Editing War (section)

===Demographic===
<!-- This section is linked from [[The Clash of Civilizations|Clash of Civilizations]] -->

Demographic theories can be grouped into two classes, Malthusian and youth bulge theories:

====Malthusian====

[[Malthusian catastrophe|Malthusian theories]] see expanding population and scarce resources as a source of violent conflict. [[Pope Urban II]] in 1095, on the eve of the [[First Crusade]], advocating Crusade as a solution to European overpopulation, said:
{{quote|For this land which you now inhabit, shut in on all sides by the sea and the mountain peaks, is too narrow for your large population; it scarcely furnishes food enough for its cultivators. Hence it is that you murder and devour one another, that you wage wars, and that many among you perish in civil strife. Let hatred, therefore, depart from among you; let your quarrels end. Enter upon the road to the Holy Sepulchre; wrest that land from a wicked race, and subject it to yourselves.<ref>{{cite book |title=Lend me your ears: great speeches in history |first=William |last=Safire |publisher=[[W. W. Norton & Company]] |year=2004 |isbn=978-0-393-05931-1 |page=94}}</ref>}}

This is one of the earliest expressions of what has come to be called the Malthusian theory of war, in which wars are caused by expanding populations and limited resources. [[Thomas Malthus]] (1766–1834) wrote that populations always increase until they are limited by war, disease, or [[famine]].<ref>{{cite book |title=Geography: an integrated approach |first=David |last=Waugh |publisher=[[Nelson Thornes]] |year=2000 |isbn=978-0-17-444706-1 |page=378}}</ref> The violent [[herder–farmer conflicts in Nigeria]], [[Mali]], [[Sudanese nomadic conflicts|Sudan]] and other countries in the [[Sahel]] region have been exacerbated by [[land degradation]] and population growth.<ref>{{cite news |title=In Mali, waning fortunes of Fulani herders play into Islamist hands |url=https://www.reuters.com/article/us-mali-fulani/in-mali-waning-fortunes-of-fulani-herders-play-into-islamist-hands-idUSKBN13F0L2 |work=Reuters |date=20 November 2016 |access-date=31 March 2019 |archive-date=30 March 2019 |archive-url=https://web.archive.org/web/20190330131908/https://www.reuters.com/article/us-mali-fulani/in-mali-waning-fortunes-of-fulani-herders-play-into-islamist-hands-idUSKBN13F0L2 |url-status=live }}</ref><ref>{{cite news |title=How Climate Change Is Spurring Land Conflict in Nigeria |url=https://time.com/5324712/climate-change-nigeria/ |magazine=Time |date=28 June 2018 |access-date=31 March 2019 |archive-date=4 March 2021 |archive-url=https://web.archive.org/web/20210304231237/https://time.com/5324712/climate-change-nigeria/ |url-status=live }}</ref><ref>{{cite news |title=The Deadliest Conflict You've Never Heard of |url=https://www.foreignaffairs.com/articles/nigeria/2019-01-23/deadliest-conflict-youve-never-heard |work=[[Foreign Policy]] |date=23 January 2019 |access-date=31 March 2019 |archive-date=18 February 2019 |archive-url=https://web.archive.org/web/20190218125507/https://www.foreignaffairs.com/articles/nigeria/2019-01-23/deadliest-conflict-youve-never-heard |url-status=live }}</ref>

====Youth bulge====
[[File:2017 world map, median age by country.svg|thumb|upright=1.4|[[Population pyramid|Median age]] by country. War reduces life expectancy. A youth bulge is evident for [[Demographics of Africa|Africa]], and to a lesser extent in some countries in West Asia, South Asia, Southeast Asia and Central America.]]

According to [[Gunnar Heinsohn|Heinsohn]], who proposed [[youth bulge]] theory in its most generalized form, a youth bulge occurs when 30 to 40 percent of the males of a nation belong to the "fighting age" cohorts from 15 to 29 years of age. It will follow periods with [[total fertility rate]]s as high as 4–8 children per woman with a 15–29-year delay.<ref>Helgerson, John L. (2002): "The National Security Implications of Global Demographic Trends"[http://www.au.af.mil/au/awc/awcgate/cia/helgerson2.htm] {{Webarchive|url=https://web.archive.org/web/20171010064934/http://www.au.af.mil/au/awc/awcgate/cia/helgerson2.htm|date=10 October 2017}}</ref><ref>Heinsohn, G. (2006): "Demography and War" [https://de.scribd.com/doc/310263543/Gunnar-Heinsohn-Demography-and-War (online)] {{Webarchive|url=https://web.archive.org/web/20160512185458/https://de.scribd.com/doc/310263543/Gunnar-Heinsohn-Demography-and-War |date=12 May 2016 }}</ref> Heinsohn saw both past "Christianist" European colonialism and imperialism, as well as today's Islamist civil unrest and terrorism as results of high birth rates producing youth bulges.<ref>Heinsohn, G. (2005): "Population, Conquest and Terror in the 21st Century" [https://de.scribd.com/doc/310265022/Gunnar-Heinsohn-Population-Conquest-and-Terror-in-the-21st-Century (online)] {{Webarchive|url=https://web.archive.org/web/20160513082119/https://de.scribd.com/doc/310265022/Gunnar-Heinsohn-Population-Conquest-and-Terror-in-the-21st-Century |date=13 May 2016 }}</ref> 

