《联合国：2022年世界人口展望报告（英文版）（页）.pdf》由会员分享，可在线阅读，更多相关《联合国：2022年世界人口展望报告（英文版）（页）.pdf（50页珍藏版）》请在三个皮匠报告上搜索。

1、WorldPopulationProspects2022Summary of Results UN DESA/POP/2021/TR/NO.3Department of Economic and Social AffairsPopulation DivisionWorld Population Prospects 2022Summary of ResultsUnited NationsNew York,2022United Nations Department of Economic and Social Affairs,Population DivisionThe Department of

2、 Economic and Social Affairs of the United Nations Secretariat is a vital interface between global policies in the economic,social and environmental spheres and national action.The Department works in three main interlinked areas:(i)it compiles,generates and analyses a wide range of economic,social

3、and environmental data and information on which States Members of the United Nations draw to review common problems and take stock of policy options;(ii)it facilitates the negotiations of Member States in many intergovernmental bodies on joint courses of action to address ongoing or emerging global

4、challenges;and(iii)it advises interested Governments on the ways and means of translating policy frameworks developed in United Nations conferences and summits into programmes at the country level and,through technical assistance,helps build national capacities.The Population Division of the Departm

5、ent of Economic and Social Affairs provides the international community with timely and accessible population data and analysis of population trends and development outcomes for all countries and areas of the world.To this end,the Division undertakes regular studies of population size and characteri

6、stics and of all three components of population change(fertility,mortality and migration).Founded in 1946,the Population Division provides substantive support on population and development issues to the United Nations General Assembly,the Economic and Social Council and the Commission on Population

7、and Development.It also leads or participates in various interagency coordination mechanisms of the United Nations system.The work of the Division also contributes to strengthening the capacity of Member States to monitor population trends and to address current and emerging population issues.Sugges

8、ted citationUnited Nations Department of Economic and Social Affairs,Population Division(2022).World Population Prospects 2022:Summary of Results.UN DESA/POP/2022/TR/NO.3.This report is available in electronic format on the Divisions website at www.unpopulation.org.For further information about this

9、 report,please contact the Office of the Director,Population Division,Department of Economic and Social Affairs,United Nations,New York,10017,USA,by Fax:1 212 963 2147 or by email at populationun.org.Copyright informationFront cover:“Singapore Management University Students Attend Secretary-General

10、Lecture”UN Photo/Eskinder Debebe-Lecture.Back cover:“School Opens in Weapons Free Zone East of UNMISS”UN Photo/Amanda Voisard.United Nations PublicationSales No.:E.22.XIII.3ISBN:978-92-1-148373-4eISBN:9789210014380 Copyright United Nations,2022.Figures and tables in this publication can be reproduce

11、d without prior permission under a Creative Commons license(CC BY 3.0 IGO),http:/creativecommons.org/licenses/by/3.0/igo/.AcknowledgementsThis report was prepared by Victor Gaigbe-Togbe,Lina Bassarsky,Danan Gu,Thomas Spoorenberg and Lubov Zeifman.The authors wish to thank John Wilmoth,Bela Hovy and

12、Stephen Kisambira for reviewing the draft.The World Population Prospects 2022 data were prepared by a team led by Patrick Gerland,including Guiomar Bay,Helena Cruz Castanheira,Giulia Gonnella,Danan Gu,Sara Hertog,Yumiko Kamiya,Vladimra Kantorov,Pablo Lattes,Kyaw Kyaw Lay,Franois Pelletier,Jos H.C.Mo

13、nteiro da Silva,Igor Ribeiro,Thomas Spoorenberg,Mark Wheldon,Ivn Williams and Lubov Zeifman,with the assistance of Gabriel Borges,Dennis Butler,Rafaella Carnevali,Fengqing Chao,Jorge Cimentada,Sam Clark,Camille Dorion,Brian Houle,Peter Johnson,Shelmith Kariuki,Sabu Kunju,Nan Li,Peiran Liu,Jonathan M

14、uir,Marlia Nepomuceno,Marius Pascariu,Adrian Raftery,Mariana Urbina Ramirez,Tim Riffe,Bruno Schoumaker,and Hana evkov.The team is grateful to other colleagues in the Population Division for the support they have provided,as well as colleagues from the Latin American and Caribbean Demographic Centre,

15、Population Division of the United Nations Economic Commission for Latin America and the Caribbean(ECLAC),the Demographic Statistics Section of the Statistics Division of the United Nations Department of Economic and Social Affairs,and the teams of the United Nations Inter-Agency Group for Child Mort

16、ality Estimation(UN IGME)and the WHO-UN DESA Technical Advisory Group on COVID Mortality Assessment for their inputs and continuous support.The assistance of Bintou Papoute Ouedraogo and Neena Koshy in editing and desktop publishing is acknowledged.ContentsKey messages.iIntroduction.1I.A century of

17、world population trends:1950 to 2050.3II.Trends in fertility,mortality and international migration.13III.Long-range population projections to 2100.27Annex:Whats new in the 2022 revision?.35References.37Notes on regions,development groups,countries or areasThe designations employed in this publicatio

