Overpopulation

Overpopulation occurs when the population of a living species exceeds the carrying capacity of its ecological niche. In common parlance, the term usually refers to the relationship between the human population and its environment (the planet Earth).

Overpopulation is not a function of the number or density of the individuals, but rather the number of individuals compared to the resources they need to survive. In other words, it is a ratio: population over resources. If a given environment has a population of 10, but there is food and drinking water enough for only 9 people, then that environment is overpopulated, while if the population is 100 individuals but there are food and water enough for 200, then it is not overpopulated, but it is underpopulated

Overpopulation can result from increases in births, a decline in mortality rates (an increases in life expectancy), or from an unsustainable use and depletion of resources. Advances in technology can reduce the threat of overpopulation by making new resources available, or by increasing the productivity of existing resources.

Resources to be taken into account when estimating if an ecological niche is overpopulated include clean water, food, shelter, warmth, etc. In the case of human beings, there are others such as arable land and, for all but tribes with primitive lifestyles, lesser resources such as jobs, money, education, fuel, electricity, medicine, proper sewage and garbage management, and transportation.

In the context of human societies, overpopulation occurs when the population density is so great as to actually cause an impaired quality of life, environmental degradation, or a long-term shortages of essential goods and services. Overpopulation is not merely an imbalance between the number of individuals compared to the resources they need to survive, or a ratio of population over resources. This is because such an imbalance may be caused by any other number of factors such as bad governance, war, injustice and exploitation, etc. When other such factors come into play in a certain locale, and population density cannot be shown to be the major cause, overpopulation cannot be conclusively said to occur.

The world's human population is currently growing by more than 75 million people per year. This is down from a peak numerical growth of about 88 million per year in the late 1980s. About half the world lives in nations with sub-replacement fertility, and population growth in those countries is due to immigration.

Contents 1 Malthus' theory 2 Population as a function of food availability 3 Population projections 4 The optimist's viewpoint on population growth 5 Effects of overpopulation 6 The demographic transition 7 The status of women 8 "Survival of the fittest" 9 Medicine shortages 10 Fossil-fuel subsidies in agriculture 11 US immigration policy 12 Overpopulation as a social issue 13 Overpopulation as a theme in fiction 14 Population projections in space 15 References 16 See also 17 External links

Malthus' theory

Thomas Malthus argued in An Essay on the Principle of Population, first published in 1798, that if left unrestricted, human populations would continue to grow until they would become too large to be supported by the food grown on available agricultural land. He proposed that, while resources tend to grow linearly, population grows exponentially. At that point, the population would be restrained through mass famine and starvation. Malthus argued for population control, through "moral restraint", to avoid this happening. As the population exceeds the amount of resources the population decreases, since the lack of resources causes mortality to increase. This process keeps the population in check and ensures it doesn't exceed the amount of resources.

Over the two hundred years which followed, famine has overtaken numerous individual regions; proponents of this theory state that these famines were examples of Malthusian catastrophes. On a global scale, however, food production has grown faster than population. It has often been argued that future pressures on food production, combined with threats to other aspects of the earth's habitat such as global warming, make overpopulation a still more serious threat in the future. Perhaps the best-known example of such an argument is The Limits to Growth, a report produced for the Club of Rome in the early 1970s. More recent examples also exist [1].

Population as a function of food availability

Recent studies attack the contemporary belief that human populations are a naturally explosive independent variable. Thinkers such as Professor David Pimentel (Cornell), Dr. Alan Thornhill, Russell Hopffenberg and author Daniel Quinn propose that like other animals, human populations predictably grow and shrink according to their available food supply – populations grow in an abundance of food, and shrink in times of scarcity.

Proponents of this theory indicate that every time food production is intensified to feed a growing population, the population responds by increasing even more. Some human populations throughout history support this theory, as consistent population growth began with the agricultural revolution, when food supply began consistantly increasing- and continues to do so today. This can be observed in cultural contexts, as populations of hunter-gatherers fluctuate in accordance with the amount of available food and are significantly smaller than populations of agriculturalists, who increase the amount of food avaible by putting more land under agriculture.

For some, the concept that human populations behave in the same way as do populations of bears and fish is troubling to believe; for others it indicates a feasible solution to population issues. In either case, since populations are made of the food they consume, it seems that discussion of populations should not take place without considering the role played by food supply.

Critics of this idea point out that birth rates are voluntarily the lowest in developed nations, which also have the highest access to food. In fact, the population is decreasing in some countries with abundant food supply. Thus human populations do not always grow to match the available food supply. Factors cited in the decline of birthrates include such social factors: increased access to contraception; later ages of marriage; the growing desire of many women in such settings to seek careers outside of childrearing and domestic work; and the decreased need of children in industrialized settings. The latter explanation stems from the fact that children perform a great deal of work in small-scale agricultural societies, and work less in industrial ones; it has been cited to explain the drop-off in birthrates worldwide in all industrializing regions.

