Overpopulation
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226186621
2008-07-17T06:13:17Z
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Removed stupid comment by some vandal.
{{POV|date=December 2007}}
[[Image:World population density map.PNG|right|thumb|350px|Map of [[countries]] by [[population density]] (See ''[[List of countries by population density]].'')]]
[[Image:Population density.png|right|thumb|350px|Areas of high population densities, calculated in 1994.]]
[[Image:Fertility rate world map 2.png|thumb|350px|Map of countries and territories by [[Total fertility rate|fertility rate]] (See ''[[List of countries and territories by fertility rate]].'')]]
'''Overpopulation''' refers to a condition where an [[organism]]'s numbers exceed the [[carrying capacity]] of its [[habitat]]. In common parlance, the term usually refers to the relationship between the [[world population|human population]] and its [[Natural environment|environment]], the [[earth]].<ref>[http://www.guardian.co.uk/environment/2007/aug/31/climatechange.food Global food crisis looms as climate change and population growth strip fertile land]</ref>
Overpopulation is not solely a function of the size or density of the population. Overpopulation can be determined using the ratio of population to available sustainable resources. If a given environment has a population of ten, but there is food or drinking water enough for only nine, then that environment is overpopulated; if the population is 100 individuals but there is enough food, shelter, and water for 200 for the indefinite future, then it is not. Overpopulation can result from an increase in [[List of countries and territories by fertility rate|births]], a decline in [[mortality rate]]s due to [[History of medicine#Modern medicine|medical advances]], from an increase in [[immigration]], a decrease in [[emigration]], or from an [[Sustainability|unsustainable]] [[biome]] and depletion of resources. It is possible for very sparsely-populated areas to be overpopulated, as the area in question may have a very meager or non-existent capability to sustain human life (e.g. the middle of the [[Sahara]] desert or Antarctica).
The resources to be considered when evaluating whether an [[ecology|ecological]] niche is overpopulated include [[drinking water|clean water]], clean air, food, shelter, warmth, and other resources necessary to sustain life. If the quality of human life is addressed as well, there are then additional resources to be considered, such as medical care, employment, money, education, fuel, electricity, proper sewage treatment, [[waste]].
Some countries have managed to increase their [[carrying capacity]] by using technologies such as [[agriculture]] and [[desalination]]. Some have argued that poverty and famine are caused by bad government and bad economic policies, and that higher population density leads to more [[specialization]] and [[technological innovation]], and that this leads to a higher standard of living.<ref>[http://www.juliansimon.com/writings/Ultimate_Resource/ The Ultimate Resource 2] Julian Simon</ref><ref>[http://www.jewishworldreview.com/cols/williams022499.asp Population control nonsense] Walter Williams, Feb. 24, 1999</ref><ref>[http://jewishworldreview.com/jeff/jacoby051407.php3 A world of good news]Jeff Jacoby, May 14, 2007</ref><ref>[http://www.pregnantpause.org/overpop/gnp.htm Overpopulation and Standard of Living]</ref><ref>[http://www.jewishworldreview.com/cols/sowell021298.html%22 Thomas Sowell Julian Simon, combatant in a 200-year war]Thomas Sowell, February 12, 1998</ref><ref>[http://www.overpopulation.com/faq/ Overpopulation.Com FAQ]</ref><ref>[http://www.catholiceducation.org/articles/population/pc0001.html Too Many People?] JACQUELINE R. KASUN</ref> Others argue that overpopulation is an important cause of these problems.<ref name="Nielsen">Ron Nielsen, ''The Little Green Handbook: Seven Trends Shaping the Future of Our Planet'', Picador, New York (2006) ISBN 978-0312425814</ref><ref>E.O. Wilson, ''The Future of Life''</ref><ref>[http://www.pregnantpause.org/overpop/gnp.htm Overpopulation and Standard of Living<!-- Bot generated title -->]</ref><ref>[http://jewishworldreview.com/jeff/jacoby051407.php3 Jeff Jacoby<!-- Bot generated title -->]</ref>
==Overpopulation predictions==
In ''[[An Essay on the Principle of Population]]'' (first published in 1798), [[Thomas Malthus]] proposed that while resources tend to grow linearly, population [[exponential growth|grows exponentially]]. He argued that, if left unrestricted, human populations continue to grow until they become too large to be supported by the food grown on available agricultural land, causing starvation which then controls population growth. He noted that this had happened many times previously in human history and estimated that this would occur again by the middle of the 19th century. To avoid this outcome, Malthus argued for [[population control]] through "moral restraint." He correctly predicted that population growth could decline or reverse with later marriages and "vices" like contraception (see for example, the [[demographic transition]]). The warnings and predictions of Malthus are commonly referred to as the [[Malthusian catastrophe]].
On a global scale, since the industrial revolution, food production has sometimes grown faster than human population. However, it has been argued that other changes impacting Earth's ability to function as a suitable habitat for human beings, such as [[global warming]], [[desertification]], [[overfishing]], [[peak oil]], [[soil degradation]], [[deforestation]], [[aquifer|aquifer depletion]] and other environmental problems caused by industrialization, will significantly reduce food production or factors necessary for well-being. Given recent population growth, this may cause a Malthusian catastrophe.
Among the earlier best-known modern examples of such arguments are ''[[Limits to Growth|The Limits to Growth]]'' (1972) and ''[[The Population Bomb]]'' (1968) by [[Paul R. Ehrlich]].
Paul Ehrlich predicted, "the population of the U.S. will shrink from 250 million to about 22.5 million before 1999 because of famine and global warming", though it should be noted that between 1950 and 1984, as the [[Green Revolution]] transformed [[agriculture]] around the globe, world grain production increased by 250%,<ref>[http://www.fromthewilderness.com/free/ww3/100303_eating_oil.html Eating Fossil Fuels<!-- Bot generated title -->]</ref> and the source of his quote, a 1969 short story called "Eco-catastrophe" reprinted from "Ramparts" Magazine, was apparently a work of science fiction.<ref>[http://www.bestsf.net/reviews/harrisonaldiss1969.html Best SF : 1969<!-- Bot generated title -->]</ref> Ehrlich also predicted, "Before 1985, mankind will enter a genuine age of scarcity . . . in which the accessible supplies of many key minerals will be facing depletion." According to [[The Skeptical Environmentalist]] by [[Bjørn Lomborg]], Ehrlich's predictions did not materialise.<ref>[http://www.washingtonpost.com/ac2/wp-dyn/A12789-2001Oct18?language=printer washingtonpost.com: Greener Than You Think<!-- Bot generated title -->]</ref>
(See [[The Population Bomb#Ehrlich answers critics|Erlich's answer to his critics]] and [[The Ultimate Resource]], by [[Julian Simon]], which challenges Ehrlich's ideas.) Simon himself once stated "We now have in our hands in our libraries, really the technology to feed, clothe, and supply energy to an ever-growing population for the next 7 billion years... We [are] able to go on increasing forever" (Myers and Simon, 1994, 65). These comments have subjected Simon himself to criticism.<ref>[http://info-pollution.com/simon.htm Correcting myths from Julian Simon<!-- Bot generated title -->]</ref>
In [http://www.alternet.org/story/18978/ Facing the Limits to Growth] the authors of the 1972 study ''[[Limits to Growth]]'' tell of the difficulty in getting the idea of the necessity of limiting human population growth past "Entrenched political, economic, and religious cliques." And they acknowledge that revision has been necessary, "Because of the long time horizon involved in our studies, we always realized it would require several decades to get any perspective on the accuracy of our forecasts", however, "the basic conclusions are still the same. We have modified our model only a little to reflect some better data about the effects of technology on land yields and birth rates."<ref>{{cite web
|url=http://www.chelseagreen.com/2004/items/limitspaper
|title=Limits to Growth: The 30-Year Update
|publisher=Chelsea Green Publishing
}}</ref>
Between 1950 and 1984, as the [[Green Revolution]] transformed agriculture around the globe, world grain production increased by 250%. However, agricultural productivity has declined in many world regions in the past ten to 20 years due to [[overdrafting]] of [[groundwater]] (such as has occurred on the North Plain of China) , [[overgrazing]], extensive [[slash-and-burn]] and resulting soil exhaustion and erosion. The energy for the Green Revolution was provided by fossil fuels in the form of [[fertilizers]] (natural gas), [[pesticides]] (oil), and [[hydrocarbon]] fueled [[irrigation]].<ref>[http://wolf.readinglitho.co.uk/mainpages/agriculture.html How peak oil could lead to starvation]</ref> David Pimentel, professor of ecology and [[agriculture]] at [[Cornell University]], and Mario Giampietro, senior researcher at the National Research Institute on Food and Nutrition (INRAN), place in their study ''Food, Land, Population and the U.S. Economy'' the maximum [[U.S. population]] for a [[sustainability|sustainable economy]] at 200 million. To achieve a sustainable economy and avert [[disaster]], the [[United States]] must reduce its population by at least one-third, and [[world population]] will have to be reduced by two-thirds, says the study. The authors of this study believe that the mentioned agricultural crisis will only begin to impact us after 2020, and will not become critical until 2050.<ref>[http://www.energybulletin.net/281.html Eating Fossil Fuels | EnergyBulletin.net]</ref>
David Pimentel claims 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 difficult lives with limited resources and widespread famine).<ref>[http://www.utne.com/web_special/web_specials_archives/articles/799-1.html Ecologist Says Unchecked Population Growth Could Bring Misery<!-- Bot generated title -->]</ref>
The oncoming [[Hubbert peak theory|peaking of global oil]] production (and subsequent decline of production), along with the peak of North American [[natural gas]] production may precipitate this agricultural crisis much sooner than expected. Geologist [[Dale Allen Pfeiffer]] claims that coming decades could see spiraling [[food]] prices without relief and massive [[starvation]] on a global level such as never experienced before.<ref>[http://www.soilassociation.org/peakoil Peak Oil: the threat to our food security]</ref><ref>[http://europe.theoildrum.com/node/2225 Agriculture Meets Peak Oil]</ref><ref>[http://www.finfacts.com/irelandbusinessnews/publish/article_1011078.shtml Record rise in wheat price prompts UN official to warn that surge in food prices may trigger social unrest in developing countries]</ref>
The book ''The Little Green Handbook'' reasons that in 2050 about 7.7 billion people would be expected to suffer from illness, lack of adequate sanitation, hunger, and extreme poverty,<ref name="Nielsen">Ron Nielsen, ''The Little Green Handbook: Seven Trends Shaping the Future of Our Planet'', Picador, New York (2006) ISBN 978-0312425814</ref> provided that the high population estimates of year 2050 are realised.
In his recent book ''[[Collapse (book)|Collapse]]'' (2005), [[Jared Diamond]] argues that many earlier civilizations have collapsed due to environmental problems, and warns of current environmental problems. For example, he argues that it was overpopulation that led the now recovering inhabitants of [[Easter Island]] (a.k.a. Rapa Nui) to destroy their once beautiful island paradise.
{{cquote|From circa AD 1000 to circa 1650/1700 AD, [[Rapa Nui]]'s population increased significantly. Some estimate the population reached a high of 10,000 or even 15,000. [[Moai]] carving and transport were in full swing from 1400 to 1650, less than 100 years before the first recorded European visitors to the island. By the late nineteenth century the population had fallen to a low of 132. Deforestation, civil wars, European diseases and slave raiding all contributed to the population crash. Core sampling and archaeology from the island has revealed a slice of Rapa Nui history that speaks of [[deforestation]], extinction of native bird populations, soil depletion, and erosion as well as loss of access to deep sea fish as wood became scarce. From this devastating ecological scenario it is not hard to imagine the resulting overpopulation, food shortages, and [[societal collapse|ultimate collapse of Rapa Nui society]]. Evidence of [[cannibalism]] at that time is present on the [[island]], though very scant. Van Tilburg cautiously asserts, "The [[archaeological]] evidence for cannibalism is present on a few sites."<ref>[http://www.pbs.org/wgbh/nova/easter/civilization/first.html NOVA Online | Secrets of Easter Island | First Inhabitants<!-- Bot generated title -->]</ref>}}
However, he also notes situations in which humans have managed their natural resources well.