18、n and the material presented in it do not imply the expression of any opinions whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country,territory,city or area or of its authorities,or concerning the delimitation of its frontiers or boundaries.The ter

19、m“country”as used in this report also refers,as appropriate,to territories or areas.In this publication,data for countries and areas have been aggregated in six continental regions:Africa,Asia,Europe,Latin America and the Caribbean,Northern America,and Oceania.Further information on continental regi

20、ons is available from https:/unstats.un.org/unsd/methodology/m49/.Countries and areas have also been grouped into geographic regions based on the classification being used to track progress in achieving the Sustainable Development Goals of the United Nations(see:https:/unstats.un.org/sdgs/indicators

21、/regional-groups).The designation of“more developed”and“less developed”,or“developed”and“developing”,is intended for statistical purposes and does not express a judgment about the stage in the development process reached by a particular country or area.More developed regions comprise all countries a

22、nd areas of Europe and Northern America,plus Australia,New Zealand and Japan.Less developed regions comprise all countries and areas of Africa,Asia(excluding Japan),Latin America and the Caribbean,and Oceania(excluding Australia and New Zealand).The group of least developed countries(LDCs)includes 4

23、6 countries,located in sub-Saharan Africa(32),Northern Africa and Western Asia(2),Central and Southern Asia(4),Eastern and South-Eastern Asia(4),Latin America and the Caribbean(1),and Oceania(3).Further information is available at http:/unohrlls.org/about-ldcs/.The group of landlocked developing cou

24、ntries(LLDCs)includes 32 countries or territories,located in sub-Saharan Africa(16),Northern Africa and Western Asia(2),Central and Southern Asia(8),Eastern and South-Eastern Asia(2),Latin America and the Caribbean(2),and Europe and Northern America(2).Further information is available at http:/unohr

25、lls.org/about-lldcs/.The group of small island developing States(SIDS)includes 58 countries or territories,located in the Caribbean(29),the Pacific(20),and the Atlantic,Indian Ocean,Mediterranean and South China Sea(AIMS)(9).Further information is available at http:/unohrlls.org/about-sids/.The clas

26、sification of countries and areas by income level is based on gross national income(GNI)per capita as reported by the World Bank(2022).These income groups are not available for all countries and areas.Further information is available at:https:/datahelpdesk.worldbank.org/knowledgebase/articles/906519

27、-world-bank-country-and-lending-groups.Definition of acronymsAIDS acquired immune deficiency syndromeAPI Application Programming Interface ART antiretroviral treatments ASFR age-specific fertility rateCOVID-19 coronavirus disease 2019CRVS civil registration and vital statistics ECLAC Economic Commis

28、sion for Latin America and the CaribbeanGDP gross domestic productHIV human immunodeficiency virusICPD International Conference on Population and DevelopmentIHME Institute of Health Metrics and EvaluationISCED International Standard Classification of EducationJRC Joint Research Center LDCs least dev

29、eloped countriesLLDC landlocked developing countries OECD Organization for Economic Co-operation and DevelopmentPES post-enumeration surveyPPP purchasing power parity SDGs Sustainable Development GoalsSIDS small island developing StatesSSPs shared socio-economic pathwaysTFR total fertility rateUN DE

30、SA United Nations Department of Economic and Social AffairsUN IGME United Nations Inter-Agency Group for Child Mortality EstimationUNESCO United Nations Educational,Scientific and Cultural OrganizationUNHCR United Nations High Commissioner for RefugeesUNICEF United Nations Childrens FundWHO World He

31、alth OrganizationWorld Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population DivisioniKey messagesThe worlds population continues to grow,but the pace of growth is slowing down The worlds population is projected to reach 8 billion on 15 Novem

32、ber 2022.The latest projections by the United Nations suggest that the global population could grow to around 8.5 billion in 2030,9.7 billion in 2050 and 10.4 billion in 2100.Population growth is caused in part by declining levels of mortality,as reflected in increased levels of life expectancy at b

33、irth.Globally,life expectancy reached 72.8 years in 2019,an increase of almost 9 years since 1990.Further reductions in mortality are projected to result in an average longevity of around 77.2 years globally in 2050.Life expectancy at birth for women in 2019 exceeded that for men by 5.4 years global

34、ly,with female and male life expectancies standing at 73.8 and 68.4,respectively.A female survival advantage is observed in all regions and countries,ranging from 7 years in Latin America and the Caribbean to 2.9 years in Australia and New Zealand.Following a drop in mortality,population growth cont

35、inues so long as fertility remains at high levels.When fertility begins to fall,the annual rate of growth starts to drop.In 2021,the average fertility of the worlds population stood at 2.3 births2 per woman over a lifetime,having fallen from about 5 births per woman in 1950.Global fertility is proje

36、cted to decline further to 2.1 births per woman by 2050.In 2020,the global population growth rate fell under 1 per cent per year for the first time since 1950.The worlds population is projected to reach a peak of around 10.4 billion people during the 2080s and to remain at that level until 2100.Two-

37、thirds of the projected increase in global population through 2050 will be driven by the momentum of past growth that is embedded in the youthful age structure of the current population.Such growth would occur even if childbearing in todays high-fertility countries were to fall immediately to around

