- Hubbert
- Mar 25, 2007
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At a time of universal deceit, telling the truth is a revolutionary act.
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hey guys
if you're going to call someone a Malthusian, you might as well know what you're talking about
let's take a peek at Overshoot: The Ecological Basis of Revolutionary Change together
quote:
Chapter 8 Ecological Causes of Unwelcome Change
Biotic Potential versus Carrying Capacity
In the next seven generations after the English clergyman-scholar Thomas Robert Malthus came to the dismal conclusions expressed in his 1798 “Essay on the Principle of Population,” millions of Britons emigrated to the New World. Nevertheless, during that time the resident population of Great Britain doubled, doubled again, and almost doubled a third time!
One contention in Malthus’s essay became widely known: “Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio”1 Throughout the essay Malthus was referring to human population, and by subsistence he meant food. As we shall see, these conceptions were unduly narrow. But the really basic Malthusian principle is so important that it needs to be restated in the more accurate vocabulary of modern ecology. It states a relationship of inequality between two variables:
"The cumulative biotic potential of the human species exceeds the carrying capacity of its habitat."
No interpretation of recent history can be valid unless it takes these two factors and this relation between them into account, No one can truly understand the intensification of competition unless he grasps this principle. People whose political, religious, and ideological perspectives cause them to ignore these two variables will not succeed, even with the best of intentions, in improving the human condition.2
The phrase “biotic potential” refers to the total number of offspring a parental pair would be theoretically capable of producing. The cumulative biotic potential of the human species refers to the total number of people that could result after a series of generatfons if each generation fully exercised its reproductive power. The carrying capacity of the habitat, of course, is simply the maximum number of living individuals the available resources can indefinitely support. It is limited not just by the finite supply of food, but also by any other substance or circumstance that is indispensable but finite in quantity. The least abundant necessity will be the limiting factor; it may or may not be food. For industrially developed countries it began to appear in the 1970s that the limiting factor might be oil, while in some places it was water. It could be some other necessity.
For most of these seven generations, people fondly imagined that somehow Malthus had been proven wrong.3 With the vast territorial expanse of the New World, and with new agricultural technology to exploit it, plus new means of transportation and trade, and improved organization, we expanded food production more than Malthus would have dreamed possible. Nevertheless, the Malthusian principle still held. We were only able to suppose it was mistaken because our exceptional circumstances (in the Age of Exuberance) made us commit two oversights. First, because the existing population was for the time being appreciably less than the world’s suddenly augmented carrying capacity, we did not see the human relevance of the carrying capacity concept. Second, we failed to think about cumulative population. Until lately there always seemed to be room for the increment we expected next year, or in the next generation.
Charles Darwin was more perceptive. He recognized not only the Malthusian principle’s truth, but also its significance. It was the key insight he needed to unlock the riddle of evolution—and thus to lay the foundation upon which his successors could build the science of ecology.4 In effect, Darwin saw that the adjective “human” was unnecessary in the Malthusian principle, for the principle was not limited to one species. Darwin’s version of it (recast here in the ecological language of today) was universal rather than specific:
The cumulative biotic potential of any species exceeds the carrying capacity of its habitat.
As a result, there is competition among the members of a species population for use of resources that are in short supply relative to their numbers. Not all competitors will succeed; not every individual will live through all stages of the life cycle. The population, pressing on its limited resources, will suffer attrition.
The attrition of the population will not be random, however. Darwin saw that, since there are differences between individuals, some competitors will have, advantages (however slight) that others will lack. Those with advantages will be somewhat more likely to survive to reproductive age; they will be somewhat more successful in mating, reproducing, and providing care for their progeny. Thus they will, on the average, leave more descendants than those with disadvantages. Moreover, Darwin saw that what traits are advantageous and what traits are disadvantageous will depend on what environmental circumstances the organism must cope with. Environmental selection pressures, he realized, need not alter the traits of any individual. Evolution happens when environmental pressures merely influence comparative reproductive success. By influencing the comparative abundance of a particular organism’s descendants, the requirements imposed by the habitat influence the future prevalence of that organism’s inheritable traits among the total population.
The fact that evolution does operate shows that the Malthusian principle is valid. So, too, does the fact that there are food chains. If each species did not overreproduce, then predation would always lead to extinction of prey, the predatory species in turn would starve, and life would long since have vanished from the earth. Herbivores do not meticulously wait for seeds to ripen and fall before consuming the plants that bear them. Carnivores do not generously abstain from eating herbivores until the latter have replaced themselves with progeny. Every species that serves as another’s sustenance can endure only by virtue of a reproductive capacity sufficient to compensate for such attrition. The persistence of life in a world where organisms consume other organisms confirms the Malthusian principle. To deny that principle, as we have naively done, is to deny evidence all around us.
With self-restraint, humans have been able sometimes to harvest such things as timber, fish, or other useful species on a “sustained yield” basis.5 This fact should be seen as evidence for, not against, the Malthusian principle. Depletion of such resources by an overly prolific human species was never the only predictable result of the Malthusian principle. We supposed it was because we thought about the principle too anthropocentrically. Sustained yields represent reproduction in excess of replacement by the resource species; the excess is then “harvested” by an exploiting species—in this case, Homo sapiens. If Malthus were so wrong, there would have been no sustained yields of anything. In every bite of our daily bread there is a reminder of the wheat plant’s ability to produce more seeds than required for its own replacement.
