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MALTHUSIAN CATASTROPHE
A Malthusian catastrophe, sometimes known as a Malthusian check, Malthusian crisis, Malthusian dilemma, Malthusian disaster or Malthusian trap, is a return to subsistence-level conditions as a result of agricultural (or, in later formulations, economic) production being eventually outstripped by growth in population. Theories of Malthusian catastrophe are very similar to the subsistence theory of wages. The main difference is that the Malthusian theories predict over several generations or centuries whereas the subsistence theory of wages predicts over years and decades.
Traditional views
In 1798 Thomas Malthus published An Essay on the Principle of Population, describing his theory of quantitative development of human populations:
- I think I may fairly make two postulata. First, That food is necessary to the existence of man. Secondly, That the passion between the sexes is necessary and will remain nearly in its present state. These two laws, ever since we have had any knowledge of mankind, appear to have been fixed laws of our nature, and, as we have not hitherto seen any alteration in them, we have no right to conclude that they will ever cease to be what they now are, without an immediate act of power in that Being who first arranged the system of the universe, and for the advantage of his creatures, still executes, according to fixed laws, all its various operations.
- [...]
- Assuming then my postulata as granted, I say, that the power of population is indefinitely greater than the power in the earth to produce subsistence for man. Population, when unchecked, increases in a geometrical ratio. (Malthus 1798, Chapter 1, online [1])
Series increasing in geometric progression are defined by the fact that the quotient of any two successive members of the sequence is a constant (e.g. a populations has an average birth rate of, say 1.2, or in the Malthusian' world of the 18th century, maybe rather 2.3 babies per population member in 50 years: so the entire unchecked population will grow in a ratio of 1.2 or 2.3 per 50 years). Malthus assumed the growth of agrarian economics to be linear (the arithmetic ratio is defined so that any two successive members of the sequence have a constant difference).
If unchecked, progressive growth can easily outrun linear growth, even if the quotient between successive sequence members is only slightly larger than 1.0. So Malthus concluded that the population will be naturally checked by misery, vice or the like in natural development. Every phase of unchecked exponential progression (possible e.g. when inhabiting new habitats or colonies, e.g. on the American continent at Malthus' time, or when recovering from wars and epidemic plagues) will be followed by a catastrophe or misery, and thus unlimited growth may even directly cause misery and vice (Malthus 1798, chapter 7: "A probable cause of epidemics", online [2]).
Neo-Malthusian theory
Neo-Malthusian theory argues that unless at or below subsistence level, a population's fertility will tend to move upwards. Assume for example that a country has 10 breeding groups. Over time this country's fertility will approach that of its fastest growing group in the same way that
will eventually come to resemble
regardless of how large the constant a is or how small the constant b is. Under subsistence conditions the fastest growing group is likely to be that group progressing most rapidly in agricultural technology. However, in above-subsistence conditions the fastest growing group is likely to be the one with the highest fertility. Therefore the fertility of the country will approach that of its most fertile group. This, however, is only part of the problem.
In any group some individuals will be more pro-fertility in their beliefs and practices than others. According to neo-Malthusian theory, these pro-fertility individuals will not only have more children, but also pass their pro-fertility on to their children, meaning a constant selection for pro-fertility similar to the constant evolutionary selection for fertility genes (except much faster because of greater diversity). According to neo-Malthusians, this increase in fertility will lead to hyperexponential population growth that will eventually outstrip growth in economic production. This appears to make any sort of voluntary fertility control futile, in the long run. Neo-Malthusians argue that although adult immigrants (who, at the very least, arrive with human capital) contribute to economic production, there is little or no increase in economic production from increased natural growth and fertility. Neo-Malthusians argue that hyperexponential population growth has begun or will begin soon in developed countries.
To this can be added that, unknown to Malthus, farmland deteriorates with use. Some areas where there was intensive agriculture in classic times had already declined in population because their farmland was worn out, long before he wrote.
Is the catastrophe occurring?
At the time Malthus wrote, most societies had populations at or near their agricultural limits. But by the 1970s, agricultural technologies of the green revolution had expanded agricultural production in some parts of the world (exponential not arithmetic growth rate as Malthus believed, for food production), and what he termed 'misery': premature deaths, war, political unrest, and other forms of population control would lower population far before the famine he believed would occur.