38、 two births per woman.Given that most population increase until 2050 will be driven by the momentum of past growth,further actions by Governments aimed at reducing fertility would do little to slow the pace of growth between now and mid-century,beyond the gradual slowdown indicated by the projection

39、s presented here.Nevertheless,the cumulative impact of such changes could contribute to a more substantial reduction of global population growth in the second half of the century.Sustained high fertility and rapid population growth present challenges to the achievement of sustainable development.The

40、 necessity of educating growing numbers of children and young people,for example,draws resources away from efforts to improve the quality of education.For countries with continuing high levels of fertility,achieving the Sustainable Development Goals(SDGs),particularly those related to health,educati

41、on and gender,is likely to hasten the transition towards lower fertility and slower population growth.Rates of population growth vary significantly across countries and regions In 2022,the two most populous regions were both in Asia:Eastern and South-Eastern Asia with 2.3 billion people(29 per cent

42、of the global population),and Central and Southern Asia with 2.1 billion(26 per cent).China and India,with more than 1.4 billion each,accounted for most of the population in these two regions.More than half of the projected increase in global population up to 2050 will be concentrated in just eight

43、countries:the Democratic Republic of the Congo,Egypt,Ethiopia,India,Nigeria,Pakistan,the Philippines and the United Republic of Tanzania.Disparate growth rates among the worlds largest countries will re-order their ranking by size.India is projected to surpass China as the worlds most populous count

44、ry during 2023.Countries of sub-Saharan Africa are expected to continue growing through 2100 and to contribute more than half of the global population increase anticipated through 2050.1 In this report,births refer to live births.World Population Prospects 2022:Summary of ResultsUnited Nations Depar

45、tment of Economic and Social Affairs,Population Divisionii Whereas the populations of Australia and New Zealand,Northern Africa and Western Asia,and Oceania(excluding Australia and New Zealand)are expected to experience slower,but still positive,growth through the end of the century,the populations

46、of Eastern and South-Eastern Asia,Central and Southern Asia,Latin America and the Caribbean,and Europe and Northern America are projected to reach their peak size and to begin to decline before 2100.The 46 least developed countries(LDCs)are among the worlds fastest-growing.Many are projected to doub

47、le in population between 2022 and 2050,putting additional pressure on resources and posing challenges to the achievement of the Sustainable Development Goals(SDGs).For many countries and areas,including some small island developing States(SIDS),the challenges posed by rapid growth are compounded by

48、their vulnerability to climate change and sea-level rise.Levels and patterns of fertility and mortality vary widely around the world The gap in life expectancy at birth between certain groups of countries remains wide.In 2021,life expectancy in the least developed countries lagged 7.0 years behind t

49、he global average,due largely to persistently high levels of child and maternal mortality and,in some countries,to violence and conflict or to the continuing impact of the human immunodeficiency virus(HIV)epidemic.In 2021,fertility levels high enough to sustain positive population growth were found

50、in sub-Saharan Africa(4.6 births per woman),Oceania excluding Australia and New Zealand(3.1),Northern Africa and Western Asia(2.8),and Central and Southern Asia(2.3).Some countries,including several in sub-Saharan Africa and in Latin America and the Caribbean,continue to experience high levels of ad

51、olescent fertility,with potential adverse consequences for the health and well-being of both the young mothers and their children.In 2021,13.3 million babies,or about 10 per cent of the total worldwide,were born to mothers under 20 years old.The population of older persons is increasing both in numb

52、ers and as a share of the total The share of the global population aged 65 years or above is projected to rise from 10 per cent in 2022 to 16 per cent in 2050.By 2050,the number of persons aged 65 years or over worldwide is projected to be more than twice the number of children under age 5 and about

53、 the same as the number of children under age 12.Whereas population growth at older ages is driven by lower mortality and increased survival,an upward shift in the population age distribution is caused by a sustained drop in the fertility level.Because of the female advantage in life expectancy,wome

54、n outnumber men at older ages in almost all populations.Globally,women comprised 55.7 per cent of persons aged 65 or older in 2022,and their share is projected to decline slightly to 54.5 per cent by 2050.Countries with ageing populations should take steps to adapt public programmes to the growing p

55、roportion of older persons,including by improving the sustainability of social security and pension systems and by establishing universal health care and long-term care systems.A sustained drop in fertility leads to an increased concentration of the population at working ages,creating an opportunity

56、 for accelerated economic growth per capita In most countries of sub-Saharan Africa,as well as in parts of Asia and Latin America and the Caribbean,the share of population at working ages(between 25 and 64 years)has been increasing in recent years thanks to reductions in fertility.This shift in the

57、age distribution provides a time-bound opportunity for accelerated economic growth known as the“demographic dividend”.To maximize the potential benefits of a favourable age distribution,countries need to invest in the further development of their human capital by ensuring access to health care and q

58、uality education at all ages and by promoting opportunities for productive employment and decent work.More and more countries have begun to experience population decline The populations of 61 countries or areas are projected to decrease by 1 per cent or more between 2022 and 2050,owing to sustained

59、low levels of fertility and,in some cases,elevated rates of emigration.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Divisioniii Total fertility has fallen markedly in recent decades for many countries.Today,two-thirds of the gl