For reasons that are still debated, the [[Maya civilization|Maya]] centers of the southern lowlands went into decline during the [[8th century|8th]] and [[9th century|9th centuries]] and were abandoned shortly thereafter.<ref name="coe">{{cite book| last=Coe| first=Michael D.| title=The Maya| edition=6th| publisher=Thames & Hudson| year=2002| pages=pp. 151-155
|location=New York
|id=ISBN 0-500-28066-5}}</ref> There is evidence that the Maya population exceeded [[carrying capacity]] of the environment including exhaustion of [[agricultural]] potential and overhunting of [[megafauna]].<ref>[http://news.ufl.edu/2007/11/08/mayan-game/ University of Florida study: Maya politics likely played role in ancient large-game decline, Nov. 2007]</ref>
===Optimistic views on population===
In ''[[The Skeptical Environmentalist]]'', [[Bjørn Lomborg]] argues that, because of the falling rate of population growth in some parts of the world and because of new science and technologies, there is little problem with overpopulation. Several rebuttals<ref>M. Wackernagel, C. Manfreda and D. Deumling, ''Ecological Footprint of Nations'', November 2002 Update: How Much Nature do they Use? How Much Nature do they Have?'', Redefining Progress, San Francisco, Ca. (2002)</ref> of these arguments have in turn been responded to by Lomborg.<ref>http://www.lomborg.com/critique.htm</ref>
[[Julian Simon]] argued that any poor country that chose to adopt property rights would become wealthy, enabling science, technology, industrialization, modern agriculture, [[hydroponic farming]], nuclear power, and desalination, thereby enabling a rich, first world standard of living, even if the Earth had tens of billions of people.<ref name = "juliansimon-ultimate">[http://www.juliansimon.com/writings/Ultimate_Resource/ The Ultimate Resource II: People, Materials, and Environment<!-- Bot generated title -->]</ref>
In his 2007 book ''[[The Improving State of the World]]'', [[Indur M. Goklany]] argues that there is little problem with overpopulation, as humanity's state is rapidly improving overall and environmental problems can be overcome. He proposes that in the early stages of economic and technological development, negative environmental impacts increase because securing access to such necessities as food, shelter, and energy is seen as more important than protecting the environment. As development continues and these supply problems are solved, environmental impact becomes a higher priority, and steps are then taken to reduce it. This pattern can be seen for many environmental indicators, such as air quality, availability of safe water, sanitation, and toxic residues (e.g., [[DDT]] and [[Polychlorinated biphenyl|PCBs]]) in human tissues, which initially declined with increasing development but have more recently improved.
[[James Surowiecki]] argues in his [http://www.foreignaffairs.org/20070701fareviewessay86410/james-surowiecki/better-and-better-the-myth-of-inevitable-progress.html review] of the book that "The reality ... is that the fight over environmental regulation, at least in the United States, was -- and remains -- a fierce one and that environmental skeptics and businesses have done their best to prevent regulations such as the Clean Air and Clean Water Acts from ever becoming law. It is also the case that without those regulations, the 'cleaner planet' Goklany sees today would not exist.... The point is that far from being the inevitable product of a strong economy, environmental improvement is often the result of political struggles that could very easily have gone the other way." Goklansy in a reply stated "I am no more convinced than he is about the inevitability of progress" and that the book had stated "a democratic society, because it has the political means to do so, will translate its desire for a cleaner environment into laws, either because cleanup is not voluntary or rapid enough, or because of sheer symbolism. The wealthier such a society, the more affordable -- and more demanding -- its laws."[http://www.foreignaffairs.org/20071101faletter86674/indur-m-goklany/better-lives.html]
== Population growth ==
===The demographic transition===
[[Image:World population (UN).svg|thumb|right|300px|United Nation's population projections by location.]]
{{main|Demographic transition}}
The theory of demographic transition, while unproven to apply to all world regions, holds that widespread empirical evidence shows that after the standard of living and life expectancy increases, family sizes start dropping. Factors cited in the decline of birth rates include such social factors as later ages of [[marriage]], the growing desire of many women in such settings to seek [[career]]s outside of child rearing and domestic work, and the decreased need of children in [[industrialization|industrialized]] settings. The latter factor stems from the fact that [[children]] [[child labor|perform a great deal of work]] in small-scale agricultural societies, and work less in industrial ones; it has been cited to explain the dropoff in birth rates worldwide in all industrializing regions.
Another version of demographic transition is that of [[Virginia Abernethy]] in ''Population Politics'', in which she claims that the demographic transition is primarily in effect for nations where women enjoy a special status (''see'' [[Virginia Abernethy # Fertility-opportunity hypothesis|Fertility-opportunity theory]]). 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 also to equalize the economic and [[sexual equality|sexual status]] and power of women.
Her theory runs counter to some of the available empirical evidence. For example Iran had a [[Total Fertility Rate]] of 1.82 children per couple in 2005, which is below the replacement rate of 2.1 to 2.3 children per couple needed to maintain population. Iran is widely perceived as a [[patriarchy|patriarchal]] nation, and yet any population growth that occurred there came not from increased birth rates, but from decreased mortality rates, and therefore not from a lack of reproductive rights. Of course, many countries still have high population growth rates while having lower Total Fertility Rates. This is because high population growth in the past has skewed the age demographic in many countries toward a young age, meaning that the population will still rise as the more numerous younger generation approaches maturity.{{Or|date=June 2008}}
"Demographic entrapment" is a concept developed by Maurice King that has not gained widespread acceptance. King argues that this occurs when a country has a population larger than its carrying capacity, no possibility of migration, and exports too little to be able to import food. This will cause starvation. He claims that for example many sub-Saharan nations are or will become stuck in demographic entrapment, instead of having a demographic transition.<ref>{{cite web
|url=http://bmj.bmjjournals.com/cgi/content/full/313/7063/995
|title=Averting a world food shortage: tighten your belts for CAIRO II
|date=[[October 19]] [[1996]]
|publisher=British Medical Journal
}}</ref>
For the world as a whole, the number of [[List of countries and territories by fertility rate|children born per woman]] decreased from 5.02 to 2.65 between 1950 and 2005. A breakdown by continent is as follows:
*[[Europe]] 2.66 to 1.41.
*[[North America]] 3.47 to 1.99.
*[[Oceania]] 3.87 to 2.30.
*[[Central America]] 6.38 to 2.66.
*[[South America]] 5.75 to 2.51.
*[[Asia]] (excluding Middle East) 5.85 to 2.43.
*[[Middle East]] & [[North Africa]] 6.99 to 3.37.
*[[Sub-Saharan Africa]] 6.7 to 5.53.
In 2050, the projected number of children born per woman is 2.05. Only the Middle East & North Africa (2.09) and Sub-Saharan Africa (2.61) will then have numbers greater than 2.<ref>[http://earthtrends.wri.org/searchable_db/results.php?years=1950-1955,1955-1960,1960-1965,1965-1970,1970-1975,1975-1980,1980-1985,1985-1990,1990-1995,1995-2000,2000-2005,2045-2050&variable_ID=369&theme=4&cID=&ccID=0,1,6,2,3,5,8,7,4 World Resources Institute]</ref>
===Population projections from the 1900s to 2050===
United Nations reports, such as [http://www.un.org/popin/ World Population Prospects] state:
* [[World population]] is currently growing by approximately 75 million people per year. Net growth by mid-century is predicted by the United Nations' medium variant to be about 33 million per year. The high projection variant is 92 million, while the low is -13 million. And at the constant fertility variant (current rates) there would be 169 million people added each year by 2050, which would result in a total world population of about 11,858 million people.
* Almost all growth will take place in the less developed regions, where today’s 5.3 billion population of underdeveloped countries is expected to increase to 7.8 billion in 2050. By contrast, the population of the more developed regions will remain mostly unchanged, at 1.2 billion. The world's population is expected to rise by 40% to 9.1 billion.
* In 2000-2005, fertility at the world level stood at 2.65 children per woman, about half the level it had in 1950-1955 (5 children per woman). In the medium variant, global fertility is projected to decline further to 2.05 children per woman.
* During 2005-2050, nine countries are expected to account for half of the world’s projected population increase: [[India]], [[Pakistan]], [[Nigeria]], [[Democratic Republic of the Congo]], [[Bangladesh]], [[Uganda]], [[United States of America]], [[Ethiopia]], and [[China]], listed according to the size of their contribution to population growth.
* Global life expectancy at birth, which is estimated to have risen from 46 years in 1950-1955 to 65 years in 2000-2005, is expected to keep rising to reach 75 years in 2045-2050. In the more developed regions, the projected increase is from 75 years today to 82 years by mid-century. Among the least developed countries, where life expectancy today is just under 50 years, it is expected to be 66 years in 2045-2050.
* The population of 51 countries or areas, including [[Germany]], [[Italy]], [[Japan]] and most of the successor States of the [[former Soviet Union]], is expected to be lower in 2050 than in 2005.
* During 2005-2050, the net number of international migrants to more developed regions is projected to be 98 million. Because deaths are projected to exceed births in the more developed regions by 73 million during 2005-2050, population growth in those regions will largely be due to international migration.
* In 2000-2005, net migration in 28 countries either prevented [[population decline]] or doubled at least the contribution of natural increase (births minus deaths) to population growth. These countries include Austria, Canada, Croatia, Denmark, Germany, Italy, Portugal, Qatar, Singapore, Spain, Sweden, United Arab Emirates and United Kingdom.<ref name = "un.org-pop918">http://www.un.org/News/Press/docs/2005/pop918.doc.html</ref>
* The updated United Nations figures project that the world population will reach 9.2 billion around 2050.<ref>[http://www.un.org/esa/population/publications/longrange2/WorldPop2300final.pdf Microsoft Word - WorldPOP2300.doc<!-- Bot generated title -->]</ref><ref>http://www.un.org/esa/population/unpop.htmm</ref> This is the medium variant figure which assumes a decrease in average fertility from the present level of 2.5 down to 2.
* [[List of countries and territories by fertility rate|Birth rate]]s are now falling in many [[developing country|developing countries]], while the actual populations in many [[developed country|developed countries]] would fall without [[immigration]].<ref>[http://www.un.org/esa/population/unpop.htm United Nations Population Division Home Page<!-- Bot generated title -->]</ref>
* By 2050 (Medium variant), [[India]] will have almost 1.7 billion people, [[China]] 1.4 billion, [[United States]] 400 million, [[Indonesia]] 297 million, [[Pakistan]] 292 million, [[Nigeria]] 289 million, [[Bangladesh]] 254 million, [[Brazil]] 254 million, [[Democratic Republic of the Congo]] 187 million, [[Ethiopia]] 183 million, [[Philippines]] 141 million, [[Mexico]] 132 million, [[Egypt]] 121 million, [[Vietnam]] 120 million, [[Russia]] 108 million, [[Japan]] 103 million, [[Iran]] 100 million, [[Turkey]] 99 million, [[Uganda]] 93 million, [[Tanzania]] 85 million, and [[Kenya]] 85 million.
