Wikipedia:Reference desk/Archives/Humanities/2012 March 15

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March 15

producer to consumer ratio

I'm not sure how to frame this, so forgive the laymen's terms. Is there a formula to determine how many people are actually necessary to sustain modern life? What I mean is, I don't grow my own food, weave my own cloth or drill my own oil well. Yet someone out there has that skill. Now that we have 7 billion people on the planet, is there a formula for a producer to consumer ratio, how many people do we each depend on to pick tomatoes, build apartments and fish for us, while we're each putting our own skill into the equation? Jacques Cousteau said world population should somehow be reduced to something like 35,000 or some scary low number like that. Were something catastrophic to happen to Earth a la John Cusack movies, how many would need to survive so we don't T-rex out? Okay, that's a bunch of questions...--Kintetsubuffalo (talk) 15:43, 15 March 2012 (UTC)

Sustaining modern life and avoiding extinction require very different minimum numbers. The number required to sustain modern life would obviously be fairly close to the present population. Even withdrawing 5-20% of the workforce from employment during the recent (current) economic downturn has caused a drop in the median standard of living in the developed world. (This ignores the scenario of peak oil, in which the decline in the petroleum supply will force a decline in standards of living regardless of population.) However, the minimum number needed to avoid extinction would be quite small, certainly less than 100,000. The exact number would depend on the genetic diversity of the relict population. A very genetically diverse population of a few dozen would probably suffice. If the only humans left living were, say, (genetically homogeneous) Icelanders, you might need several thousand to avoid inbreeding depression. Marco polo (talk) 16:51, 15 March 2012 (UTC)

Wow, that's really thorough, thanks! Go back for a moment to "fairly close to the present population... has caused a drop in the median standard of living in the developed world"-well yeah, 20% would cause that! But the 5%, given even industrialized nations' chronic unemployment? You seem to be really up on this-can you suggest articles, on WP or elsewhere? Thanks!--Kintetsubuffalo (talk) 17:08, 15 March 2012 (UTC)

I'd also point out that over time these numbers will change dramatically. The percentage of people involved in the agricultural production of the United States, for example, has been steeply declining for the last century. The reasons for this are many: mechanized agriculture and increased crop yields allow fewer people to produce a lot more. (This doesn't take into account importing agriculture, which complicates things.) Certain forms of production probably require the same number of people as 100 years ago, but I suspect many do not. --Mr.98 (talk) 17:13, 15 March 2012 (UTC)

Mr. 98's first sentence here raises a very salient point: People who predict the sort of things that the OP is talking about invariably get it woefully wrong, because they always drastically underestimate the effects of technological and social change on the ability of humanity to adapt to growing needs. Ever since Thomas Robert Malthus predicted that the Earth would run out of food supplies faster than people would stop making more people, the catastrophe he predicted has yet to come to fruition, largely for two reasons:

• Agricultural production growth continues to outpace predictions because technology continues to improve production rates. Malthus, and those like him, assume that growth in agricultural production comes largely from simply planting more crops on more land, but fundemental changes to the way food production occurs results in more food being produced by less workers on less land than before.
• Population growth doesn't occur exponentially in fully developed countries. The exponential growth models work for developing countries, which essentially described the entirety of the world in Malthus's time. Today, however, we more fully understand what is often called the Demographic-economic paradox, which is that as countries become more economically and socially advanced, fertility rates actually decrease dramatically. There's lots of explanations as to why this might happen, and such discussion is out of scope here, but suffice it to say that when a society reaches an advanced socio-economic state, population growth slows dramatically.

The result is, for answering the OP's question, there may very well not be any lower limit to the number of producers to consumers, or at least, so low a limit as to be practically zero. As technology advances, more processes become automated, so less people are needed. One could envisage, for example, a time in the future when most food is never touched by human hands, where the entire process from farm to plate is handled by machines, and where humans are only needed to maintain and tweak the machinery. The labor of an insignificant few dozen people could be used to feed millions. Furthermore, with the "paradox" I cited above, we may be heading for a natural population equilibrium, once all of the planet reaches the highest levels of socioeconomic development, it is quite likely that the Earth's population may level off at some point. Which is not to say that such a society will be a paradise. To understand one current mode of thinking on social and demographic problems we may face in the future, the OP may want to do some reading and research into what is called the Post scarcity society. Quite an interesting perspective on the issue. Malthusian thinking (which is what the OPs question is based upon) is unfortunately imbedded in our Zeitgeist, even if actual data seems to tell us that it isn't bearing out. Post-scarcity thinking may be the better way to approach understanding future problems of this nature. --Jayron32 18:29, 15 March 2012 (UTC)

Whilst possible a bit more general than human based the article Minimum viable population might be worth a read. Also maybe Effective population size may help. Judging by a bit of googling minimum viable population seems to be a popular description for what you're talking about so you might get some use through google with that term. ny156uk (talk) 19:42, 15 March 2012 (UTC)