60、obal population lives in a country or area where fertility is below 2.1 births per woman,roughly the level required for zero growth in the long run for a population with low mortality.Among countries with at least half a million people,the largest relative reductions in population size until 2050,wi

61、th losses of 20 per cent or more,are expected to occur in Bulgaria,Latvia,Lithuania,Serbia and Ukraine.International migration is having important impacts on population trends for some countries In some parts of the world,international migration has become a major component of population change.For

62、high-income countries between 2000 and 2020,the contribution of international migration to population growth(net inflow of 80.5 million)exceeded the balance of births over deaths(66.2 million).Over the next few decades,migration will be the sole driver of population growth in high-income countries.B

63、y contrast,for the foreseeable future,population increase in low-income and lower-middle-income countries will continue to be driven by an excess of births over deaths.Between 2010 and 2021,40 countries or areas experienced a net inflow of more than 200,000 migrants each;in each of 17 of them,the ne

64、t inflow over this period exceeded 1 million people.For several of the top receiving countries,including Jordan,Lebanon and Trkiye,high levels of immigration in this period were driven mostly by refugee movements,in particular from Syrian Arab Republic.For 10 countries,the estimated net outflow of m

65、igrants exceeded 1 million over the period from 2010 through 2021.In many of these countries,the outflows were due to temporary labour movements,such as for Pakistan(net flow of-16.5 million),India(-3.5 million),Bangladesh(-2.9 million),Nepal(-1.6 million)and Sri Lanka(-1.0 million).In other countri

66、es,including Syrian Arab Republic(-4.6 million),Venezuela(Bolivarian Republic of)(-4.8 million)and Myanmar(-1.0 million),insecurity and conflict drove the outflow of migrants over this period.All countries,whether experiencing net inflows or outflows of migrants,should take steps to facilitate order

67、ly,safe,regular and responsible migration,in accordance with SDG target 10.7.The COVID-19 pandemic has affected all components of population change,including fertility,mortality and migration Global life expectancy at birth fell to 71.0 years in 2021,down from 72.8 in 2019,due mostly to the impact o

68、f the coronavirus disease(COVID-19)pandemic.The pandemics impact on life expectancy has varied across regions and countries.In Central and Southern Asia and in Latin America and the Caribbean,life expectancy at birth fell by almost three years between 2019 and 2021.By contrast,the combined populatio

69、n of Australia and New Zealand gained 1.2 years due to lower mortality risks during the pandemic for some causes of death.In some countries,the pandemic has been responsible for a significant reduction in life expectancy at birth.For Bolivia(Plurinational State of),Botswana,Lebanon,Mexico,Oman and t

70、he Russian Federation,estimates of life expectancy at birth declined by more than 4 years between 2019 and 2021.Available evidence about the effect of the COVID-19 pandemic on fertility levels remains mixed.In low-and middle-income countries,the availability of and the demand for contraception,as we

71、ll as reported numbers of unintended pregnancies and births,have remained relatively stable.In high-income countries,successive waves of the pandemic may have generated short-term fluctuations in numbers of pregnancies and births.The COVID-19 pandemic severely restricted all forms of human mobility,

72、including international migration.The magnitude of the pandemics impact on migration trends is difficult to ascertain due to data limitations.Population data provide critical information for use in development planning The quality of population estimates and projections hinges on the collection of r

73、eliable and timely demographic data,including through civil registration and vital statistics systems,population censuses,population registers and household surveys.The COVID-19 pandemic has affected many data collection operations worldwide.Countries and development partners should give priority to

74、 the ongoing 2020 round of national population censuses,as such data provide critical information to inform development planning and to assess progress towards the achievement of the SDGs.“Water for Peace”UN Photo/Harandane DickoWorld Population Prospects 2022:Summary of ResultsUnited Nations Depart

75、ment of Economic and Social Affairs,Population Division1IntroductionUnderstanding population trends and anticipating demographic change are crucial for national development planning and for implementing the 2030 Agenda for Sustainable Development.2 The 2030 Agenda emphasizes that people are at the c

76、entre of sustainable development,echoing the ideals set forth in the Programme of Action of the International Conference on Population and Development(ICPD)adopted in Cairo in 1994.Recent demographic trends are harbingers of future challenges to achieving the SDGs.For example,countries experiencing

77、rapid population growth,most of which are in sub-Saharan Africa,must provide schooling and health care to growing numbers of children,and ensure quality education and employment opportunities to increasing numbers of youth.Countries,where population growth has slowed or stopped,must prepare for an i

78、ncreasing proportion of older persons and,in some cases,decreasing population size.These and other challenges can be addressed in part by responding to future demographic trends and incorporating that information into policies and planning.World Population Prospects 2022 is the twenty-seventh editio

79、n of the official estimates and projections of the global population that have been published by the United Nations since 1951.They form a comprehensive set of demographic data to assess population trends at the global,regional and national levels.This report provides an overview of global populatio

80、n trends focusing on the period from 1950 to 2050 and presents a summary of key demographic prospects during the second half of the present century.The United Nations population estimates and projections are used in the calculation of many development indicators used by the United Nations system,inc