* '''1900'''
** '''Africa''' - 133 million
** '''Asia''' - 946 million
** '''Europe''' - 408 million
** '''Latin America & Caribbean''' - 74 million
** '''Northern America''' - 82 million
* '''2050'''
** '''Africa''' - 1.9 billion
** '''Asia''' - 5.2 billion
** '''Europe''' - 664 million
** '''Latin America & Caribbean''' - 769 million
** '''Northern America''' - 445 million<ref>[http://esa.un.org/unpp/ World Population Prospects: The 2006 Revision]</ref>
===Birth control===
{{see also|Criticism of the Catholic Church#Opposition to contraception}}
Overpopulation is also related to issues of [[birth control]], with some nations like [[China]] using strict measures in order to reduce birth rates, while religious and ideological opposition to birth control has been cited as a factor contributing to overpopulation and poverty.<ref>{{cite news
|url=http://news.independent.co.uk/world/politics/article2201090.ece
|title=Birth rates 'must be curbed to win war on global poverty'
|publisher=The Independent
|date= [[31 January]] [[2007]]
}}</ref>
There are an estimated 350 million women in the poorest countries of the world who either did not want their last child, do not want another child or want to space their pregnancies, but they lack access to information, affordable means and services to determine the size and spacing of their families. In the [[developing world]], some 514,000 women die of complications from [[pregnancy]] and [[abortion]] on a yearly basis. Additionally, 8 million infants die, many because of [[malnutrition]] or preventable diseases.<ref>[http://findarticles.com/p/articles/mi_m1571/is_46_17/ai_80774574 Q: should the United Nations support more family-planning services for poor countries? | Insight on the News | Find Articles at BNET.com<!-- Bot generated title -->]</ref>
In the United States, in 2001, almost half of pregnancies were unintended.<ref>{{cite journal | author = Finer LB, Henshaw SK | title = Disparities in rates of unintended pregnancy in the United States, 1994 and 2001 | journal = Perspect Sex Reprod Health | year = 2006 | volume = 38 | pages = 90–96 | doi = 10.1363/3809006}}</ref>
As of June 2008, [[Egypt]]ian Minister of Health and Population [[Hatem el-Gabali]] announced that his country has set aside 480 million Egyptian pounds (about 90 million U.S. dollars) to cope with its overpopulation problem through [[family planning]].<ref>[http://www.iol.co.za/index.php?from=rss_Africa&set_id=1&click_id=68&art_id=nw20080611085517622C989460 IOL: Population woes weigh down Egypt]</ref>
==Resources==
[[David Pimentel]],<ref>[http://www.entomology.cornell.edu/IthacaCampus/People/FacultyStaff/Pimentel.html Cornell University Entomology - David Pimentel<!-- Bot generated title -->]</ref> Professor Emeritus at [[Cornell University]], has stated that "With the imbalance growing between population numbers and vital life sustaining resources, humans must actively conserve cropland, freshwater, energy, and biological resources. There is a need to develop renewable energy resources. Humans everywhere must understand that rapid population growth damages the Earth’s resources and diminishes human well-being."<ref>[http://dieoff.org/page174.htm Will Limits Of The Earth'S Resources Control Human Numbers?<!-- Bot generated title -->]</ref><ref>[http://www.worldwatch.org/node/1631 Worldwatch Briefing: Sixteen Dimensions of the Population Problem | Worldwatch Institute<!-- Bot generated title -->]</ref>
These reflect the comments also of the [[United States Geological Survey]] in their paper [http://www.usgs.gov/newsroom/article.asp?ID=653 The Future of Planet Earth: Scientific Challenges in the Coming Century]. "As the global population continues to grow...people will place greater and greater demands on the resources of our planet, including [[mineral]] and [[energy resources]], open space, [[water crisis|water]], and plant and animal resources."
On the other hand, some writers, such as [[Julian Simon]], [[Bjorn Lomborg]] and others of a conservative Libertarian persuasion believe that resources abound for a furtherance of population growth. Population scientists have agreed with their assessments that there are indeed more resources left that would enable continued population growth. However, they warn, this will be at a high cost to the Earth - and thus to us, "the technological optimists are probably correct in claiming that overall world food production can be increased substantially over the next few decades...[however] the environmental cost of what Paul R. and Anne H. Ehrlich describe as 'turning the Earth into a giant human feedlot' could be severe. A large expansion of agriculture to provide growing populations with improved diets is likely to lead to further deforestation, loss of species, soil erosion, and pollution from pesticides and fertilizer runoff as farming intensifies and new land is brought into production."<ref>[http://www.sciam.com/article.cfm?articleID=000F3D47-C6D2-1CEB-93F6809EC5880000&pageNumber=1&catID=2 Misleading Math about the Earth: Scientific American<!-- Bot generated title -->]</ref> Since we are intimately dependent upon the living systems of the Earth,<ref>[http://nasadaacs.eos.nasa.gov/articles/2005/2005_mea.html NASA Earth Science Data and Services: Checking Earth's Vital Signs<!-- Bot generated title -->]</ref><ref>[http://www.greenfacts.org/en/ecosystems/ Ecosystem Change: Scientific Facts on Ecosystem Change<!-- Bot generated title -->]</ref><ref>[http://pubs.usgs.gov/of/2002/of02-349/ USGS OFR 02-349: Human Impact on the Planet: An Earth Science Perspective and Ethical Considerations<!-- Bot generated title -->]</ref> scientists have questioned the wisdom of further expansion.<ref>http://info-pollution.com/lomborg.html</ref>
According to the [[Millennium Ecosystem Assessment]], a four-year research effort by 1,360 of the world’s leading scientists commissioned to measure the actual value of natural resources to humans and the world, "The structure of the world’s ecosystems changed more rapidly in the second half of the twentieth century than at any time in recorded human history, and virtually all of Earth’s ecosystems have now been significantly transformed through human actions."<ref>[http://www.greenfacts.org/en/ecosystems/millennium-assessment-3/1-ecosystem-change.htm#1p1 1. How have ecosystems changed?<!-- Bot generated title -->]</ref> "Ecosystem services, particularly food production, timber and fisheries, are important for employment and economic activity. Intensive use of ecosystems often produces the greatest short-term advantage, but excessive and unsustainable use can lead to losses in the long term. A country could cut its forests and deplete its fisheries, and this would show only as a positive gain to GDP, despite the loss of capital assets. If the full economic value of ecosystems were taken into account in decision-making, their degradation could be significantly slowed down or even reversed."<ref name = "ecosystems-#3">[http://www.greenfacts.org/en/ecosystems/#3 Ecosystem Change: Scientific Facts on Ecosystem Change<!-- Bot generated title -->]</ref><ref>[http://www.greenfacts.org/en/ecosystems/millennium-assessment-3/3-human-wellbeing-poverty.htm#2p0 3. How have ecosystem changes affected human well-being and poverty alleviation?<!-- Bot generated title -->]</ref> The MA blames habitat loss and fragmentation for the continuing disappearance of species.
Another study by the [[United Nations Environment Programme]] (UNEP) called the [[Global Environment Outlook]] [http://www.unep.org/geo/geo4/media/] which involved 1,400 scientists and took five years to prepare comes to similar conclusions. It "found that human consumption had far outstripped available resources. Each person on Earth now requires a third more land to supply his or her needs than the planet can supply." It faults a failure to "respond to or recognise the magnitude of the challenges facing the people and the environment of the planet... 'The systematic destruction of the Earth's natural and nature-based resources has reached a point where the economic viability of economies is being challenged - and where the bill we hand to our children may prove impossible to pay'... The report's authors say its objective is 'not to present a dark and gloomy scenario, but an urgent call to action'. It warns that tackling the problems may affect the vested interests of powerful groups, and that the environment must be moved to the core of decision-making... '<ref>[http://www.unep.org/geo/geo4/media/ Global Environment Outlook: environment for development (GEO-4)]</ref>
Additionally, other issues involving [[quality of life]] - would most people ''want'' to live in a world of billions more people - and the basic right of other species to exist in their native environments come into play.
===Fresh water===
{{See|Water crisis}}
Despite advances in agriculture, the [[fresh water]] supplies that it depends on are running low worldwide.<ref>[http://www.worldwatch.org/node/1661 Population Outrunning Water Supply as World Hits 6 Billion | Worldwatch Institute<!-- Bot generated title -->]</ref><ref>[http://www.amazon.com/dp/0807085723/ Amazon.com: When the Rivers Run Dry: Water-The Defining Crisis of the Twenty-First Century: Books: Fred Pearce<!-- Bot generated title -->]</ref> This [[water crisis]] is only expected to worsen as the population increases. [[Lester R. Brown]] of the [[Earth Policy Institute]] argues that declining water supplies could well have future disastrous consequences for agriculture.<ref>[http://www.amazon.com/dp/0393060705 Amazon.com: Outgrowing the Earth: The Food Security Challenge in an Age of Falling Water Tables and Rising Temperatures: Books: Lester R. Brown<!-- Bot generated title -->]</ref>
However, the amount of freshwater is not necessarily limited to what is currently available in nature. [[Malta]] derives two thirds of its freshwater from [[desalination]] of [[salt water]]. This is an energy-intensive process. One possible solution is large expansion of [[nuclear power]]ed desalination plants. Such plants already exist.<ref>[http://www.uic.com.au/nip74.htm Nuclear Desalination<!-- Bot generated title -->]</ref> Some argue that there are billions of years of nuclear fuel available.<ref name = "stanford-cohen">[http://www-formal.stanford.edu/jmc/progress/cohen.html Facts from Cohen<!-- Bot generated title -->]</ref> Critics point to the high costs of desalination technologies, especially for poor third world countries, the impracticability and cost of transporting or piping massive amounts of desalinated seawater throughout the interiors of large countries, and the "lethal byproduct of saline brine that is a major cause of marine pollution when dumped back into the oceans at high temperatures."<ref>[http://www.thenation.com/doc/20020902/barlow Who Owns Water?<!-- Bot generated title -->]</ref>
One study of the costs of desalination and its transport says that "Indeed, one needs to lift the water by 2000 m, or transport it over more than 1600 km to get transport costs equal to the desalination costs.{{Fact|date=February 2007}}. Desalinated water is expensive in places that are both somewhat far from the sea and somewhat high, such as Riyadh and Harare. In other places, the dominant cost is desalination, not transport. This leads to relatively low costs in places like Beijing, Bangkok, Zaragoza, Phoenix, and, of course, coastal cities like Tripoli." Still, the study, while generally positive about the technology for affluent areas that are proximate to oceans, concludes that "Desalinated water may be a solution for some water-stress regions, but not for places that are poor, deep in the interior of a continent, or at high elevation. Unfortunately, that includes some of the places with biggest water problems."<ref>Evaluating the costs of desalination and water transport. Yuan Zhoua,b, Richard S.J. Tolb,c,d{{PDFlink|[http://www.uni-hamburg.de/Wiss/FB/15/Sustainability/DesalinationFNU41_revised.pdf]|430 [[Kibibyte|KiB]]<!-- application/pdf, 441259 bytes -->}}</ref>
Israel is now desalinating water for a cost of 53 cents per cubic meter.<ref name = "ejpress-water"/> Singapore is desalinating water at a cost of 49 cents per cubic meter.<ref name = "edie-distinct"/>
Newer agricultural technologies do not always require more water usage; for example [[hydroponics]] and [[green house]]s require less.
===Food===
Globally, there is enough food to support the world population, and potential to support many more.{{Fact|date=June 2008}} However, it is not always equally distributed, sometimes resulting in [[famine]] in some areas. A main problem is rather the indirect effect of [[water crisis]] on food production.
More than 100 countries now import [[wheat]]. Some 40 countries import [[rice]]. [[Egypt]] and [[Iran]] rely on imports for 40% of their grain supply. [[Algeria]], [[Japan]], [[South Korea]] and [[Taiwan]] import 70% or more. [[Yemen]] and [[Israel]] import more than 90%. And just 6 countries - the [[US]], [[Canada]], [[France]], [[Australia]], [[Argentina]] and [[Thailand]] - supply 90% of [[grain]] exports. The US alone controls almost half of world grain exports.<ref>[http://www.earth-policy.org/Books/Out/Ote1_5.htm Pushing Beyond the Earth's Limits The Japan Syndrome]</ref><ref>[http://www.i-sis.org.uk/TFBE.php The Food Bubble Economy]</ref>
====Global perspective====
{{see|2007–2008 world food price crisis}}
[[Image:Food production per capita 1961-2005.png|thumb|right|Growth in food production has been greater than population growth. Food per person increased during the 1961-2005 period.]]