Among prominent historical events that have been attributed to youth bulges are the role played by the historically large youth cohorts in the rebellion and revolution waves of early modern Europe, including the [[French Revolution]] of 1789,<ref>{{cite book|author=Jack A. Goldstone|title=Revolution and Rebellion in the Early Modern World|url=https://books.google.com/books?id=M-T9dR7nWDUC|access-date=31 May 2012|date= 1993|publisher=University of California Press|isbn=978-0-520-08267-0|archive-date=26 May 2013|archive-url=https://web.archive.org/web/20130526133145/http://books.google.com/books?id=M-T9dR7nWDUC|url-status=live}}</ref> and the effect of economic depression upon the largest German youth cohorts ever in explaining the rise of [[Nazism]] in Germany in the 1930s.<ref>Moller, Herbert (1968): 'Youth as a Force in the Modern World', ''Comparative Studies in Society and History'' 10: 238–60; 240–44</ref> The 1994 [[Rwandan genocide]] has also been analyzed as following a massive youth bulge.<ref>Diessenbacher, Hartmut (1994): ''Kriege der Zukunft: Die Bevölkerungsexplosion gefährdet den Frieden''. Muenchen: Hanser 1998; see also (criticizing youth bulge theory) Marc Sommers (2006): "Fearing Africa's Young Men: The Case of Rwanda." The World Bank: Social Development Papers – Conflict Prevention and Reconstruction, Paper No. 32, January 2006 [http://www.eldis.org/vfile/upload/1/document/0708/DOC21389.pdf] {{Webarchive|url=https://web.archive.org/web/20171010064638/http://www.eldis.org/vfile/upload/1/document/0708/DOC21389.pdf|date=10 October 2017}}</ref> Youth bulge theory has been subjected to statistical analysis by the World Bank,<ref>[[Henrik Urdal|Urdal, Henrik]] (2004): "The Devil in the Demographics: The Effect of Youth Bulges on Domestic Armed Conflict", [https://web.archive.org/web/20041118212538/http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2004/07/28/000012009_20040728162225/Rendered/PDF/29740.pdf],</ref> [[Population Action International]],<ref>Population Action International: "The Security Demographic: Population and Civil Conflict after the Cold War"[http://pai.org/wp-content/uploads/2012/01/The_Security_Demographic_Population_and_Civil_Conflict_After_the_Cold_War-1.pdf] {{Webarchive|url=https://web.archive.org/web/20171010064933/http://pai.org/wp-content/uploads/2012/01/The_Security_Demographic_Population_and_Civil_Conflict_After_the_Cold_War-1.pdf|date=10 October 2017}}</ref> and the [[Berlin Institute for Population and Development]].<ref>Kröhnert, Steffen (2004): "Warum entstehen Kriege? Welchen Einfluss haben demografische Veränderungen auf die Entstehung von Konflikten?" [http://www.berlin-institut.org/fileadmin/user_upload/Jugend_und_Kriegsgefahr/Warum_entstehen_Kriege.pdf] {{Webarchive|url=https://web.archive.org/web/20180904230108/https://www.berlin-institut.org/fileadmin/user_upload/Jugend_und_Kriegsgefahr/Warum_entstehen_Kriege.pdf|date=4 September 2018}}</ref> Youth bulge theories have been criticized as leading to racial, gender and age discrimination.<ref>Hendrixson, Anne: "Angry Young Men, Veiled Young Women: Constructing a New Population Threat" [http://www.thecornerhouse.org.uk/item.shtml?x=85999] {{Webarchive|url=https://web.archive.org/web/20100530200503/http://www.thecornerhouse.org.uk/item.shtml?x=85999|date=30 May 2010}}</ref>