81、luding about one-quarter of the indicators used to monitor global progress towards the achievement of the SDGs.For the first time,the 2022 revision presents all demographic indicators and population estimates from 1950 and projections to 2100 by single age and sex for one-year intervals.The report i

82、s released amidst a global crisis caused by the coronavirus disease(COVID-19)pandemic.The world is faced with its continuing and profound impacts on the health of populations and on economies and societies with no clear end in sight.Empirical evidence of the impact of the pandemic on demographic phe

83、nomena remains incomplete due to gaps in the collection of demographic data and to time lags between data collection and dissemination.The full impact of the pandemic on national demographic trends may not be known for many years.The WHO-UN DESA Technical Advisory Group for COVID Mortality Assessmen

84、t3 was established to measure the excess deaths between 2020 and 2021.The report takes into account the estimates prepared by the advisory group as well as other robust information on the implications of the pandemic on mortality levels and trends through 2050,as well as on fertility and internation

85、al migration.The relationship between population and sustainable development should be considered within the context of climate change and other global environmental challenges that have a direct impact on sustainable development.The growth of the population itself may not be the direct cause of env

86、ironmental damage;it may nevertheless exacerbate the problem or accelerate the timing of its emergence,depending on the problem in question,the timeframe considered,the available technology and the demographic,social and economic context.Countries where fertility levels remain high should prepare to

87、 meet the needs of growing numbers of children and young people.Countries where a decline in fertility is creating an opportunity for a demographic dividend need to invest in human capital by ensuring access to health care and quality education at all ages and opportunities for productive employment

88、.Countries with ageing populations should take steps to adapt public programmes to the growing proportion of older persons.All countries should take steps to facilitate migration in line with target 10.7 of the SDGs and the Global Compact for Safe,Orderly and 2 A/RES/70/1.3 https:/who.int/data/techn

89、ical-advisory-group/covid-19-mortality-assessment/membership.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division2Regular Migration.4 Whereas all countries should take actions to tackle climate change and protect the environme

90、nt,more developed countrieswhose per capita consumption of material resources is generally the highestbear the greatest responsibility for implementing strategies to decouple human economic activity from environmental degradation.The report is organized into three parts.Part one describes the most l

91、ikely trends in population size,growth and age structure from 1950 to 2050.Part two discusses the demographic drivers of population changefertility,mortality and international migration and offers an assessment of the demographic impacts of the COVID-19 pandemic.Part three provides an overview of po

92、pulation trends until 2100 and their potential implications.4A/RES/73/195.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division3I.A century of world population trends:1950 to 2050Today,the worlds population is more than three t

93、imes larger than it was in the mid-twentieth century.The global human population will reach 8.0 billion in mid-November 2022 from an estimated 2.5 billion people in 1950,adding 1 billion people since 2010 and 2 billion since 1998.It took around 37 years since 1950 for human numbers to double,surpass

94、ing 5 billion inhabitants in 1987.Thereafter,it is estimated that more than 70 years will be required for the global population to double again,rising to over 10 billion by 2059(Part III).Over the one hundred years from 1950 to 2050,the world population was growing the fastest in the period 1962-196

95、5,when it was increasing on average by 2.1 per cent per year(figure I.1).Since then,the pace of population growth has slowed by more than half owing to reduced levels of fertility.In 2020,and for the first time since 1950,the rate of population growth fell below 1 per cent per year and it is project

96、ed to continue to slow in the next few decades and through the end of this century(Part III).The global population could grow to around 8.5 billion in 2030,and add 1.18 billion in the following two decades,reaching 9.7 billion in 2050.Figure I.1Global population size and annual growth rate:estimates

97、,1950-2022,and medium scenario with 95 per cent prediction intervals,2022-2050Given its reliance on assumptions at the country level about the two components of global population growthfertility and mortalitythe projection of the global population is inherently uncertain,and it typically becomes mor

98、e uncertain over time(box III.1).However,the size of the world population in the near future is relatively certain because the size and age structure of the population over the next few decades are largely the result of demographic processes that have already taken place in the recent past.In partic

99、ular,most of the women whose offspring will contribute to the population growth through 2050 are already alive.The prediction intervals shown in figure I.1 reflect the spread in the distribution of the simulated population trajectories and thus provide an assessment of the magnitude of the uncertain

100、ty inherent in the medium scenario.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division4The global population is still growing,albeit at a reduced rate.Some countries and regions continue to experience further population growt

101、h,while others have witnessed a stabilization or begun to decrease in population size.The worlds two most populous regions in 2022 were Eastern and South-Eastern Asia,with 2.3 billion people,representing 29 per cent of the global population,and Central and Southern Asia,with 2.1billion(26 per cent)(

102、figure I.2 and table I.1).China and India accounted for the largest populations in these regions,with more than 1.4 billion each in 2022.Figure I.2 Population estimates,1950-2022,and projections with 95 per cent prediction intervals,2022-2050,by regionThe population of Europe and Northern America co

103、mbined and that of sub-Saharan Africa were comparable in size in 2022,with more than 1.1 and 1.2 billion people respectively.However,these two regions have reached such population size as a result of very different growth trajectories since the mid-20th century.Whereas Europe and Northern America ha