Food production has outpaced population growth, meaning that there is now more food available per person than ever before in history. Studies project that food production can continue to increase until at least 2050. At the same time, world population is predicted to slow its growth, reaching 9.1 billion by 2050 in the median scenario. Net growth by mid century is predicted to be 34 million per year in contrast to the roughly 76 million per year that was seen from 2000 to 2005. [2] Another United Nations report projects that world population will peak at 9.2 billion in 2075 [3][4].

Population projections

Image:World population evolution.png According to projections by the Population Division of the United Nations revised in 2004 [5], the population of the world will stabilize at 9.1 billion by 2050 due to demographic transition. The UN has consistently revised its population projections downwards over the last 10 years. Birth rates are now falling in most developing countries, while the population in many developed countries would also fall without immigration [6].

David Pimentel, a professor of ecology and agricultural sciences at Cornell University, predicts that population outcomes for the 22nd century range from 2 billion people (characterised as thriving in harmony with the environment), to 12 billion people (characterised as miserable and suffering a difficult life with limited resources and widespread famine). [7]

The optimist's viewpoint on population growth

Other studies have countered with the claim that the current population level of over six billion may be supported by current resources, or that the global population may grow to ten billion and still be within the Earth's carrying capacity. In The Skeptical Environmentalist, published in 2001, Bjørn Lomborg argued that because of the falling rate of population growth, and because of new, alternative technologies, there is no problem with overpopulation. The assumptions that underlie these claims, however, have been strongly criticised. One criticism is that poor people can't afford such technologies. However, it is also possible the Earth is capable of sustaining more humans without the need for such technology.

In any case, many proponents of population control have averred that famine is far from being the only problem attendant to overpopulation. These critics point out ultimate shortages of energy sources and other natural resources, as well as the importance of serious communicable diseases in dense populations, and war over scarce resources such as land area.

A shortage of arable land (where food crops will grow) is a problem. About 21% of the earth's land is arable. In the past, 160 acres (650,000 m²) of farm land crops fed one person. Hydroponics in autonomous building gardens and greenhouses grow more food in less space. Most food production experiments have used vegetable farming because it can support an adult from as little as 15 m² of land. High crop yield vegetables like potatoes and lettuce do not waste space with inedible plant parts, like stalks, husks, vines, and inedible leaves. New varieties of selectively bred and hybrid plants have larger edible parts (fruit, vegetable, grain) and smaller inedible parts. With new technologies, it is now possible to grow crops on some unarable land under certain conditions. Aquaculture could theoretically dramatically increase available area. Hydroponics and food from bacteria and fungi, like Quorn, may allow the growing of food without having to consider land quality, climate, or even available sunlight.

It is hoped that technologies and methods which follow the concepts of sustainability will allow better lives for more people. This viewpoint is typically named Cornucopian.

Effects of overpopulation

The world's current agricultural production, if it were distributed evenly, would be sufficient to feed everyone living on the Earth today. However, many critics hold that, in the absence of other measures, simply feeding the world's population well would only make matters worse, natural growth will cause the population to grow to unsustainable levels, and will directly result in famines and deforestation and indirectly in pandemic disease and war.

Some other characteristics of overpopulation:

• People struggling to live under poor conditions
• Birth rate is low due mothers are unable to get enough resources to sustain a baby from fertilization to birth
• Life expectancy is low
• Low level of literacy
• High rate of unemployment in urban areas (leading to social problems)
• Insufficient arable land
• Little surplus food
• Poor diet with ill health and diet-deficiency diseases (e.g. rickets)
• GDP per capita is low, however financial focus be lessen due people will be more interested in resources than financial need
• Many live in unhygienic conditions
• Government is stretched economically
• High crime from people who steal resources to survive
• Mass extinctions of plants and animals as habitat is used for farming and human settlements
• Human population that continues to decrease until a right balance is achieved

The demographic transition

However, others contend that within a generation after the standard of living and life expectancy starts increasing, family sizes start dropping in what is termed the demographic transition. In support they point to the contention that every estimate of maximum global population since the 1960s, when the "population explosion" became a worry, has been significantly lower than the previous estimates. Among those holding this view are the ecologist Paul Colinvaux, who writes on the topic in Why Big Fierce Animals are Rare, and The Fates of Nations.

Today about half the world lives in nations with sub-replacement fertility. All the nations of East Asia, with the exceptions of Mongolia, the Philippines, and Laos are below this level. Russia and Eastern Europe are in most cases quite dramatically below replacement fertility. Western Europe also is below replacement. In the Middle East Iran, Tunisia, Algeria, Turkey, and Lebanon are below replacement. Canada, Australia, and New Zealand are similar to Western Europe, while the United States is just barely below replacement with about 2.0 births per woman. All four of these nations still have growing populations due to high rates of immigration. The countries having the lowest fertility are Hong Kong, Macao, Singapore and Lithuania.

