Editing Population ageing (section)

{{Short description|Increasing median age in a population}}
{{Use British English|date=May 2015}}
[[File:Global Population-Pyramid-1950-to-2100.jpg|thumb|upright=1.4|World [[population pyramid]] from 1950 to 2100 (projected). (UN, World Population Prospects 2017)]]
[[File:Population by broad age group projected to 2100, OWID.svg|thumb|upright=1.4|World age group populations from 1950 to 2100 (projected).<ref name="q917">{{cite web | title=Population by age group | website=Our World in Data | url=https://ourworldindata.org/grapher/population-by-age-group | access-date=26 January 2025}}</ref>]]
'''Population ageing''' is an overall change in the ages of a [[population]]. This can typically be summarised in a single parameter as an increase in the [[median age]]. Causes are a long-term decline in [[fertility rates]] and a decline in [[mortality rate]]s. Most countries now have declining mortality rates and an ageing population: trends that emerged first in [[developed countries]] but are now also seen in virtually all [[developing countries]]. In most developed countries, population ageing started in the late 19th century. By the late 20th century, the world population as a whole was also ageing. The proportion of people aged 65 and above accounts for 6% of the total population.{{when|date=April 2025}} This reflects a historic overall decline in the world's average fertility rate.<ref>{{Cite book |url=https://www.worldcat.org/title/390135418 |title=International handbook of population aging |date=2009 |publisher=Springer |isbn=978-1-4020-8355-6 |editor-last=Uhlenberg |editor-first=Peter |series=International handbooks of population |location=Dordrecht ; London |oclc=390135418}}</ref> That is the case for every country in the world except the 18&nbsp;countries designated as "demographic outliers" by the [[United Nations]].<ref name="devrep05">{{cite book|url=https://archive.org/details/humandevelopment0000unse_y0c2|title=UN Human Development Report 2005, International Cooperation at a Crossroads-Aid, Trade and Security in an Unequal World|date=September 2005|publisher=United Nations Development Programme|format=PDF|isbn=978-0-19-530511-1|author=United Nations Development Programme|url-access=registration}}</ref>{{Failed verification|date=September 2018}} The aged population is currently at its highest level in human history.<ref name="WPA-UN">[https://www.un.org/esa/population/publications/worldageing19502050/ World Population Ageing: 1950-2050], United Nations Population Division.</ref> The UN projects that the population will age faster in the 21st&nbsp;century than in the 20th.<ref name="WPA-UN" /> The number of people aged 60 years and over has tripled since 1950; it reached 600 million in 2000 and surpassed 700 million in 2006. It is projected that the combined senior and [[geriatric]] population will reach 2.1 billion by [[2050#World population|2050]].<ref>{{Cite journal
| last = Chucks
| first = J
| date = July 2010
| title = Population Ageing in Goa: Research Gaps and the Way Forward
| journal = Journal of Aging Research
| volume = 2010
| pages = 672157
| doi = 10.4061/2010/672157
| pmid = 21188229
| pmc = 3003962
| doi-access = free
}}</ref><ref name=":0">{{Cite journal
| last1 = Issahaku
| first1 = Paul
| last2 = Neysmith
| first2 = Sheila
| date = 2013
| title = Policy Implications of Population Ageing in West Africa
| journal = International Journal of Sociology and Social Policy
| volume = 33
| issue = 3/4
| pages = 186–202
| doi = 10.1108/01443331311308230
}}</ref> Countries vary significantly in terms of the degree and pace of ageing, and the UN expects populations that began ageing later will have less time to respond to its implications.<ref name="WPA-UN" /> Policy interventions include preventative strategies that increase the size of the young, working-age population, as well as adaptive measures to make overarching systems compatible with a new demographic future.