104、ve been growing at an annual rate of less than 1 per cent since the mid-1960s,reaching a growth rate close to zero in 2020 and 2021,the annual growth rate of the population of sub-Saharan Africa peaked at 3 per cent in 1978 and remained above 2.8 per cent during the 1980s.Since the 1980s,sub-Saharan

105、 Africa has been the region with the fastest growing population.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division5Table I.1 Population of the world,SDG regions and selected groups of countries,2022,2030 and 2050 according t

106、o the medium scenarioPopulation(in millions)Region202220302050World7,9428,5129,687Sub-Saharan Africa1,1521,4012,094Northern Africa and Western Asia549617771Central and Southern Asia2,0752,2482,575Eastern and South-Eastern Asia2,3422,3722,317Latin America and the Caribbean658695749Australia/New Zeala

107、nd313438Oceania*141520Europe and Northern America1,1201,1291,125Least developed countries1,1121,3281,914Landlocked developing countries557664947Small island developing States 747987 *excluding Australia and New ZealandAlmost 44.8 million people lived in the two regions of Oceania in 2022.With 2.5 mi

108、llion inhabitants in 1950,the population of Oceania(excluding Australia and New Zealand)reached close to 13.6 million in 2022,while the population of Australia and New Zealand combined grew from 9.9 to 31.2 million from 1950 to 2022(table I.1).In the next three decades,the regions of the world will

109、experience different growth rates of their populations.Consequently,the regional distribution of the population in 2050 will significantly differ from that of today.Central and Southern Asia is expected to become the most populous region in the world by 2037 as the population of Eastern and South-Ea

110、stern Asia could start declining by the mid-2030s.Between 2022 and 2050,the population of sub-Saharan Africa is expected to almost double,surpassing 2 billion inhabitants by the late 2040s.With average fertility levels remaining close to 3 births per woman in 2050,sub-Saharan Africa is projected to

111、account for more than half of the growth of the worlds population between 2022 and 2050.In 2022,the size of the population in this region was growing at an annual rate of 2.5 per cent,the highest among all eight regions or more than three times the global average of 0.8 per cent per year.Europe and

112、Northern America is projected to reach its peak population size and to begin experiencing population decline in the late 2030s due to sustained low levels of fertility,which has been below 2 births per woman since the mid-1970s and,in some countries,high emigration rates.More than half of the projec

113、ted increase in the global population between 2022 and 2050 is expected to be concentrated in just eight countries:the Democratic Republic of the Congo,Egypt,Ethiopia,India,Nigeria,Pakistan,the Philippines and the United Republic of Tanzania.The populations of the Democratic Republic of the Congo an

114、d the United Republic of Tanzania are expected to grow rapidly,between 2 and 3 per cent per year over the 2022-2050 period.Disparate population growth rates among the worlds largest countries will change their ranking by size:for example,India is projected to surpass China as the worlds most populou

115、s country in 2023(figure I.3).World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division6Figure I.3Rankings of the worlds ten most populous countries,1990 and 2022,and medium scenario,2050(numbers in parentheses refer to total popul

116、ation in millions)Note:The figure depicts only those countries which are among the ten most populous countries in 1990,2022 or 2050.A blue arrow indicates that a country maintains the same rank,a yellow arrow indicates that a country increases in rank and a green arrow indicates that a countrys rank

117、ing is falling.The 10 highest ranking countries are shown in black.Other countries are shown in grey.The population of 61 countries or areas are projected to decrease by 1 per cent or more between 2022 and 2050.In countries with at least half a million population,the largest relative reductions in p

118、opulation size over that period,with losses of 20 per cent or more,are expected to take place in Bulgaria,Latvia,Lithuania,Serbia and Ukraine.China is expected to experience an absolute decline in its population as early as 2023.Globally,the world counts slightly more men(50.3 per cent)than women(49

119、.7 per cent)in 2022.This figure is projected to slowly invert over the course of the century.By 2050,it is expected that the number of women will equal the number of men.Historically,changes in a countrys population size have been a direct consequence of a process known as the demographic transition

120、 in which gradually decreasing levels of mortality and fertility lead to longer lives and lower average number of births per woman.The transition often unfolds in a series of stages,during which population growth first accelerates and then slows down.This transition is accompanied by changes in the

121、distribution of the population by age with a gradual increase in the share of older population.Due to the reduction of fertility in the intermediate stage of the transition,the relative size of successive birth cohorts begins to decline.Since the decline at younger ages is not immediately counterbal

122、anced by increases at older ages,the share of the population in the working ages grows temporarily relative to the combined shares at younger and older ages(Lee and Mason,2006).The growth of the share of the population at the working ages can provide an opportunity for accelerated economic growth an

123、d social development known World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division7as the“demographic dividend”.During this phase,overall dependency ratios fall,making more resources available to increase investments in education

124、,health,employment,social protection,pension schemes,etc.,thereby fostering short and medium-term economic growth and well-being.The population of working-age adults remains relatively large for several decades until eventually,population ageing generates a substantial increase in the percentage of

125、persons at older ages.In many countries in the advanced stages of the demographic transition,this demographic window of opportunity has already closed.Countries that are still at an early stage of the demographic transition,however,have an opportunity to maximize the benefits of the dividend by inve