The status of women

Another point of view on population vs. the standard of living is that of Virginia Abernethy in Population Politics, in which she shows her evidence that this effect only holds true in nations where she claims women enjoy a special status. In strongly patriarchal nations, where she claims women enjoy few special rights, a high standard of living tends to result in population growth. She argues that foreign aid to poor countries must include significant components designed to improve the education, human rights, political rights, political power, and economic and sexual status and power of women.

"Survival of the fittest"

Some approach overpopulation with a "survival of the fittest," "laissez-faire" attitude, arguing that if the Earth's ecosystem becomes overtaxed, it will naturally regulate itself. In this mode of thought, disease or starvation are natural means of lessening population. Two particular objections to this argument are that a) in the meantime, a huge number of plant and animal species become extinct (a thing that already happened long before humans existed), and b) this would result in terrible pollution in some areas that would be difficult to abate however the damages will not be too suffered.

Others argue that economic development is the best way to reduce population growth. Many developed countries in the world today, such as Italy, now have declining populations (ignoring the effects of immigration).

In either case, it is often held that the most productive approach is to provide a combination of help targeted towards population control and self-sufficiency. One of the most important measures proposed for this effort is the empowerment of women educationally, economically, politically, and in the family. Which would lead to more fertile mothers. The value of this philosophy has been substantially borne out in cases where great strides have been taken to this goal: where women's status has dramatically improved, there has generally been a drastic reduction in the birthrate to more sustainable levels. Other measures include effective family planning programs, local renewable energy systems, sustainable agriculture methods and supplies, reforestation, and measures to protect the local environment.

Medicine shortages

The largest shortage for important resources is of medicine. A shortage of educated people can lead to a shortage of doctors. Fewer doctors in a population causes the price of medical services to rise. This can either cause a government subsidised healthcare system to be unsustainable or lead to increased medical bills and health insurance costs to rise.

Fossil-fuel subsidies in agriculture

One of the strongest criticisms of an optimistic outlook is that of the fossil fuel subsidy of modern agriculture. The extremely high agricultural outputs of modern farms depend entirely on immense fossil fuel (mostly petroleum) subsidies in the forms of fertilizers, equipment fuel, and other chemicals such as pesticides. There is much discussion regarding a future peak in oil production and its consequences. See Hubbert peak and Future energy development. However, most of the worlds population uses some to no fossil fuels at all.

US immigration policy

Some overpopulation activists have taken the position that population growth must be dealt with on a country-by-country basis, and therefore support a reduction in immigration into some countries, including the United States, in order to stabilize their population. Others disagree with this approach and believe that population should be addressed only as a global issue, not through immigration restrictions. Regardless of differing views on immigration policy, most population activists agree on the need for birth control, family planning, and the empowerment of women. Among the groups who take a position in support of immigration reductions is Negative Population Growth; among those who do not take a position on immigration and concentrate instead on birth control and family planning is Population Connection, formerly Zero Population Growth. This debate has also been ongoing in some parts of the broader environmental movement, especially Earth First! during the 1980s, and more recently has become an especially contentious issue within the Sierra Club.

Overpopulation as a social issue

The density of population has an impact on a broad range of social and economic issues, such as land prices and housing costs. For example, relatively densely populated countries such as Japan have higher land prices than less densely populated countries such as Australia, and even in that country, land prices have doubled and redoubled as the population has increased. It is sometimes argued that reducing the populations of some areas, such as large cities, would have positive benefits for these reasons.

Overpopulation as a theme in fiction

Science fiction writers have frequently made famous predictions in which they portrayed dystopian futures in which the world has become massively overpopulated. This became a major theme in the 1950s and 1960s. One of the first depictions of future megacities was The Caves of Steel by Isaac Asimov (1954). The 1960s saw increasing anxiety about the prospect of the exponential growth of world population, underscored by the publication of Paul R. Ehrlich's non-fiction The Population Bomb, in 1968.

In the same year, John Brunner's science-fictional Stand on Zanzibar was published. This is perhaps the definitive overpopulation novel to date, though others such as Harry Harrison's Make Room! Make Room! also became a powerful movie (Soylent Green). Logan's Run is a novel by William F. Nolan and George Clayton Johnson (1967), describing a dystopian future society in which the population is kept young by euthanizing everyone who reaches a certain age, thus neatly avoiding the problem of overpopulation. A 1972 film called Z.P.G. featured an overpopulated, very polluted future Earth, whose world government practices Zero Population Growth, executing persons who violate the 30-year ban on procreation.