The amounts of natural resources in this context are not necessarily fixed, and their distribution is not necessarily a [[zero-sum game]]. For example, due to the [[Green Revolution]] and the fact that more and more land is appropriated each year from wild lands for agricultural purposes, the worldwide production of food has steadily increased faster than population growth. World food production per person was considerably higher in 2005 than 1961.<ref>[http://earthtrends.wri.org/searchable_db/results.php?years=1961-1961,1962-1962,1963-1963,1964-1964,1965-1965,1966-1966,1967-1967,1968-1968,1969-1969,1970-1970,1971-1971,1972-1972,1973-1973,1974-1974,1975-1975,1976-1976,1977-1977,1978-1978,1979-1979,1980-1980,1981-1981,1982-1982,1983-1983,1984-1984,1985-1985,1986-1986,1987-1987,1988-1988,1989-1989,1990-1990,1991-1991,1992-1992,1993-1993,1994-1994,1995-1995,1996-1996,1997-1997,1998-1998,1999-1999,2000-2000,2001-2001,2002-2002,2003-2003,2004-2004,2005-2005&variable_ID=180&theme=8&cID=&ccID=0 # World Resources Institute]</ref>
As world population doubled from 3 billion to 6 billion, daily calorie consumption in poor countries increased from 1,932 to 2,650, and the percentage of people in those countries who were malnourished fell from 45% to 18%. This suggests that Third World poverty and famine are caused by underdevelopment, not overpopulation.<ref>[http://www.economist.com/science/displayStory.cfm?Story_ID=718860 By invitation | The truth about the environment | Economist.com<!-- Bot generated title -->]</ref> However, others question these statistics.<ref>http://www.nicholas.duke.edu/people/faculty/pimm/publications/pimmreprints/170_Pimm_Harvey_Nature.pdf</ref>
The number of people who are overweight has surpassed the number who are malnourished. In a 2006 news story, [[MSNBC]] reported, "There are an estimated 800 million undernourished people and more than a billion considered overweight worldwide."<ref>[http://www.msnbc.msn.com/id/14407969/ Nearly 1 in 5 Chinese overweight or obese - Diet and nutrition - MSNBC.com<!-- Bot generated title -->]</ref>
The [[Food and Agriculture Organization]] of the United Nations states in its report ''The State of Food Insecurity in the World 2006'', that while the number of undernourished people in the developing countries has declined by about three million, a smaller percentage of the populations of developing countries is undernourished today compared with 1990–92: 17 percent against 20 percent. Furthermore, FAO’s projections suggest that the proportion of hungry people in developing countries could be halved from 1990-92 levels to 10 percent by 2015. The FAO also states "We have emphasized first and foremost that reducing hunger is no longer a question of means in the hands of the global community. The world is richer today than it was ten years ago. There is more food available and still more could be produced without excessive upward pressure on prices. The knowledge and resources to reduce hunger are there. What is lacking is sufficient political will to mobilize those resources to the benefit of the hungry." {{PDFlink|[ftp://ftp.fao.org/docrep/fao/009/a0750e/a0750e01.pdf]}}
As of 2008, increased farming for use in [[biofuel]]s,<ref>[http://www.sundayherald.com/news/heraldnews/display.var.2104849.0.2008_the_year_of_global_food_crisis.php 2008: The year of global food crisis]</ref> world [[oil prices]] at over $140 a barrel,<ref>[http://www.csmonitor.com/2008/0118/p08s01-comv.html The global grain bubble]</ref> global [[population growth]],<ref>[http://www.guardian.co.uk/science/2008/mar/07/scienceofclimatechange.food Food crisis will take hold before climate change, warns chief scientist]</ref> [[climate change]],<ref>[http://www.guardian.co.uk/environment/2007/nov/03/food.climatechange Global food crisis looms as climate change and fuel shortages bite]</ref> loss of [[agricultural]] land to residential and industrial development,<ref>[http://www.marketoracle.co.uk/Article3782.html Experts: Global Food Shortages Could ‘Continue for Decades']</ref><ref>[http://www.moyak.com/researcher/resume/papers/var13mkm.html Has Urbanization Caused a Loss to Agricultural Land?]</ref> and growing consumer demand in [[China]] and [[India]]<ref>[http://www.time.com/time/world/article/0,8599,1717572,00.html The World's Growing Food-Price Crisis]</ref> have pushed up the price of [[grain]].<ref>[http://news.bbc.co.uk/1/hi/world/7284196.stm The cost of food: Facts and figures]</ref> [[2007–2008 world food price crisis|Food riot]]s have recently taken place in many countries across the world.<ref>[http://www.guardian.co.uk/world/2007/dec/04/china.business Riots and hunger feared as demand for grain sends food costs soaring]</ref><ref>[http://www.timesonline.co.uk/tol/news/environment/article3500975.ece Already we have riots, hoarding, panic: the sign of things to come?]</ref><ref>[http://www.guardian.co.uk/environment/2008/feb/26/food.unitednations Feed the world? We are fighting a losing battle, UN admits]</ref> An [[epidemic]] of stem rust on [[wheat]] caused by race [[Ug99]] is currently spreading across [[Africa]] and into [[Asia]] and is causing major concern. A virulent wheat disease could destroy most of the world’s main wheat crops, leaving millions to starve. The fungus has spread from Africa to [[Iran]], and may already be in [[Afghanistan]] and [[Pakistan]].<ref>[http://www.guardian.co.uk/science/2007/apr/22/food.foodanddrink Millions face famine as crop disease rages]</ref><ref name = NewSci> {{cite journal | url = http://environment.newscientist.com/channel/earth/mg19425983.700-billions-at-risk-from-wheat-superblight.html
|journal = New Scientist Magazine |title=Billions at risk from wheat super-blight |year=2007-04-03
|accessdate = 2007-04-19 |issue=issue 2598 |pages = 6–7}}</ref><ref>[http://www.alertnet.org/thenews/newsdesk/IRIN/8112190676ab183b80e80199f821ef93.htm IRAN: Killer fungus threatens wheat production in western areas]</ref>
====Africa====
In [[Africa]], if current trends of soil degradation and population growth continue, the continent might be able to feed just 25% of its population by 2025, according to [[United Nations University|UNU]]'s Ghana-based Institute for Natural Resources in Africa.<ref>[http://news.mongabay.com/2006/1214-unu.html Africa may be able to feed only 25% of its population by 2025]</ref>
[[Hunger]] and [[malnutrition]] kill nearly 6 million children a year, and more people are malnourished in [[sub-Saharan Africa]] this decade than in the 1990s, according to a report released by the [[Food and Agriculture Organization]]. In sub-Saharan Africa, the number of malnourished people grew to 203.5 million people in 2000-02 from 170.4 million 10 years earlier says ''The State of Food Insecurity in the World'' report.
According to the BBC, the famine in Zimbabwe was caused by government seizure of farmland.<ref name = "BBC-leaderheld">[http://news.bbc.co.uk/1/hi/world/africa/6439013.stm BBC NEWS | World | Africa | Zimbabwe opposition leader held<!-- Bot generated title -->]</ref> However drought has also played a major role.<ref>[http://www.telegraph.co.uk/news/main.jhtml;jsessionid=EIPPN5WJNBDCPQFIQMFCFGGAVCBQYIV0?xml=/news/2002/04/26/wfamin26.xml Famine disaster threat to 6m in southern Africa - Telegraph<!-- Bot generated title -->]</ref> Thirteen-million people are threatened by famine, in light of the drought in southern Africa. Six-million of them live in Zimbabwe.<ref name = "VOA-famine"> [http://www.voanews.com/uspolicy/archive/2002-09/a-2002-09-03-4-1.cfm MUGABE'S MAN-MADE FAMINE - 2002-09-03<!-- Bot generated title -->]</ref> So that is a contingent of fully half of those potentially threatened by the current food shortages, if indeed they get worse, as is projected. <ref name = "VOA-famine"/> Prior to this combination of drought and seizure of farmland, Zimbabwe had been exporting so much food that it was called "the breadbasket of southern Africa." So other countries were also harmed by these farm seizures.<ref name = "BBC-leaderheld"/> People who study the Zimbabwean famine claim that normally there are more than enough natural resources to feed the people.<ref>[http://www.mises.org/story/1048 Mugabe's Famine - Timothy Terrell - Mises Institute<!-- Bot generated title -->]</ref><ref>[http://observer.guardian.co.uk/international/story/0,6903,837019,00.html Famine becomes Mugabe weapon | International | The Observer<!-- Bot generated title -->]</ref><ref name = "VOA-famine"/> Some claim that the dams and rivers in Zimbabwe are full, and that the famine has nothing to do with drought.<ref>[http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2002/07/28/wzim128.xml Stricken by hunger among the lush fields - Telegraph<!-- Bot generated title -->]</ref> And though it's undoubtedly true that bad governance has exacerbated the famine, still notes the article, "Four weeks without rain at the critical germination phase has led to the failure of [the villagers] small crops. There will be no harvest again until next June."