One of the great ironies of history has been the notion that our species was somehow exempt from a principle that manifestly applies to all other species. Malthus stated the principle of reproduction in excess of carrying capacity for man in particular. Darwin later generalized it to cover all species, and went on to discern its evolutionary implications. In the years since Darwin, most non-biologists seem to have smugly reversed Malthus by “slightly amending” Darwin’s generalized version—accepting its application to all species except one, ourselves, the very species about which the principle was first asserted.
To be sure, man does differ from other animals, for man transmits to his descendants a cultural as well as a genetic heritage. The cultural heritage is conveyed socially rather than biologically—by symbolic language rather than by chemical code. It is thus more readily and deliberately mutable.6 Its mutations can sometimes be mothered by necessity rather than by random accident, and perhaps somewhat more of them can be adaptive rather than lethal. But for some time there have been more and more signs that this cultural heritage does not exempt our species from the full ramifications of population pressure in a finite habitat. The ratio of load to carrying capacity can change culture itself. We had supposed our difference from other species exempted us. [...] Some of the wistful remembrance of earlier times reflected the wish that we could go on supposing.
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Environmental Brakes on Exuberance
Modern nations had staked their future on perpetual harvesting of supplies of non-renewable resources. Men now built with steel, concrete, or aluminum, rather than with wood. We had evolved into societies so large and complex that they required quantities of energy too vast to be supplied by contemporary crops of organic fuel. We allowed ourselves to become so numerous that we could not really grow the food we needed without enormous “energy subsidies,” augmenting sunlight and muscle power in agriculture with industrially produced chemical fertilizers and fuel-burning machinery for planting, cultivating, harvesting, shipping and processing.11 Americans thus were farming not only the great plains of Iowa and Nebraska but also the gas wells of Texas and Alaska and the oil wells of the continental shelf offshore. Even agriculture, the ultimate achievement in man’s development of the takeover method of carrying capacity expansion, had become converted to drawdown methods. The most “prosperous” nations were living on phantom carrying capacity but had not learned the concept. By using still more enormous quantities of energy for new occupations unrelated to agriculture, we put off recognizing that our population had outgrown its maintainable niches. Had people understood the ecological implications of the Industrial Revolution, it might have been seen not so much as a great step forward for mankind but, as we shall make clear in Chapter 10, as a tragic transition to human dependence on temporarily available resources.
To provide charcoal for iron smelting, the British in the eighteenth century had harvested their timber faster than it grew. Depletion of British forests led to increased coal mining.12 The need for pumping devices to remove water seeping into the mines provided the impetus for development of steam engines. Those engines could convert the chemical energy in a fuel such as coal into mechanical energy that could do useful work. In addition to working the pumps at the mines, other applications for steam engines were soon found, and they made great industrial expansion possible. Reliance on current photosynthesis (annual timber growth) was replaced by dependence on accumulated past photosynthesis (coal deposits). There was a rapid proliferation of coal-consuming machinery. As a result, Britain evolved an economy that traded British factory output for food and other agricultural products grown overseas. Those doublings of British population sine Malthus, and the exporting of British people to other lands around the world, were thus made possible by exchanging a way of life based on visible acreage for a way of life based on two levels of ghost acreage. By heavy use of fossil acreage, British industry produced the goods that gave Britain access to trade acreage.
So British exuberance since Malthus was no refutation of the Malthusian principle. By the drawdown method Britons merely postponed the day of reckoning. They lived beyond their energy income, harvesting timber on a faster-than-sustained-yield basis. Then they bought further time by exploiting ghost acreage—both overseas and underground. Despite such measures, only two hundred years after James Watt’s invention, the time Britain had thus bought seemed to be running out.13
Britain was the first nation to experience what economists came to call the “takeoff’ into supposedly self-sustaining economic growth. Long after the evidence had turned against the idea, the illusion persisted that a similarly brilliant destiny remained possible for all nations. This was partly due to economic theorists’ belief that the takeoff was a product of British accumulation of monetary savings in the form of profits from overseas trade.14 It depended, in fact, on the geological accumulation of energy savings in the form of coal deposits.15 In the last third of the twentieth century, although the vast majority of the world’s energy savings were still in the ground, the vast majority of the most accessible fraction of those savings had already been extracted and spent.
In the decades since World War II, all the leading industrial nations had plunged still more deeply into living on nature’s exhaustible legacy. Furthermore, they had committed themselves to technology that relied on the huge advantage petroleum had because it is liquid, whereas coal is solid. Consumption of petroleum products increased enormously, although petroleum was very much less abundant in the earth than coal. The relative share of energy obtained from coal diminished, and for some countries even the absolute amount declined. Many national economies made themselves deeply dependent on the continued sailing of growing fleets of supertankers. In the meantime, however, the volume of oil reserves discovered by each additional million feet of exploratory drilling was rapidly declining, despite expanded technical know-how. This showed us that we had already extracted and burned the most accessible supplies, and that the existing and still increasing rate of consumption would virtually exhaust even the less accessible reserves within the lifetime of people already living. The social repercussions were going to be staggering.