126、sting in human capital formation.While the demographic circumstances underlying the dividend are conducive to rapid economic growth on a per capita basis,reaping its potential benefits requires significant investments in education and health,progress towards gender equality and the availability of g

127、ainful employment.Of the eight world regions,Eastern and South-Eastern Asia,Europe and Northern America,Australia and New Zealand,and Latin America and the Caribbean have the highest percentages of working-age population aged 25 to 64 years in 2022,accounting for 56,54,53 and 51 per cent of their to

128、tal population,respectively.However,due to advanced population ageing,the percentage of persons of working age has stabilized or has started to decrease in these regions,except for Latin America and the Caribbean where the share of the working-age population is projected to start declining in the ea

129、rly 2040s.In the other four world regions,the proportion of the working-age group will continue to increase for some time.In Central and Southern Asia and in Northern Africa and Western Asia,the population of working age is expected to start declining by 2045,whereas in Oceania(excluding Australia a

130、nd New Zealand)and sub-Saharan Africa,the working-age population will continue to increase until 2050.Worldwide,persons aged 65 years or over outnumbered children under age five for the first time in 2018.In 2022,there were 771 million people aged 65 years or over globally,3 times more than the size

131、 in 1980(258 million).The older population is projected to reach 994 million by 2030 and 1.6 billion by 2050.As a result,by 2050 there will be more than twice as many persons aged 65 or older than children under 5 globally,whereas the number of persons aged 65 years or over globally will be almost t

132、he same as the number of children under age 12.While in some countries the rapid growth of the older population results mainly from sustained high levels of fertility in the past,the continued reduction of premature mortality of successive generations is the main driver in other countries.The propor

133、tion of persons aged 65 or over is projected to increase globally between 2022 and 2050.At the world level in 2022,approximately 10 per cent of people are aged 65 or over(table I.2).The proportion of older persons in the world is projected to reach nearly 12 per cent in 2030 and 16 per cent in 2050.

134、Europe and Northern America had the largest proportion of older population in 2022,with almost 19 per cent aged 65 or over,followed by Australia and New Zealand(16.6 per cent).Both regions are continuing to age further.Projections indicate that by 2050 one in every four persons in Europe and Norther

135、n America could be aged 65 years or over.Populations in other regions are also projected to age significantly over the next several decades.For Latin America and the Caribbean,the share of the population aged 65 years or over could increase from 9 per cent in 2022 to 19 per cent in 2050.Similarly,th

136、e proportion aged 65 or over in Eastern and South-Eastern Asia is expected to double from around 13 per cent in 2022 to 26 per cent in 2050.Sub-Saharan Africa,which has the youngest age distribution of the eight SDG regions,is also projected to experience population ageing over the coming decades wi

137、th the percentage of the population aged 65 or over rising from three per cent in 2022 to almost five per cent in 2050.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division8Table I.2Percentage of population aged 65 years or ove

138、r for the world,SDG regions,and selected groups of countries,2022,2030 and 2050,according to the medium scenarioRegion202220302050World9.711.716.4Sub-Saharan Africa3.03.34.7Northern Africa and Western Asia5.57.012.5Central and Southern Asia6.48.113.4Eastern and South-Eastern Asia12.716.325.7Latin Am

139、erica and the Caribbean9.111.518.8Australia/New Zealand16.619.423.7Oceania*3.95.18.2Europe and Northern America18.722.026.9 Least developed countries3.64.16.1Landlocked developing countries(LLDC)3.64.15.8Small island developing States(SIDS)8.911.316.0 *excluding Australia and New ZealandBetween 2022

140、 and 2050,the older population is projected to grow at rates above 3 per cent per year in Northern Africa and Western Asia,sub-Saharan Africa,Oceania(excluding Australia and New Zealand)and Central and Southern Asia.Despite this rapid growth,these regions are projected to have relatively small propo

141、rtions of older people in 2050:13 per cent in Northern Africa and Western Asia and Central and Southern Asia and 5 and 8 per cent in sub-Saharan Africa and Oceania(excluding Australia and New Zealand),respectively.Countries with ageing populations should take steps to adapt public programmes to the

142、growing proportion of older persons,including sound social security and pension systems,the establishment of universal health care and long-term care systems.Globally,women outnumber men at older ages.In 2022,women comprised 55.7 per cent of persons aged 65 or older.Among regions,the share of women

143、in the population aged 65 or older is the lowest in Oceania(excluding Australia and New Zealand)(50.6 per cent)and the highest in Europe and Northern America(57.5 per cent)in 2022.With the ongoing progress in health and survival,allowing more men to reach older ages,the share of the women in the old

144、er population is projected to decrease to 54.5 per cent by 2050 at the global level.Similar patterns are expected to be observed across regions.In 2050,the share of women among the persons aged 65 or older is projected to range between 52 per cent in Northern Africa and Western Asia and 57 per cent

145、in Oceania(excluding Australia and New Zealand).The current age distribution of a population has a major impact on future population trends due to a phenomenon known as“population momentum”.The relative youthfulness of todays global population ensures that the number of women of reproductive age wil