Prior to President Robert Mugabe's seizure of the farmland in Zimbabwe, the farmers had been using irrigation to deal with drought, but during the seizures of the farmland, much of the irrigation equipment was either vandalized or looted.<ref>[http://www.reliefweb.int/rw/RWB.NSF/db900SID/KHII-6JZ4JG?OpenDocument News: Southern Africa Humanitarian Crisis, Zimbabwe: Mugabe admits chaotic land reforms to blame for food shortages<!-- Bot generated title -->]</ref><ref>[http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2005/09/22/wzim22.xml&sSheet=/portal/2005/09/22/ixportal.html Mugabe strikes his final blow against white farmers - Telegraph<!-- Bot generated title -->]</ref> A 2006 BBC article about Mugabe's seizure of farmland states, "Critics say the reforms have devastated the economy and led to massive hunger. Much of the formerly white-owned land is no longer being productively used - either because the beneficiaries have no experience of farming or they lack finance and tools. Many farms were wrecked when they were invaded by government supporters."<ref>[http://news.bbc.co.uk/1/hi/world/africa/4932060.stm BBC NEWS | World | Africa | Zimbabwe 'asks farmers to return'<!-- Bot generated title -->]</ref>
Israel has 302 people per square kilometre compared with Zimbabwe's 33 people per square kilometre.<ref>http://en.wikipedia.org/wiki/List_of_countries_by_population_density</ref> Although Israel is a desert country with frequent drought and very high population density, it does not have famine. One possible reason why Israel does not have famine{{Or|date=May 2008}} is because its government respects the property rights of farmers, and encourages them to use modern agriculture and irrigation to grow huge amounts of food.<ref>[http://www.newfarm.org/international/israel/sept/index.shtml Seeking life in the desert, on the desert's terms<!-- Bot generated title -->]</ref><ref>[http://www.israel21c.org/bin/en.jsp?enDisplay=view&enDispWhat=object&enZone=Democracy&enDispWho=Articles%5El943&enPage=BlankPage ISRAEL21c<!-- Bot generated title -->]</ref> Still, Israel remains a net importer of food, somewhat detracting from this argument.<ref>[http://www.haaretz.com/hasen/spages/980076.html Food troubles are here to stay - Haaretz - Israel News<!-- Bot generated title -->]</ref> It must also be noted that the high productivity of modern agriculture is currently dependent of the utilization of fossil fuels for pesticide and fuel.<ref> Eating fossil fuels http://www.fromthewilderness.com/free/ww3/100303_eating_oil.html</ref>
[[Mauritius]] is the most densely populated country in Africa.{{Fact|date=May 2008}} It is 10 times more densely populated than most other African countries{{Fact|date=May 2008}}, though at a total population of just 1.23 million, it sits 46th out of Africa's 54 nations for actual population numbers.{{Fact|date=May 2008}} However, [[Mauritius]] does not have famine; on the contrary, it enjoys a First World standard of living.{{Fact|date=May 2008}} The reason [[Mauritius]] is doing so well{{Or|date=May 2008}} is that it has strong protection of property rights, and because it uses science, technology, industrialization, and modernization.<ref name = "heritage-Index-Economic">[http://www.heritage.org/research/features/index/countries.cfm Index of Economic Freedom<!-- Bot generated title -->]</ref>
====Asia====
According to a 2004 article from the BBC, China, the world's most populous country, is suffering from an obesity epidemic.<ref>[http://news.bbc.co.uk/2/hi/asia-pacific/3737162.stm BBC NEWS | Asia-Pacific | Chinese concern at obesity surge<!-- Bot generated title -->]</ref> More recent data indicate China's grain production peaked in the mid 1990s, due to overextraction of [[groundwater]] in the North China plain.<ref>[http://www.greatlakesdirectory.org/zarticles/080902_water_shortages.htm Global Water Shortages May Lead to Food Shortages--Aquifer Depletion]</ref> Nearly half of [[India]]'s children are [[malnourished]], according to recent government data. In [[People's Republic of China|China]], only 8% of children are underweight.<ref>[http://www.cbsnews.com/stories/2007/02/10/ap/health/mainD8N6H7RG0.shtml Survey Says Nearly Half of India's Children Are Malnourished], CBS News</ref> [[Japan]] is facing a potential food crisis that could reduce daily diets to the austere meals of the 1950s, a senior government adviser believes.<ref>[http://www.theaustralian.news.com.au/story/0,20867,19420597-2703,00.html Japan warned of food shortage], The Australian</ref>
====America====
According to a 2007 article from the BBC, scientists at Columbia University have theorized that in the future, densely populated cities such as Mexico City and New York City, which are the largest in North America, may use [[vertical farming]] to grow food on each floor of 30-story skyscrapers.<ref name = "BBC-nyc">[http://news.bbc.co.uk/2/hi/americas/6752795.stm BBC NEWS | Americas | Vertical farming in the big Apple<!-- Bot generated title -->]</ref>
====Population as a function of food availability====
Thinkers such as David Pimentel,<ref>Hopfenberg, Russell and Pimentel, David, "Human Population Numbers as a Function of Food Supply," ''Environment, Development and Sustainability'', vol. 3, no. 1, March, 2001, pp. 1-15</ref> a [[professor]] from [[Cornell University]], [[Virginia Abernethy]],<ref>Abernathy, Virginia, ''Population Politics'' ISBN 0765806037</ref> Alan Thornhill,<ref>''Food Production & Population Growth'', video with Daniel Quinn and Alan Thornhill</ref> Russell Hopffenberg<ref>Hopfenberg, Russell, "Human Carrying Capacity Is Determined by Food Availability," ''Population & Environment'', vol. 25, no. 2, November 2003, pp. 109-117</ref> and author [[Daniel Quinn]]<ref>Quinn, Daniel, ''[[Ishmael (novel)|Ishmael]]'' ISBN 0-553-07875-5</ref> propose that like any 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 argue that every time food production is increased, the population grows. Some human populations throughout history support this theory. Populations of [[hunter-gatherer]]s fluctuate in accordance with the amount of available food. Population increased after the [[Neolithic Revolution]] and an increased food supply. This was followed by subsequent population growth after subsequent [[agricultural revolution]]s.
Critics of this idea point out that birth rates are lowest in the [[developed nation]]s, which also have the highest access to food. In fact, some developed countries have both a diminishing population and an abundant food supply. The United Nations projects that the population of 51 countries or areas, including Germany, Italy, Japan and most of the states of the former Soviet Union, is expected to be lower in 2050 than in 2005.<ref name = "un.org-pop918"/> This shows that human populations do not always grow to match the available food supply; also, many of these countries are major exporters of food. Nevertheless, on the global scale the [[world population]] is increasing<ref>Daniel Quinn in his book, "The Story Of B"</ref>.
====As a result of water deficits====
[[Water deficits]], which are already spurring heavy [[grain]] imports in numerous smaller countries, may soon do the same in larger countries, such as [[China]] or [[India]].<ref>[http://www.atimes.com/atimes/South_Asia/HG21Df01.html Asia Times Online :: South Asia news - India grows a grain crisis<!-- Bot generated title -->]</ref> The water tables are falling in scores of countries (including Northern China, the US, and India) owing to widespread overpumping using powerful diesel and electric pumps. Other countries affected include [[Pakistan]], [[Iran]], and [[Mexico]]. This will eventually lead to water scarcity and cutbacks in grain harvest. Even with the overpumping of its [[aquifers]], China is developing a [[grain]] deficit. When this happens, it will almost certainly drive grain prices upward. Most of the 3 billion people projected to be added worldwide by mid-century will be born in countries already experiencing [[water shortages]]. One suggested solution is for [[population growth]] to be slowed quickly by investing heavily in female [[literacy]] and [[family planning]] services.<ref>[http://www.greatlakesdirectory.org/zarticles/080902_water_shortages.htm Global Water Shortages May Lead to Food Shortages-Aquifer Depletion<!-- Bot generated title -->]</ref> [[Desalination]] is also considered a viable and effective solution to the problem of water shortages.<ref name = "ejpress-water">[http://www.ejpress.org/article/4873 EJP | News | France | French-run water plant launched in Israel<!-- Bot generated title -->]</ref><ref name = "edie-distinct">[http://www.edie.net/news/news_story.asp?id=11402&channel=0 Black & Veatch-Designed Desalination Plant Wins Global Water Distinction<!-- Bot generated title -->]</ref>
After [[China]] and [[India]], there is a second tier of smaller countries with large water deficits — [[Algeria]], [[Egypt]], [[Iran]], [[Mexico]], and [[Pakistan]]. Four of these already import a large share of their grain. Only Pakistan remains self-sufficient. But with a population expanding by 4 million a year, it will also likely soon turn to the world market for grain.<ref>[http://www.i-sis.org.uk/TFBE.php The Food Bubble Economy<!-- Bot generated title -->]</ref>
===Land===
World Resources Institute states that "Agricultural conversion to croplands and managed [[pasture]]s has affected some 3.3 billion [hectares] — roughly 26 percent of the land area. All totaled, agriculture has displaced one-third of temperate and tropical forests and one-quarter of natural grasslands."<ref>{{cite web
|url=http://earthtrends.wri.org/features/view_feature.php?theme=8&fid=34
|title= Domesticating the World: Conversion of Natural Ecosystems
|publisher=World Resources Institute
|date=September 2000
}}</ref><ref>{{cite web
|url=http://earthtrends.wri.org/features/view_feature.php?theme=9&fid=8
|title=Grasslands in Pieces: Modification and Conversion Take a Toll
|publisher=World Resources Institute
|date=December 2000}}</ref> Energy development may also require large areas, like for [[hydroelectric dams]]. Usable land may become less useful through [[salinization]], [[deforestation]], [[desertification]], [[erosion]], and [[urban sprawl]]. Global warming may cause flooding of many of the most productive agricultural areas.{{Fact|date=March 2008}} Thus, available useful land may become a limiting factor. By most estimates, at least half of cultivable land is already being farmed, and there are concerns that the remaining reserves are greatly overestimated.<ref>{{cite web |url=http://www.springerlink.com/content/jurw63588662456x/fulltext.pdf |title=Is there really spare land? A critique of estimates of available cultivable land in developing countries |publisher=Environment, Development, and Sustainability |date=12 January 1999}}</ref>
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 (biology)|hybrid]] plants have larger edible parts (fruit, vegetable, grain) and smaller inedible parts; however, many of the gains of agricultural technology are now historic, with new advances being more difficult to achieve. With new technologies, it is possible to grow crops on some marginal land under certain conditions. [[Aquaculture]] could theoretically 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, although such a process may be very energy-intensive.
Some claim that not all arable land will remain productive if used for [[agriculture]], as they argue that some [[marginal land]] can only be made to produce food by unsustainable practices like [[slash-and-burn]] agriculture. Even with the modern techniques of agriculture, the sustainability of production is in question.
Some scientists have said that in the future, densely populated cities will use [[vertical farming]] to grow food inside skyscrapers.<ref name = "BBC-nyc"/>
Some countries, such as [[Dubai]] have constructed large artificial islands, or have created large dam and dike systems, like the [[Netherlands]], which reclaim land from the water to increase their total land area.<ref>[http://www.dailymail.co.uk/pages/live/articles/news/worldnews.html?in_article_id=463694&in_page_id=1811 Meet the first resident of Dubai's palm-shaped man-made island | the Daily Mail<!-- Bot generated title -->]</ref>
The space taken by a human being itself is not a problem. It has been noted by a number of thinkers - like noted philosopher [[Justin West]] - who deny that overpopulation is a problem - that the entire population of the world could live in Texas (or a land mass the size of Texas). Texas has a total surface area of 261,914 square miles, which is 7.30174326 × 10^12 square feet. Divided by 7 billion (slightly larger than the current population of the world) would yield an average of 1,043 sq feet per person. Were everyone allotted space thusly, a family of 4 would have roughly a 4000 square foot home. This is assuming, of course, single floor houses. Compacted this way, the rest of North America, and all of South America, Europe, Asia, Africa, Australia and Antarctica would be left vacant of human beings and open to farming.
=== Ecological footprint ===
Some groups (for example, the [[World Wide Fund for Nature]]<ref>[http://www.bloomberg.com/apps/news?pid=20601082&sid=asybYkLBp_tk Bloomberg.com: Canada<!-- Bot generated title -->]</ref><ref>[http://www.panda.org/news_facts/publications/living_planet_report/lp_2006/index.cfm WWF - Living Planet Report 2006<!-- Bot generated title -->]</ref> and the [[Global Footprint Network]]<ref>[http://www.footprintnetwork.org/ Global Footprint Network :: HOME - Ecological Footprint - Ecological Sustainability<!-- Bot generated title -->]</ref>) have stated that the [[carrying capacity]] for the human population has been exceeded as measured using the [[ecological footprint]]. Critics question the simplifications and statistical methods employed in calculating ecological footprints. Some argue that there is nothing intrinsically negative about using more land to improve living standards.<ref>http://www.tinbergen.nl/discussionpapers/98105.pdf</ref><ref>[http://www-pam.usc.edu/volume1/v1i1a2print.html Planning and Markets: Peter Gordon and Harry W. Richardson<!-- Bot generated title -->]</ref> On the other hand, proponents would counter that there are many moral dilemmas inherent in geopolitically and temporally inequitable distribution of resources.