Jayron has not mentioned the decisive reason why humanity has been able to avoid a Malthusian disaster. That reason is the more-or-less steady growth, to date, in the use of fossil fuels. Only through the use of fossil fuels was humanity able to shift from intensive agriculture, which employed most of the population yet produced yields low enough to limit that population to a level near or below 1 billion. Without fossil fuels, none of the technologies most crucial to population growth would have been possible (including mechanization of agriculture, synthetic fertilizers, mechanized transport of nutrients to urban populations, and even hygienic advances such as widespread water treatment and sewerage and many medical procedures). According to this report commissioned by the U.S. Department of Energy petroleum supplies either have peaked (reached a maximum of output) or will peak within a few years, after which oil supplies will decline. Other careful estimates suggest that other fossil fuels will likewise see a peak in production within a generation (25 years) or so, as the easy-to-extract reserves are exhausted. Now, it is conceivable that people will be able to make use of technology to prevent a Malthusian collapse on the way to a culture and economy with much lower energy demands. However, that culture and economy will almost certainly require a much larger percentage of people to be involved in physical farm work and other physical kinds of work since the total supply of energy available for humankind to harness will drop considerably. Renewable energy sources can help to cushion the energy loss but cannot come close to making up for the lost energy. Numerous books have been written on this topic, which has been largely ignored by the mainstream media, perhaps because exposing the issue would threaten profits or advertisers. One example of a book on this topic is The Party's Over: Oil, War, and the Fate of Industrial Societies. So, if the question is what it takes to sustain modern life, I think that the question has to be phrased in terms of energy supply rather than population. Marco polo (talk) 19:48, 15 March 2012 (UTC)

You haven't done anything except move the Malthusian argument to a different commodity (food to oil). The greater issue is whether or not humanity will be able to deal with the Peak Oil problem; I have seen no evidence that it will not; when economic realities make the oil-based economy unfeasible, existing but under-utitlized non-petroleum energy systems will take over. Will it be painless? No, but an oil-based Malthusian catastrope is no more or less likely than a food-based one. The assumption that the future of humanity is wholly dependant on what the present of humanity looks like is still at the heart of the "the world ends when we run out of oil" argument. It is still based on the "if nothing changes about the way the world is today"; and we should already be prepared for the fact that the world will change. --Jayron32 19:55, 15 March 2012 (UTC)

It's a question of what sort of technology you are willing to accept. It takes billions of dollars to set up a fabricating plant for modern computer CPU chips. It's hard to see how that could be feasible for a population of a few thousand people -- you'd have to charge the equivalent of a million dollars for an ordinary laptop. There are lots of other types of technology that can only be produced efficiently on a huge scale. Looie496 (talk) 19:58, 15 March 2012 (UTC)

The Toba catastrophe theory suggests that the worldwide human population was reduced to 10,000 individuals or even less, around 70,000 years ago. After the event, humans showed very little population growth for many thousands of years. The event also caused a "genetic bottleneck" which may account for the very narrow range of genetic diversity among homo sapiens compared to other primates.

Despite other people above suggesting modern life needs a very large population to be sustainable, I disagree. The world's population has doubled in my lifetime so far, largely through third-world population growth while the first-world population has in fact grown very little. I don't recall us lacking the trappings of a modern life when I was a child and there were only 3.5 billion humans. Astronaut (talk) 14:14, 16 March 2012 (UTC)

Actually, I haven't really shifted the Malthusian argument from food to oil. My argument is that oil (and coal and gas) is food. In fact, I am defending Malthus. Malthus did not foresee the massive growth in the application of fossil fuel. If that had not happened, Malthus's predictions would likely have been borne out. Now that the use of fossil fuel is approaching a peak, we will finally see a real test of Malthus's argument. I agree with you that there is a chance that technology will allow us to avert a demographic disaster. (Though I don't see anything like the urgent development and application of such technologies that is needed to avert one.) I don't agree that non-fossil energy sources have a remote chance of providing amounts of energy similar to fossil fuels. There are sharp limits on the availability and collection of wind, hydropower, geothermal, and various tidal energy sources. We have already approached the limits of hydro. Solar energy is of course vast, but all but one of our technologies for collecting solar energy are either themselves energy- and resource-intensive and therefore virtually impossible to develop on the necessary scale in a world where conventional energy sources (and other resources) are scarce and declining. The one solar technology that is not energy or resource-intensive, biomass, competes directly with food for space on the planet's surface. Of course, there is a possibility of harvesting biomass on land (or water) not usable for raising crops, but doing so would have unpredictable ecological consequences, apart from a predictable disruption of the climate and reduction of the planet's carrying capacity. To sum up, the only technologies that offer a hope of preventing a Malthusian die-off would be technologies that would allow humanity to survive with much lower energy inputs. As I've said, some such technologies exist, but scaling them up to sustain the world's population would entail a massive effort over the next two decades or so, and there is no sign of such an effort. A successful effort to put these technologies in place would entail a radical transition to a culture and economy very different from the ones we have now and involving much more physical labor. In essence, modern life is unsustainable even in the best scenario. Marco polo (talk) 14:50, 16 March 2012 (UTC)

bette davis

not really question but i'm watching a movie called "The great lie" made in 1941 and is not listed in her credits — Preceding unsigned comment added by 173.60.125.245 (talk) 23:14, 15 March 2012 (UTC)

Thanks. Now it is. I doubt that's a complete filmography :(. See also The Great Lie --Tagishsimon (talk) 23:18, 15 March 2012 (UTC)

Yea, I suggest IMDB for a complete filmography. Wikipedia isn't meant to be comprehensive. StuRat (talk) 02:59, 16 March 2012 (UTC)

That's a minor untruth. It's listed in the complete Bette Davis filmography. Bette Davis has a selected filmography, and I'm not convinced A Great Lie belongs among her major films. Clarityfiend (talk) 03:29, 16 March 2012 (UTC)