J. G. Ballard's story "Billennium" pictures a future in which every individual has four, then just three, square metres of living space. Frederick Pohl in "The Space Merchants" described a future in which even public staircases are rented out as living spaces. Robert Silverberg's The World Inside imagines a future with mile high towers holding a million people each. James Blish and Norman L. Knight in A Torrent of Faces imagine a nightmarish future of 1,000 billion living in just 100,000 cities on Earth.

From the 1980s, there has been an evident lessening of such fears in science fiction. Cyberpunk fiction, such as that of William Gibson, often depicts huge, sprawling cities. Yet these are as remarkable for their energy and diversity as for their more dystopian characteristics.

Population projections in space

Many authors (eg. Carl Sagan, Arthur C. Clarke, Isaac Asimov) have pointed out the obvious absurdity of "solving" overpopulation through shipping the excess population into space, arguing that (Clarke, 1999) "the population battle must be fought or won here on Earth".

Space advocists and others have nonetheless made various projections regarding future human population growth in space.

Even as far back as 1798, Thomas Malthus stated in An Essay on the Principle of Population:

"The germs of existence contained in this spot of earth, with ample food, and ample room to expand in, would fill millions of worlds in the course of a few thousand years."

Gerard O'Neill has suggested that, taking the completion of his proposed Island One as year zero, maximum population growth could then result in a population of 7.3 billion within 35 years.

Marshall Savage (1992, 1994) has projected a population of five billion billion throughout the solar system by 3000, with the majority in the asteroid belt. Clarke, a fervant supporter of Savage, now argues that by 2057 there will be humans on the Moon, Mars, Europa, Ganymede, Titan and in orbit around Venus, Neptune and Pluto.

Anthony Burgess, in his novel "The Wanting Seed" speculated that in the future homosexuality will be considered normal and that the dead will be drained of minerals due to the poor condition of the Earth.

Freeman Dyson (1999) favours the Kuiper belt as the future home of humanity, suggesting this could happen within a few centuries.

K. Eric Drexler, famous inventor of the futuristic concept of Molecular Nanothechnology, has suggested in Engines of Creation that colonising space will mean breaking the Malthusian limits to growth forever for the human species.

Considered to be the most mind boggling prediction is that of John S. Lewis in Mining the Sky. Bordering on the overpopulation of the solar system itself, Lewis suggests that the staggering resources of the solar system could support 10,000,000 billion people.

References

• The Science in Science Fiction, (1982) - editor Peter Nichols. Roxby Science Fiction Ltd. ISBN 0-7181-2187-2
• Close Encounters? Science and Science Fiction (1990) - Robert Lambourne, Michael Shallis, Michael Shortland. IOP publishing - Adam Hilger. ISBN 0-85274-141-3
• Marshall Savage, (1992, 1994) The Millennial Project: Colonizing the Galaxy in Eight Easy Steps. Little, Brown. ISBN 0-316-77163-5
• The Sun, The Genome, and The Internet, (1999) - Freeman Dyson. Oxford University Press. ISBN 0-19-513922-4
• The Good Earth Is Dying, (1971) - Isaac Asimov. (published in Der Spiegel).
• Greetings, Carbon-Based Bipeds! (1999) - Arthur C. Clarke. Voyager. ISBN 0-00-224698-8
• Mining the Sky (1996) - John S. Lewis. Addison Wesley. ISBN 0-201-47959-1
• The High Frontier (1976, 2000) - Gerard O'Neill. Apogee Books. ISBN 1-896522-67-X

See also

• Albert Bartlett
• Paul R. Ehrlich
• Julian Lincoln Simon
• Population control
• Population density
• Sub-replacement fertility
• Underpopulation
• Urban sprawl
• Immigration reduction
• Tragedy of the commons
• National Security Study Memorandum 200
• Over-consumption

External links

• A Crusade Against Overpopulation
• Planned Parenthood mission and population stance
• Ecofuture.org Population and Sustainability Website
• Global issues that affect everyone
• Map over population density
• Negative Population Growth (organization)
• Population Action International (organization)
• Population Connection (formerly Zero Population Growth; organization)
• Population-Environment Balance (organization)
• Overpopulation.com (skeptical site)
• Sierra Club's Population Campaign (organization)
• SUSPS (concerned with the Sierra Club's immigration policy; organization)
• Humanity has no enemies apart from itself (English and Lithuanian)
• World population projections by the United Nations "World Population to 2300"
• Stop Terrible Human OverPopulation Disasters (eCards website to save nature)
• WiseArt Cybernetics (On-line slideshow to limit human overpopulation)
• World Population Balance (organization)
• Is World Population a Concern? Robert Heilbroner, Thomas Malthus, and the Application of Both
• Overpopulation and Happiness
• DieOff.org, seminal human population crash website
• Appeal to Marco Pannella on overpopulation
• Sustainable Population Australiada:Overbefolkning

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