=== Energy ===
Population optimists have also been criticized for failing to account for future shortages in [[fossil fuels]], currently used for fertilizer and transportation for modern agriculture. (See [[Hubbert peak]] and [[Future energy development]].) They counter that there will be enough fossil fuels until suitable replacement technologies have been developed, for example hydrogen in a [[hydrogen economy]].<ref>[http://economics.about.com/cs/macroeconomics/a/run_out_of_oil.html Economics, Macroeconomic Resources - Articles<!-- Bot generated title -->]</ref><ref>[http://economics.about.com/cs/macroeconomics/a/run_out_of_oil.htm We Will Never Run Out of Oil<!-- Bot generated title -->]</ref>
In his 1992 book [[Earth in the Balance]], [[Al Gore]] wrote, "... it ought to be possible to establish a coordinated global program to accomplish the strategic goal of completely eliminating the internal combustion engine over, say, a twenty-five-year period..."<ref>[http://www.crossroad.to/articles2/Gore.html Al Gore's Vision of Global Salvation<!-- Bot generated title -->]</ref> Plug in electric cars such as the [[Tesla Roadster]] suggest that Gore's prediction will come true.{{Fact|date=March 2008}} The Earth has enough uranium to provide humans with all of their electricity needs until the sun blows up in 5 billion years, assuming that we develop large scale breeder reactors.<ref name = "stanford-cohen"/>
There has also been increasing development in extracting renewable energy, such as from solar, wind, and tidal energy. If used on a wide scale, these could theoretically fulfill most, if not all, of the energy needs currently being filled by non-renewable resources.{{Fact|date=March 2008}} However, it should be noted that some of these renewable resources also have ecological footprints, though they may be different or smaller than some non-renewable resources. Terrestrial solar and wind power cannot be used for base load generation without some sort of energy storage or transmission over very large geographical areas, since they are transient sources of energy.{{Fact|date=March 2008}}
===Fertilizer===
Modern agriculture uses large amounts of [[fertilizer]]. Since much of this fertilizer is made from [[petroleum]], the problem of [[peak oil]] is of concern. According to a 2003 article in [[Discover magazine]], it is possible to use the process of [[thermal depolymerization]] to manufacture fertilizer out of garbage, sewage, and agricultural waste.<ref>[http://discovermagazine.com/2003/may/featoil/ Anything Into Oil | Alternative Energy | DISCOVER Magazine<!-- Bot generated title -->]</ref> A follow up article from 2006 gave more information.<ref>[http://discovermagazine.com/2006/apr/anything-oil/ Anything Into Oil | Alternative Energy | DISCOVER Magazine<!-- Bot generated title -->]</ref>
=== Wealth and poverty ===
[[Image:Percentage living on less than $1 per day 1981-2001.png|thumb|right|250px|As the world's population has grown, the percentage of the world's population living on less than $1 per day (adjusted for inflation) has halved in twenty years. The graph shows the 1981-2001 period.]]
The [[United Nations]] indicates that about 850 million people are [[malnutrition|malnourished]] or [[starvation|starving]],<ref name = "FAO-Italy">Food and Agriculture Organization of the United Nations. 2001. Food Insecurity: When People Live With Hunger and Fear Starvation. The State of Food insecurity in the World 2001. Italy: FAO</ref> and 1.1 billion people [[water crisis|do not have access to safe drinking water]].<ref name = "Shiklomanov-11-32">I.A. Shiklomanov, ''Appraisal and Assessment of World Water Resources'', Water International 25(1): 11-32 (2000)</ref> Thus some argue that the Earth may support 6 billion people, but only on the condition that many live in misery. Others posit that poverty was worse in the past when the population was smaller, and that worldwide [[poverty]] is declining as the population grows. The percentage of the world's population living on less than $1 per day has halved in twenty years; these are inflation adjusted numbers.<ref>[http://econ.worldbank.org/external/default/main?ImgPagePK=64202990&entityID=000112742_20040722172047&menuPK=64168175&pagePK=64210502&theSitePK=477894&piPK=64210520 The World Bank Group]</ref> Furthermore, a 2007 article from Investor's Business Daily suggests that the population explosion has been accompanied by an increase in worldwide living standards. The article states, "On a per-person basis, real average incomes have more than tripled since 1950 worldwide. And in once-poor areas with the greatest trade liberalization — like East Asia — growth has been even greater, soaring 5,675% from 1950 to 2003."<ref>[http://www.ibdeditorials.com/IBDArticles.aspx?id=267058785139593 IBDeditorials.com: Editorials, Political Cartoons, and Polls from Investor's Business Daily - Free-Trade Fraud<!-- Bot generated title -->]</ref>.
However states the UN Human Development Report from 1997 "During the last 15-20 years, more than 100 developing countries, and several East European countries, have suffered from disastrous growth failures. The reductions in standard of living have been deeper and more long-lasting than what was seen in the industrialised countries during the depression in the 1930s. As a result, the income for more than one billion people has fallen below the level that was reached 10, 20 or 30 years ago." How do some massage the numbers to come up with a rosy picture for the third world? Says Pimm and Harvey "Lomborg’s great optimism about humanity’s future shows up in the way he presents statistics. In sub-Saharan Africa, 'starving people' constituted '38 percent in 1970 … [but only] '33 percent … in 1996. [The percentage
is] expected to fall even further to 30 percent in 2010.' The absolute numbers of starving are curiously missing from these paragraphs. Roughly, the region’s population doubled between 1970 and 1996. To keep the numbers of starving constant, the percentage would have had to have dropped by more than half."<ref>http://www.nicholas.duke.edu/people/faculty/pimm/publications/pimmreprints/170_Pimm_Harvey_Nature.pdf</ref>. In other words, the percentages Lomborg presents would indeed be impressive in an environment with ''no'' population growth, but in one wherein the population has doubled the absolute numbers has actually risen dramatically.<ref>[http://www.greenfacts.org/en/ecosystems/millennium-assessment-3/3-human-wellbeing-poverty.htm#3p0 3. How have ecosystem changes affected human well-being and poverty alleviation?<!-- Bot generated title -->]</ref><ref name = "ecosystems-#3"/>
For example, [[North Korea]] and [[South Korea]] have similar population densities, natural resources, and even parallel cultures (ethnically based in Korean) sharing the same peninsular homeland; but, whereas [[North Korea]] is a poverty-stricken, socialist country where its people are suffering from terrible famine and are destitute,{{Fact|date=March 2008}} [[South Korea]] is a prosperous, capitalist country where the people are well nourished and materially/economically secure{{Fact|date=March 2008}} (without just a small portion of the entire poulation benefiting from the wealth [as do North Korea's Communist Party officials{{Fact|date=March 2008}} with the little wealth their country has] but all the nation's people benefitting from their economic successes) despite the fact that South Korea's population is double that of North Korea's population with a higher fertility rate (hence a faster growing population) as well. This suggests that it is bad economic polices, not "overpopulation," that causes famine. Various [[Indices of Economic Freedom]] suggest that countries with a strong level of economic freedom never have famines or even food shortages, regardless of how high their population densities.<ref name = "heritage-Index-Economic"/>
However, it must be taken into account that most prosperous capitalist countries, with high population densities, are extremely reliant on imports from poorer countries and therefore have not solved the problem of massive poverty, but are assuming a different position in it. Affluent capitalist countries may exceed their own land bases' carrying capacity and rely on poorer countries for resources, production, and labor in order to maintain their level of wealth. It is not the case that affluent countries are effected as negatively by overpopulation as are poorer countries. But, the problem of poverty and overpopulation must be looked at on a global basis and not country by country, as certain countries may very well benefit from the abundance of cheap labor in another country.
===Clean air===
Once a country has industrialized and become wealthy, a combination of government regulation (as one possible choice for effective action) and technological innovation may cause air pollution to decline substantially, even as its population continues to grow. For example, in the United States between 1970 and 2006, the population increased by 42%, inflation adjusted GNP grew by 195%, the number of automobiles more than doubled, and the total number of miles driven increased by 178%. However, according to the [[United States Environmental Protection Agency|Environmental Protection Agency]], during that same time period, there were substantial reductions in total annual emissions of [[carbon monoxide]], [[nitrogen oxides]], [[sulfur dioxide]], [[particulates]], and [[lead]].<ref name = "opinionjournal-Box">[http://www.opinionjournal.com/columnists/pdupont/?id=110008416 The Wall Street Journal Online - Outside the Box<!-- Bot generated title -->]</ref>
==Environment==
Overpopulation has had a major impact on the environment of Earth starting at least as early as the 20th century.<ref>Ron Nielsen, ''The Little Green Handbook: Seven Trends Shaping the Future of Our Planet'', Picador, New York (2006) ISBN 978-0312425814</ref> Many posit that the human population has expanded, enabled by over-exploiting [[natural resources]], with resultant adverse impacts upon [[biodiversity]], aquifer sustainability, [[climate change]] and even human health. There are also indirect economic consequences of this environmental degradation in the form of [[ecosystem services]] attrition.<ref>The New Economy of Nature: The Quest to Make Conservation Profitable (ISBN 1-55963-945-8), Gretchen C. Daily and Katherine Ellison</ref> Beyond the scientifically verifiable harm to the environment, some argue the moral right of other species to simply exist, protected from human exploitation. Says environmental author Jeremy Rifkin, "our burgeoning population and urban way of life have been purchased at the expense of vast ecosystems and habitats. ... It's no accident that as we celebrate the urbanization of the world, we are quickly approaching another historic watershed: the disappearance of the wild."<ref>{{cite news
|url=http://www.thestar.com/opinion/article/164832
|title=The risks of too much city in a crowded world
|publisher=[[Toronto Star]]
|date= [[December 24]] [[2006]]
|first=Jeremy
|last=Rifkin
|accessdate = 2006-12-24
}}</ref>
Says Peter Raven, former President of AAAS (the [[American Association for the Advancement of Science]]) in their seminal work [http://atlas.aaas.org/ AAAS Atlas of Population & Environment], "Where do we stand in our efforts to achieve a sustainable world? Clearly, the past half century has been a traumatic one, as the collective impact of human numbers, affluence (consumption per individual) and our choices of technology continue to exploit rapidly an increasing proportion of the world's resources at an unsustainable rate. ... During a remarkably short period of time, we have lost a quarter of the world's [[topsoil]] and a fifth of its agricultural land, altered the composition of the [[atmosphere]] profoundly, and destroyed a major proportion of our forests and other natural [[habitat]]s without replacing them. Worst of all, we have driven the rate of biological [[extinction]], the permanent loss of species, up several hundred times beyond its historical levels, and are threatened with the loss of a majority of all species by the end of the 21st century."
