is shoved back/not happening at all. Then again murdo, isn't it a bit personal to talk, ad hominem, to the Neo-Malthusians? We sure could use a little tact everywhere in Wikipedia. Pasonia 03:31, 18 November 2006 (UTC)

True. The way I heard it, the world food supply is more than enough to comfortably sustain the entire population, and famine is due mostly to politics and poor distribution. Vultur 9:48 PM, 16 December 2006 (UTC)

there is no question that more sourcing is needed on this article (along with 99 percent of all wikipedia articles}. Vultur, the way you "heard it" is factually in error. the world food supply is presently being produced by unsustainable agricultural methods. in some of the biggest production areas (eg great plains of USA and north China plain) groundwater is being exhausted. there are countless other factual examples of the fact that food production is not foreseeably adequate...let alone adequate drinking water. thus i hope the zeal expressed above will translate into acquiring fact based sources. regards. Anlace 15:31, 17 December 2006 (UTC)

[edit] Malthusian catastrophe in popular culture

Maybe this article is asking for a "Malthusian catastrophe in popular culture" section, as popular on many other articles? To seed such a section, here's a piece of trivia: the Guardians of the Universe, from DC Comics, originated in a planed named Maltus, and were called Maltusians. Some of them evolved into the Guardians and left for Oa, while most stayed behind, and were later depicted as much less advanced than Earth, presumably due to Malthusian effects. It may be that the name is only a coincidence, and as such I'd rather not touch the article, but I believe it's intentional. I'm sure other people can remember lots of other pop references. LaloMartins 05:01, 12 October 2006 (UTC)

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