Population

=== Predicted growth and decline ===
{{Main|Population growth}}
[[File:World population growth - time between each billion-person growth.svg|thumb|upright=1.8|The years taken for every billion people to be added to the world's population, and the years that population was reached (with future estimates).]]

[[Population growth]] increased significantly as the [[Industrial Revolution]] gathered pace from 1700 onwards.<ref name="historic population graphs">As graphically illustrated by [[:File:Poulation-since-10000BC.jpg|population since 10,000BC]] and [[:File:Poulation-since-1000AD.jpg|population since 1000AD]]</ref> The last 50 years have seen a yet more rapid increase in the [[Population growth#Population growth rate|rate]] of population growth<ref name=" historic population graphs " /> due to [[History of medicine#Contemporary medicine|medical advances]] and substantial increases in agricultural productivity, particularly beginning in the 1960s,<ref>{{Cite news |url=http://news.bbc.co.uk/1/hi/world/south_asia/4994590.stm |work=BBC News |title=The end of India's green revolution? |date=29 May 2006 |access-date=29 November 2009 }}</ref> made by the [[Green Revolution]].<ref>[http://www.foodfirst.org/media/opeds/2000/4-greenrev.html Food First/Institute for Food and Development Policy] {{webarchive|url=https://web.archive.org/web/20090714215036/http://www.foodfirst.org/media/opeds/2000/4-greenrev.html |date=14 July 2009 }}</ref> In 2017 the [[United Nations Population Division]] projected that the world's population will reach about 9.8 billion in 2050 and 11.2 billion in 2100.<ref>{{Cite web|url=https://population.un.org/wpp/Publications/Files/WPP2017_KeyFindings.pdf|title=UN Population Prospects 2017}}</ref>

[[File:PRB 2017 Data Sheet Largest Populations.jpg|thumb|left|upright=0.9|PRB 2017 Data Sheet Largest Populations]]

In the future, the world's population is expected to peak,<ref>[http://www.statista.com/statistics/1717/forecast-about-the-development-of-the-world-population/ World Population Development Statistics: Forecast], United Nations, 2011.</ref> after which it will decline due to economic reasons, health concerns, land exhaustion and environmental hazards. According to one report, it is very likely that the world's population will stop growing before the end of the 21st century. Further, there is some likelihood that population will actually decline before 2100.<ref>{{cite journal |title= The End of World Population Growth | volume=412|issue= 6846 |doi=10.1038/35087589 |pmid= 11484054 |journal=Nature |pages=543–545|year= 2001 |last1= Lutz |first1= Wolfgang |last2= Sanderson |first2= Warren |last3= Scherbov |first3= Sergei | bibcode=2001Natur.412..543L| s2cid=4425080| url=http://pure.iiasa.ac.at/id/eprint/6524/1/RR-01-12.pdf}}</ref><ref>{{cite journal | last1 = Ojovan | first1 = M.I. | last2 = Loshchinin | first2 = M.B. | year = 2015 | title = Heuristic Paradoxes of S.P. Kapitza Theoretical Demography | journal = European Researcher | volume = 92 | issue = 3| pages = 237–248 | doi=10.13187/er.2015.92.237| doi-access = free }}</ref> Population has already declined in the last decade or two in Eastern Europe, the Baltics and in the Commonwealth of Independent States.<ref>{{Cite web|url=http://gsociology.icaap.org/report/demsum.html|title=world demographic trends|website=gsociology.icaap.org|access-date=18 July 2019}}</ref>

The population pattern of less-developed regions of the world in recent years has been marked by gradually declining birth rates. These followed an earlier sharp reduction in death rates.<ref name="users.rcn.com">{{cite web |url=http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Populations.html |title=Human Population Growth |access-date=7 April 2009 |url-status=dead |archive-url=https://web.archive.org/web/20090330191122/http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Populations.html |archive-date=30 March 2009  }}</ref> This transition from high birth and death rates to low birth and death rates is often referred to as the [[demographic transition]].<ref name="users.rcn.com" />