Numerous scholars accept that Malthus' catastrophe is occurring, but not necessarily in a spectacular way that commands daily headlines. In particular Pimentel and Nielsen (using independent analyses) find that the human population has passed the numerical point where all can live in comfort, and that we have entered a stage where many of the world's citizens and future generations are trapped in misery[3]. There is evidence that a catastrophe is underway as of at least the 1990s; for example, by the year 2000, children in developing countries were dying at the rate of approximately 11,000,000 per annum from strictly preventable diseases[1][2]. This data suggests that by the standard of misery, the catastrophe is underway.
Regarding famines, there is abundant data demonstrating the world's food production has peaked in the very regions where food is needed the most. For example in South Asia, approximately half of the land has been degraded such that it no longer has the capacity for food production[3]. In China there has been a 27 percent irreversible loss of land for agriculture, and continues to lose arable land at the rate of 250,000 hectares per year[4]. In Madagascar, at least 30 percent of the land previously regarded as arable is irreversibly barren.
Many technologically developed countries have by 2006 passed through the demographic transition, a complex social development in which total fertility rates drop in response to lower infant mortality, more education of women, increased urbanization, and a wider availability of effective birth control. By the end of the 20th century, these countries could avoid population declines by permitting large-scale immigration. On the untested assumption that the demographic transition would spread to less developed countries, the United Nations Population Fund estimated that human population would peak in the late 21st century rather than continue to grow until it exhausted available resources. There is considerable doubt about the validity of the UN projections, since they are below all of the projections by others which have a more scientific standing[5]. The most important point is that none of the estimates (including those of the UN, as opposed to their publications which often misquote their own projections) assume the population growth to level in 2050. Some other estimates indicate population growth will not even slow until a value above 16 billion is reached.
The actual growth curve of the human population is another issue. In the latter part of the 20th century many argued that it followed exponential growth; however, a more common view starting in 2000 is that the growth in the last millennium has been faster, termed hyperbolic or hyperexponential. An exponential portion of the human population growth curve is actually the lower limb of a logistic curve, or a section of a Lotka-Volterra cycle. Also, examination of records of estimated total world human population ([4] [5]) shows deviation from exponential; some of these deviations are hyper-exponential (or faster than simple exponential) and for some western countries populations are falling. The official UN projections are at the low end of all the reliable population projections, and some analysts consider the UN estimates politically driven.
A chart of estimated world population 1800-2050. Only the section in blue is made of reliable counts, and not estimates.
The graph of percentage annual increase also does not appear as one would expect for exponential growth. For exponential growth it should be a straight line at constant height, whereas in fact it had a big surge in the mid-1960s (presumably attributable to the Green revolution) and has been generally trending downward ever since.
Though short-term trends, even on the scale of decades or centuries, do not disprove the underlying mechanisms promoting a Malthusian catastrophe over longer periods, the prosperity of a small fraction of the human population at the beginning of the 21st century, and the debatability of ecological collapse made by Paul R. Ehrlich in the 1960s and 1970s, has led some people, such as economist Julian L. Simon, to question its inevitability.
Application to energy/resource consumption
Another way of applying the Malthusian theory is to substitute other resources, such as sources of energy for food, and energy consumption for population. (Since modern food production is energy and resource intensive, this is not a big jump. Most of the criteria for applying the theory are still satisfied.) Since energy consumption is increasing much faster than population and most energy comes from polluting and non-renewable sources, the catastrophe appears more imminent, though perhaps not as certain, than when considering food and population continue to behave in a manner contradicting Malthus's assumptions.
Retired physics professor Albert Bartlett, a modern-day Malthusian, has lectured on "Arithmetic, Population and Energy" over 1,500 times. He published an article entitled Thoughts on Long-Term Energy Supplies: Scientists and the Silent Lie in Physics Today (July 2004). For a response to Bartlett's argument, see two articles on energy and population in Physics Today, November 2004 [6], and following letters to the editor.
A further way of analyzing resource limitation is the dwindling area for storage of soil contaminants and water pollution. The high rate of increase in toxic chemicals in the environment (especially persistent organic chemicals and endocrine altering chemicals) is creating a circumstance of resource limitation (e.g. safe potable water and safe arable land).
See also
References
- ^ U.S. National Research Council, Commission on the Science of Climate Change, Washington D.C. (2001)
- ^ Ron Nielsen, The Little Green Handbook, Picador, New York (2006) ISBN 3-312-42581-3
- ^ Ron Nielsen, The Little Green Handbook, pg. 52, Picador Press, New York (2006) ISBN 3-312-42581-3
- ^ UNEP, Global Environmental Outlook 2000, Earthscan Publications, London, UK (1999)
- ^ Ron Nielsen, The Little Green Handbook, pp. 18-25, Picador Press, New York (2006) ISBN 3-312-42581-3
External links
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