==Cities==
In 1800 only 3% of the [[world population|world's population]] lived in cities. By the 20th century's close, 47% did so. In 1950, there were 83 cities with populations exceeding one million; but by 2007, this had risen to 468 agglomerations of more than one million.<ref>[http://www.citypopulation.de/World.html Principal Agglomerations of the World]</ref> If the trend continues, the world's [[Metropolis|urban population]] will double every 38 years, say researchers. The UN forecasts that today's urban population of 3.2 billion will rise to nearly 5 billion by 2030, when three out of five people will live in cities.<ref>[http://www.forbes.com/2007/06/11/megacities-population-urbanization-biz-cx_21cities_ml_0611megacities.html Megacities Of The Future]</ref>
The increase will be most dramatic in the poorest and least-urbanised continents, [[Asia]] and [[Africa]]. Surveys and projections indicate that all urban growth over the next 25 years will be in [[developing countries]].<ref>[http://www.energypublisher.com/article.asp?id=5307 Nigeria: Lagos, the mega-city of slums]</ref> One billion people, one-sixth of the world's population, or one-third of urban population, now live in [[shanty towns]],<ref>[http://news.bbc.co.uk/2/hi/science/nature/4561183.stm Half of humanity set to go urban]</ref> which are seen as "breeding grounds" for social problems such as [[crime]], [[drug addiction]], [[alcoholism]], [[poverty]] and [[unemployment]]. In many poor countries [[slums]] exhibit high rates of [[tropical diseases|disease]] due to unsanitary conditions, malnutrition, and lack of basic health care.<ref>[http://www.blackcommentator.com/88/88_reprint_planet_slums.html Planet of Slums - The Third World’s Megacities]</ref>
In 2000, there were 18 [[megacities]] – conurbations such as [[Tokyo]], [[Mexico City]], [[Mumbai]] (Bombay), [[São Paulo]] and [[New York City]] – that have populations in excess of 10 million inhabitants. [[Greater Tokyo]] already has 35 million, more than the entire population of [[Canada]].<ref>[http://www.economist.com/surveys/displaystory.cfm?story_id=9070726 The world goes to town]</ref>
By 2025, according to the ''Far Eastern Economic Review'', Asia alone will have at least 10 hypercities, those with 20 million or more, including [[Jakarta]] (24.9 million people), [[Dhaka]] (25 million), [[Karachi]] (26.5 million), [[Shanghai]] (27 million) and [[Mumbai]] (with a staggering 33 million).<ref>[http://www.atimes.com/atimes/Front_Page/HE20Aa01.html Planet of Slums by Mike Davis]</ref> [[Lagos]] has grown from 300,000 in 1950 to an estimated 15 million today, and the Nigerian government estimates that city will have expanded to 25 million residents by 2015.<ref>[http://www3.nationalgeographic.com/places/cities/city_lagos.html Lagos, Nigeria facts - National Geographic]</ref> Chinese experts forecast that Chinese cities will contain 800 million people by 2020.<ref>[http://english.people.com.cn/200409/16/eng20040916_157275.html China's urban population to reach 800 to 900 million by 2020: expert]</ref>
Despite this increase in population density within the cities and the rise of more megacities, UN [[Habitat]] stated in its reports that if these 2 matters do not negate the fact that city living can be the best solution for dealing with the rising population numbers (and thus still be a good approach on dealing with overpopulation).<ref>[http://news.bbc.co.uk/2/hi/in_depth/6244496.stm UN Habitat calling urban living 'a good thing]</ref> This is because cities concentrate human activity into one place, making the environmental damage on other places smaller. <ref>[http://www.michellenijhuis.com/ National Geographic Magazine; Special report 2008: Changing Climate (Village Green-article by Michelle Nijhuis)]</ref> Letting the cities have a positive influence however, can only be achieved if [[urban planning]] is improved<ref>[http://www.unhabitat.org/content.asp?cid=2523&catid=5&typeid=6&subMenuId=0 Un Habitat calling to rethink urban planning]</ref> and if the city services are properly maintained.
==Ecological footprint by world region==
{{See|List of most overpopulated countries}}
As set forth on page 18 of WWF's Living Planet report, the regions of the world with the greatest ecological footprint<ref>[http://assets.panda.org/downloads/living_planet_report.pdf WWF Living Planet Report 2006]</ref> are ranked as follows:
# North America
# Europe (European Union countries)
# Middle-East and Central Asia
# Asia and Pacific Islands
# Africa
# Europe (Non-European Union countries)
# Latin-America and the Caribbean
Regions are ranked by their per capita consumption of resources. However this ranking may be out-dated, since data were collected in 2003.
==Effects of overpopulation==
Some problems associated with or exacerbated by [[human]] overpopulation:
* '''Inadequate fresh water'''<ref name = "Shiklomanov-11-32"/> for [[drinking water]] use as well as [[sewage treatment]] and [[effluent]] discharge. Some countries, like [[Saudi Arabia]], use energy-expensive [[desalination]] to solve the problem of water shortages.<ref>{{cite web |url=http://www.ejpress.org/article/4873 |title=French-run water plant launched in Israel}}</ref><ref>{{cite web |url=http://www.edie.net/news/news_story.asp?id=11402&channel=0 |title=Black & Veatch-Designed Desalination Plant Wins Global Water Distinction}}</ref>
* '''Depletion of natural resources''', especially [[fossil fuels]]<ref>Hubbert, M.K. ''Techniques of Prediction as Applied to Production of Oil and Gas'', US Department of Commerce, NBS Special Publication 631, May 1982</ref>
* Increased levels of '''[[air pollution]], [[water pollution]], [[soil contamination]] and [[noise pollution]]'''. Once a country has industrialized and become wealthy, a combination of government regulation and technological innovation causes pollution to decline substantially, even as the population continues to grow.<ref name = "opinionjournal-Box"/>
* '''Deforestation and loss of ecosystems'''<ref>* Wilson, E.O., 2002, ''The Future of Life'', Vintage ISBN 0-679-76811-4</ref> that sustain global atmospheric oxygen and carbon dioxide balance; about eight million hectares of forest are lost each year.<ref>{{cite web |url=http://www.mongabay.com/deforestation.htm |title=Worldwide Deforestation Rates}}</ref>
* '''Changes in atmospheric composition and consequent''' [[global warming]]<ref>''International Energy Outlook 2000'', Energy Information Administration, Office of Integrated Analysis and Forecasting, [[U.S. Department of Energy]], Washington D.C. (2000)</ref> <ref>[http://www.pwc.com/extweb/pwcpublications.nsf/docid/dfb54c8aad6742db852571f5006dd532 The world in 2050:Impact of global growth on carbon emissions]</ref>
* Irreversible '''loss of [[arable land]]''' and increases in '''[[desertification]]'''<ref>UNEP, ''Global Environmental Outlook 2000'', Earthscan Publications, London, UK (1999)</ref> Deforestation and desertification can be reversed by adopting property rights, and this policy is successful even while the human population continues to grow.<ref>[http://www.iht.com/articles/2007/02/11/news/niger.php Trees and crops reclaim desert in Niger - International Herald Tribune<!-- Bot generated title -->]</ref>
* '''[[Mass extinctions|Mass species extinctions]]'''.<ref>Leakey, Richard and Roger Lewin, 1996, ''The Sixth Extinction : Patterns of Life and the Future of Humankind'', Anchor, ISBN 0-385-46809-1</ref> from reduced habitat in [[tropical forest]]s due to [[slash-and-burn]] techniques that sometimes are practiced by [[shifting cultivation|shifting cultivators]], especially in countries with rapidly expanding rural populations; present [[extinction]] rates may be as high as 140,000 [[species]] lost per year.<ref>S.L. Pimm, G.J. Russell, J.L. Gittleman and T.M. Brooks, ''The Future of Biodiversity'', Science 269: 347-350 (1995)</ref> The [[IUCN Red List]] lists a total of 698 animal species having gone extinct during recorded human history.<ref>[http://www.iucnredlist.org/info/tables/table3a 2007 IUCN Red List – Summary Statistics for Globally Threatened Species<!-- Bot generated title -->]</ref>
* High '''infant and child mortality'''.<ref>U.S. National Research Council, Commission on the Science of Climate Change, Washington D.C. (2001)</ref> High rates of infant mortality are caused by poverty. Rich countries with high population densities have low rates of infant mortality. [http://en.wikipedia.org/wiki/Image:Infant_mortality_vs.jpg]
* Increased chance of the emergence of '''new [[List of epidemics|epidemic]]s and [[pandemic]]s'''<ref>[http://www.cdc.gov/ncidod/EID/vol11no12/05-0997.htm "Emerging Infectious Diseases" by Mark E.J. Woolhouse and Sonya Gowtage-Sequeria]</ref> For many environmental and social reasons, including overcrowded living conditions, [[malnutrition]] and inadequate, inaccessible, or non-existent [[health care]], the poor are more likely to be exposed to [[Infectious disease#Mortality from infectious_diseases|infectious disease]]s.<ref>[http://www.who.int/infectious-disease-report/pages/ch2text.html WHO Infectious Diseases Report]</ref>
* '''[[Starvation]], [[malnutrition]]'''<ref name = "FAO-Italy"/> or poor diet with ill health and diet-deficiency diseases (e.g. [[rickets]]). [[Famine]] is aggravated by poverty. Rich countries with high population densities do not have famine.<ref>[http://www.jewishworldreview.com/cols/williams022499.asp Walter Williams<!-- Bot generated title -->]</ref><ref name = "overpopulation-faq">[http://www.overpopulation.com/faq/ Overpopulation.Com » FAQ<!-- Bot generated title -->]</ref>
* Poverty coupled with '''inflation''' in some regions and a resulting low level of capital formation. Poverty and inflation are aggravated by bad government and bad economic policies. Many countries with high population densities have eliminated absolute poverty and keep their inflation rates very low.<ref name = "heritage-Index-Economic"/>
* '''Low [[life expectancy]]''' in countries with fastest growing populations<ref>G. McGranahan, S. Lewin, T. Fransen, C. Hunt, M. Kjellen, J. Pretty, C. Stephens and I. Virgin, ''Environmental Change and Human Health in Countries of Africa, the Caribbean and the Pacific'', Stockholm Environment Institute, Stockholm, Sweden (1999)</ref>
* '''Unhygienic living conditions''' for many based upon water resource depletion, discharge of raw sewage<ref>[http://www.dbc.uci.edu/~sustain/suscoasts/krismin.html Wastewater Pollution in China]</ref> and solid waste disposal
* '''Elevated crime rate''' due to drug cartels and increased theft by people stealing resources to survive<ref>American Council for the United Nations University (2002)</ref>
* Conflict over scarce resources and crowding, leading to '''increased levels of warfare'''<ref>Heidelberger Institut fur International Konfliktforschung, ''Konfliktbarometer 2003: 12. Jarlickhe Konfliktanalyse'' University of Heidelberg, Germany (2004)</ref>
==Extraterrestrial population projections==
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''."
In the 1970s, [[Gerard O'Neill]] suggested building [[space habitats]] that could support 30,000 times the carrying capacity of Earth using just the asteroid belt and that the solar system as a whole could sustain current population growth rates for a thousand years.<ref>*[[The High Frontier]] (1976, 2000) [[Gerard O'Neill]], Apogee Books ISBN 1-896522-67-X</ref> [[Marshall Savage]] (1992, 1994) has projected a population of five quintillion throughout the [[solar system]] by 3000, with the majority in the [[asteroid belt]].<ref>[[Marshall Savage]], (1992, 1994) ''[[The Millennial Project: Colonizing the Galaxy in Eight Easy Steps]].'' Little, Brown. ISBN 0-316-77163-5</ref> [[Arthur C. Clarke]], a fervent supporter of Savage, argued that by 2057 there will be humans on the [[Moon]], [[Mars]], [[Europa (moon)|Europa]], [[Ganymede (moon)|Ganymede]], [[Titan (moon)|Titan]] and in orbit around [[Venus]], [[Neptune]] and [[Pluto]].<ref>*Reader's Digest February 2001[http://www.generationterrorists.com/quotes/beyond_2001.html]</ref> [[Freeman Dyson]] (1999) favours the [[Kuiper belt]] as the future home of humanity, suggesting this could happen within a few centuries.<ref>[[Freeman Dyson]], ''The Sun, The Genome, and The Internet'' (1999) Oxford University Press. ISBN 0-19-513922-4</ref> In [[Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets|Mining the Sky]], [[John S. Lewis]] suggests that the staggering resources of the solar system could support 10 quadrillion (10^16) people.
[[K. Eric Drexler]], famous inventor of the futuristic concept of [[Molecular nanotechnology|Molecular Nanotechnology]], has suggested in ''[[Engines of Creation]]'' that colonizing space will mean breaking the [[Malthusian catastrophe|Malthusian limits]] to growth forever for the human species.
Many authors (eg. [[Carl Sagan]], [[Arthur C. Clarke]],<ref>''Greetings, Carbon-Based Bipeds!'' (1999) [[Arthur C. Clarke]], Voyager ISBN 0-00-224698-8</ref> [[Isaac Asimov]]<ref>''The Good Earth Is Dying'' (1971) [[Isaac Asimov]] (published in Der Spiegel)</ref>) have argued that shipping the excess population into space is no solution to human overpopulation, saying that (Clarke, 1999) "''the population battle must be fought or won here on Earth.''" It is not the lack of resources in space that they see as the problem (as books such as [[Mining the sky]] demonstrate<ref>[[Mining the Sky: Untold Riches from the Asteroids, Comets, and Planets|Mining the Sky]] (1996) [[John S. Lewis]]. Addison Wesley. ISBN 0-201-47959-1</ref>); it is the sheer physical impracticality of shipping vast numbers of people into space to "solve" overpopulation on Earth that these authors and others regard as absurd. However, [[Gerard O'Neill]]'s calculations show that the Earth could offload all new population growth with a launch services industry about the same size as the current airline industry in {{cite book|author=O'Neill, Gerard K.|year=1981|title=2081: A Hopeful View of the Human Future|publisher=Simon and Schuster |id=ISBN 0-671-44751-3}}.