Many people refused to believe it, and national economic policies continued to be based on a myth of inexhaustibility. The coal miners’ strike in Britain in 1972 provided a temporary foretaste of the social and economic chaos that would have to come when a fuel-dependent world runs short of fuel.16 The Arab oil embargo the following year added a sharp reminder. Before retiring as prime minister, however, the characteristically indomitable Harold Wilson looked to future North Sea oil “production” as Britain’s economic savior—without acknowledging that salvation achieved by drawing down fossil acreage would have to be temporary.
Other mineral resources required by industry were also running shorter than people realized, were already probably operating as limits of the world’s rate of industrialization, and may even have been already limiting the productivity of existing industrial facilities. In the United States, for example, the number of pounds of copper obtained per ton of ore mined was by 1965 less than half what it was in 1925. Over those four decades, total copper production had almost doubled; this had obscured for an uncritical public the problems connected with a fourfold increase in ore extraction.17 Intensified efforts to secure such increasingly scarce resources could be expected to have serious social repercussions. Two cases will suffice to show the nature of the problem.
First, in Britain there were mounting worries over the likelihood that the remaining “amenity areas” of the country, such as Snowdonia National Park in Wales, would soon be devastated by strip mining for metallic ores needed by British and European industry.18 For many metals, the worlds richest ores had already been mined and smelted. Leaner ores had begun to be in increased demand. The leaner the ore being mined, the greater the volume of rock removed per ton of metal obtained. Even if the budget for mining operations were required to include provision for cleaning up and replanting after an area had been stripped, it would be impossible to restore the landscape characteristics that were imparted to Britain by the Ice Age. These were the features that contributed so much to the beauty of Britain’s northern countryside.
Second, in an effort to prevent white minority-ruled Rhodesia from establishing its independence in disregard of the full rights and aspirations of its large black majority, the United Nations had imposed economic sanctions upon that country. UN member nations were obliged to refrain from importing Rhodesian goods. But, faced with difficulty in obtaining from anywhere else (except Russia) adequate supplies of chromium needed for certain alloys, the United States government chose in 1972 to stop complying with the UN sanction. American firms resumed importing Rhodesian chrome.19 The American government decided to permit this in spite of strong internal pressure against giving aid and comfort to a regime internationally branded as racist.
If, as these examples show, advanced industrial nations with humane democratic traditions were thus pressed toward actions deeply deplored by many of their own citizens, it was clear that national economies were already feeling the pinch of ecological limits. These limits were the ultimate basis of some of the most revolutionary changes in our lives, particularly the rising sense of post-exuberant despair and oppression. The number of resources upon which our way of life depended for its continuation had been very greatly enlarged by the ecologically distinctive traits of modern humans. So the depletion of almost any one of many resources that were now essential could put the brakes on our neo-exuberance.
[...]
The Real Error
Malthus did indeed err, but not in the way that has been commonly supposed. He rightly discerned “the power of population” to increase exponentially “if unchecked.” He rightly noted that population growth ordinarily is not unchecked. He saw that it was worth inquiring into the means by which the exponential growth tendency is normally checked. He was perceptive in attaching the label “misery” to some of the ramifications of these means. Where he was wrong was in supposing that the means worked fully and immediately. (That this was his error has not been seen by those who reject his views.)
Being himself under the impression that it was not possible for the human load to exceed the earth’s carrying capacity, Malthus enabled those who came after him to go on misconstruing continued impressive growth as evidence against, rather than as-evidence for, his basic ideas. Carrying capacity was a concept almost clear to Malthus. He even sensed that the carrying capacities of earth’s regions had been repeatedly enlarged by human cultural progress.20 If he was not yet able to make clear to himself and his readers the distinction between means of enlarging carrying capacity and means of overshooting it, we do ourselves a serious disservice by perpetuating his shortcoming. And we do just such a disservice by continuing to mistake overshoot for progress, supposing drawdown to be no different from takeover. By erring thus we prolong and deepen our predicament.
Despite Malthus’s belief to the contrary, it is possible to exceed an environment’s carrying capacity—temporarily. Many species have done it. A species with as long an interval between generations as is characteristic of ours, and with cultural as well as biological appetites, can be expected to do it. Our largest per capita demands upon the world’s resources only begin to be asserted years after we are born. Resource depletion sufficient to thwart our children’s grown-up aspirations was not far enough advanced when our parents were begetting, gestating, and bearing us to deter them from thus adding to the human load.
By not quite seeing that carrying capacity can be temporarily overshot, Malthus understated life’s perils. He thus enabled both the admirers and the detractors of his admonitory writings to neglect the effects of overshoot—environmental degradation and carrying capacity reduction. In his analyses he assumed linear increase of carrying capacity. While this fell short of sustaining exponential growth of would-be consumers, it was, even so, a far brighter prospect than carrying capacity reduction.
Hubbert has issued a correction as of 03:32 on Sep 17, 2021
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