==Current amount of overpopulation==
David Pimentel, professor of ecology and [[agriculture]] at [[Cornell University]], and Mario Giampietro, senior researcher at the National Research Institute on Food and Nutrition (INRAN), place in their study ''Food, Land, Population and the U.S. Economy'' the maximum [[U.S. population]] for a [[sustainability|sustainable economy]] at 200 million. To achieve a sustainable economy and avert disaster, the [[United States]] must reduce its population by at least one-third, and [[world population]] will have to be reduced by two-thirds, says the study.<ref>[http://www.energybulletin.net/281.html Eating Fossil Fuels | EnergyBulletin.net]</ref>
In 2006, [[World Wide Fund for Nature|WWF]]'s "[[Living Planet]]" report stated that if we all want to live with a high degree of luxury (European standards), we would be spending three times more than what the planet can supply.<ref>[http://www.panda.org/news_facts/publications/living_planet_report/index.cfm WWF LIving planet report]</ref> In other reports, such as the one cited in the [[The Planet]]-documentary, it is mentioned that we already consume five times more than that the planet can supply, given the current population numbers and our standard of living. Although there is still no real consensus, it is expected that the amount of overpopulation currently lies within this range.
==Overpopulation in popular culture==
===In literature===
In 1729, [[Jonathan Swift]] wrote the satirical essay ''[[A Modest Proposal]]'' where he suggests one solution for both the problem of overpopulation and the growing numbers of undernourished people in Ireland: [[cannibalism]], particularly the raising of infants as food.
[[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. The 1969 ''[[Star Trek: The Original Series]]'' episode entitled [[The Mark of Gideon (TOS episode)|The Mark of Gideon]] dealt with a race of overpopulated aliens who abducted Captain Kirk to solve their population problem.
In the same year, [[John Brunner (novelist)|John Brunner]]'s science-fictional ''[[Stand on Zanzibar]]'' was published. This is perhaps the definitive overpopulation novel to date{{Fact|date=February 2008}}, though [[Harry Harrison]]'s ''[[Make Room! Make Room!]]'' also became a powerful film (''[[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.''<ref>[http://www.imdb.com/title/tt0069530/ Z.P.G. (1972)<!-- Bot generated title -->]</ref> featured an overpopulated, very polluted future Earth, whose [[world government]] practices [[Zero Population Growth]], executing persons who violate the 30-year ban on [[procreation]]. Another 1971 film, called ''The Last Child''<ref>[http://www.imdb.com/title/tt0067326/ The Last Child (1971) (TV)<!-- Bot generated title -->]</ref> also took a stub at laws in the future where families are only allowed to have 1 child and people over 65 are forbidden medical care.
[[J. G. Ballard]]'s story ''[[Billennium]]'' pictures a future in which every individual has four, then just three, square meters of living space. [[Frederik 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 one trillion living in just 100,000 cities on Earth.
A similar point, from the opposite point of view, is made by [[Ursula K. LeGuin]] in the [[utopia]]n part of her novel ''[[Always Coming Home]]'', in which the visiting anthropologist recognises that one of the reasons for the success and stability of the Kesh culture is simply that there are fewer of them (in the post-apocalyptic future) than previously.
[[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.
One of the reasons for this may be the rise of ''environmental fiction'' with ''[[The End of Nature]]'' (1990) by [[Bill McKibben]], the environmental trilogy ''[[Ishmael (novel)|Ishmael]]'' (1992), ''[[The Story of B]]'' (1996), and ''[[My Ishmael]]'' (1997) by [[Daniel Quinn]]. With the host of environmental problems caused by overpopulation, almost by definition, talking about one is talking about the other.
The [[Shadow Children sequence]] is a fictional account of a [[totalitarian]] government attempting to quell overpopulation by exterminating all children born third or later in a family.
===In movies and video===
In the movie and latter video game [[Reign of Fire (film)]] a number of Dragons overpopulate the planet Earth, killing nearly all life before becoming extinct. In this movie it is stated that these creatures have caused at least one massive extinction on earth through overpopulation.
In the video <i>Are We Smarter Than Yeast?</i>, Dan Chay portrays the similarities between our civilisation and those of yeast in regards to overcrowding. <ref>[http://www.pnyv.org/index.php?id=34&tx_ttnews%5Btt_news%5D=931&tx_ttnews%5BbackPid%5D=11&cHash=31a096ffd6]</ref>
==See also==
* [[List of most overpopulated countries|List of overpopulated countries]]
* ''[[National Security Study Memorandum 200]]'' (a U.S. [[National Security Council|NSS]] document from the 1970s)
* [[The Planet]] a detailed documentary on overpopulation
* [[Rientrodolce]] (an Italian interest group which lobbies against overpopulation)
* [[World Population Foundation]]
* ''[[The Ultimate Resource (book)|The Ultimate Resource]]'', a work by [[Julian Simon]] challenging the perceived dangers of overpopulation
===Concepts===
<div style="-moz-column-count:3; column-count:3;">
* [[Carrying capacity]]
* [[Eugenics]]
* [[Ecological footprint]]
* [[Lifeboat ethics]]
* [[Over-consumption]]
* [[Population ageing]]
* [[Population biology]]
* [[Population control]]
* [[Population decline]]
* [[Population density]]
* [[Population ecology]]
* [[Population growth]]
* [[Population pyramid]]
* [[Sustainability]]
* [[Tragedy of the commons]]
* [[Zero population growth]]
</div>
===Global Issues===
{{col-begin}}{{col-3}}
* [[Famine]]
* [[Food security]]
* [[Global warming]]
* [[Epidemic]]s
* [[Immigration]]
* [[Immigration reduction]]
* [[Deforestation]]
* [[Depopulation]]
* [[Desertification]]
{{col-break}}
* [[Diseases of poverty]]
* [[History of medicine#Modern medicine|Medical advances]]
* [[Human migration]]
* [[White flight]]
* [[Urban sprawl]]
* [[Megalopolis (city type)|Megalopolis]]
* [[Holocene extinction event]]
* [[Water crisis]]
* [[Soil erosion]]
{{col-break}}
* [[Green Revolution]]
* [[List of famines]]
* [[Medieval demography]]
* [[List of countries by fertility rate]]
* [[List of countries by population]]
* [[List of countries by population density]]
* [[World energy resources and consumption|World energy consumption]]
* [[Peak oil#Agriculture_and_population_limits|Agriculture and population limits]]
* [[Risks to civilization, humans and planet Earth]]
{{col-end}}
==References==
{{reflist|2}}
==Further reading==
* [[Virginia Abernethy]], professor (emerita) of psychiatry and anthropology, ''Population Politics, (1993)''
* [[Albert Bartlett]], emeritus professor of physics, ''Arithmetic, Population, and Energy: The Forgotten Fundamentals of the Energy Crisis, (1978)''
* [[Joel E. Cohen]], Chair, Laboratory of Populations at the Rockefeller University, ''How Many People Can the Earth Support? (1996)''
* [[Barry Commoner]], American biologist and college professor ''Making Peace with the Planet (1990)''
* [[Herman Daly]], professor at the School of Public Policy at the University of Maryland, College Park ''Ecological Economics and the Ecology of Economics (1999)''
* [[Paul R. Ehrlich]], Bing Professor of Population Studies, ''[[The Population Bomb]], (1968) The Population Explosion, (1990) The Population Bomb, (1995) reprint''
* [[Garrett Hardin]], 1941 Stanford University - Ph.D. Microbiology, ''Living Within Limits'', (1995) reprint
* [[Steven LeBlanc]], ''Constant battles: the myth of the peaceful, noble savage, (2003)'' ISBN 0312310897 argues that local overpopulation has been the major cause of warfare since [[paleolithic]] times.
* [[Andrew Mason]], Professor, head of the University of Hawaii's population studies program, ''Population change and economic development in East Asia: Challenges met, opportunities seized'' (2001)
* [[Donella Meadows]], lead author Ph.D. in biophysics from Harvard, Jorgen Randers, professor of policy analysis at the Norwegian School of Management, [[Dennis Meadows]], director of the Institute for Policy and Social Science Research ''[[Limits to Growth]]: The 30-Year Update'' (Paperback) (2004)
* [[Thomas Malthus]], English demographer and political economist, [http://www.ac.wwu.edu/~stephan/malthus/malthus.0.html''An Essay on the Principle of Population, (1798)'']
* [[Julian Lincoln Simon]], professor of Business Administration ''The Ultimate Resource 2, (1998)"
* [[Ben J. Wattenberg]], senior fellow at the neoconservative American Enterprise Institute, ''The Birth Dearth (1989) ??? Fewer: How the New Demography of Depopulation Will Shape Our Future, (2005)''
* [[Daniel Quinn]], author [[The Story of B]], pp 304-305 (1996)
==External links==
{{Wikiquote|Overpopulation}}
* [http://www.un.org/esa/population/unpop.htm United Nations world population site.] Projections and historical information.
* UN Online databases with selectable variants, either [http://esa.un.org/unpp/index.asp?panel=1 '''basic'''] or [http://esa.un.org/unpp/index.asp?panel=2 '''detailed'''] information.
* [http://www.bbc.co.uk/radio4/reith2007/ "Bursting at the seams", [[Jeffrey Sachs]]'s lectures on overpopulation]
* [http://atlas.aaas.org/ AAAS Atlas of Population and Environment]
* [http://www.earth-policy.org/Updates/2006/Update59.htm U.S. Population Reaches 300 Million, Heading for 400 Million -- No Cause for Celebration]
* [http://www.earth-policy.org/Indicators/Pop/index.htm Earth Policy Institute Resources on POPULATION and HEALTH]
* [http://www.guibord.com/Democracy/FILES-HTML/overpopulation_graph.html Chart: World Population Growth Through History]
* [http://www.voanews.com/english/2006-03-07-voa1.cfm VOA News - World Population Growth to be Concentrated in Developing Nations]
* [http://antwrp.gsfc.nasa.gov/apod/ap030305.html Map over population density]
* [http://www.framingbusiness.net/heilbronerpopulation.htm Is World Population a Concern? Robert Heilbroner, Thomas Malthus, and the Application of Both]
* [http://wolf.readinglitho.co.uk/mainpages/agriculture.html Agriculture - how peak oil could lead to starvation]
* [http://worldpopulationbalance.org/pop/action.php Overpopulation: What you can do.]
*[http://www.nationalgeographic.com/eye/overpopulation/overpopulation.html National Geographic article on overpopulation]
* [http://www.actionbioscience.org/environment/hinrichsen_robey.html Population and the Environment: The Global Challenge]
* [http://www.actionbioscience.org/environment/worldscientists.html World Scientists' Warning to Humanity]
* [http://www.catholiceducation.org/articles/population/pc0001.html Too Many People?] By Dr Jacqueline Kasun
* [http://miraclerosarymission.org/hab280.htm Catholic Social Teaching On Population Growth] An unofficial summary
* [http://www.newadvent.org/cathen/12276a.htm Theories of population] - from the Catholic Encyclopedia
* [http://www.chattoogariver.org/index.php?req=overpopulation&quart=F2002 Article about overpopulation]
* [http://www.globalchange.umich.edu/globalchange2/current/lectures/human_pop/human_pop.html Lecture on population growth over human history]
* [http://www.optimumpopulation.org Optimum Population Trust]
{{population}}
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[[it:Sovrappopolazione]]
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