146、l continue to increase for years and even decades.Nearly two-thirds of the anticipated increase in world population between 2022 and 2050 will be driven by the current age distribution of the global population(United Nations 2021a).Over a longer time period,however,the influence of todays age struct

147、ure will fade,and population growth will depend increasingly on the future course of mortality and,especially,fertility.Because of continued elevated levels of fertility in sub-Saharan Africa,the impact of momentum on the regions population growth between 2022 and 2050 is relatively less prominent(3

148、5 per cent)compared to the impact of fertility(43 per cent).World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division9In populations where fertility levels have been relatively low for several decades and the age distribution has b

149、een shifting toward older ages,the number of women in the reproductive age range may be decreasing.In such situations,the population momentum contributes to slower growth or,in extreme cases,to population decline.Due to its advanced process of demographic ageing,Europe,where fertility has been below

150、 the replacement level since the late 1970s,5 is the only region where momentum is expected to contribute to population decline between 2022 and 2050(minus 7 per cent).Linkages between population trends and selected Sustainable Development Goals(SDGs)A path towards a more sustainable future requires

151、 demographic foresight,which involves anticipating the nature and consequences of major population shifts before and while they occur and adopting forward-looking and proactive planning guided by such analysis.The growing concentration of population growth in the less developed regions can pose chal

152、lenges to the ability of countries to attain progress in development.Rapid growth of a countrys population can exacerbate the challenge of eradicating poverty(SDG 1),potentially trapping communities in a vicious cycle:while economic growth may struggle to keep pace with population growth,poverty can

153、 deprive individuals of opportunities and choices,limiting their ability to control their fertility,perpetuating high levels of childbearing often starting early in life and ensuring the continued rapid growth of the population.Reducing poverty in the context of rapid population growth remains a for

154、midable challenge.In many cases,even though poverty reduction strategies may lift large numbers of people out of poverty,the proportion of the population living below the poverty line may be stagnant or even increase.The population in many countries in sub-Saharan Africa is projected to double betwe

155、en 2022 and 2050,putting additional pressure on already strained resources and challenging policies aimed to reduce poverty and inequalities.For example,Angola has experienced population growth rates above 3 per cent per year since the early 1970s due to the combined effect of persistent high fertil

156、ity levels and remarkable reductions in infant and child mortality,in particular during the past two decades.In 2018,around half of the population in that country was living in extreme poverty(figure I.4).From 2008 to 2018,the increase in the number of people living in extreme poverty(109 per cent)o

157、utpaced the growth of the total population(44 per cent).During the first decade of the current millennium,Uganda made remarkable progress in reducing extreme poverty in a context of rapid population growth.Since 2010,however,the number of people living below the international poverty line has increa

158、sed more rapidly than the entire population.In Madagascar,the population has been growing at a rate of about 3 per cent per year for several decades.The country remains one of the poorest countries in the world,with more than 70 per cent of its people living below the international poverty line.5 Re

159、placement-level fertility refers to the level of childbearing at which each generation exactly replaces the previous one in terms of size.If fertilityremains below this level over the long run,the population will eventually decline in size(assuming that immigration levels will be insufficient tocomp

160、ensate for the decline).For populations at late stages of the demographic transition,the replacement level of fertility is approximated by atotal fertility rate of 2.1 births per woman.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Populati

161、on Division10Figure I.4Population growth rate,2015-2020,by the proportion of the population living below the international poverty line,2003-2021Source:Based on the most recent data available for the period 2003-2021,SDG Indicators Database,available at https:/unstats.un.org/sdgs/dataportal/database

162、/.Accessed on 2 June 2022.Note:SDG indicator 1.1.1 is the proportion of the population living below the international poverty line,which the World Bank has defined as a per capita income of U.S.dollars 1.90 per day in terms of purchasing power parity(PPP).Providing inclusive and equitable quality ed

163、ucation at all levels is critical for achieving the Sustainable Development Goals as access to life-long learning opportunities will help people,especially those in vulnerable situations,to acquire the knowledge and skills needed to exploit opportunities and to participate fully in society.6 Expandi

164、ng educational opportunities and ensuring quality education for all can be particularly challenging for low-and lower-middle income countries with growing cohorts of children and youth.In sub-Saharan Africa,the completion rate of upper secondary education7 increased only 3.4percentage points,from 23

165、.3 per cent to 26.7 per cent,during the past decade,leaving that region furthest behind.Mali and Niger are among the countries with the highest percentages of youth of secondary school age and the lowest upper secondary education completion rates(figure I.5).The population in this age group has been

166、 growing rapidly in both countries,close to or above 2.5 per cent per year since the mid-2000s and is expected to continue growing relatively fast for the next two decades.According to the latest data available in 2020,in Mali,only about 1 in 8 young people of secondary school age completed upper se

167、condary education,and only 33 per cent completed lower secondary education.In Niger,completion rates are even lower:10 per cent for lower secondary education and only 2.5 per cent for the upper secondary level in 2020.6 A/RES/70/1,para 25.7 The completion rates for primary education,lower secondary

168、education and upper secondary education(SDG indicator 4.1.2)measure theimplementation of SDG target 4.1,which,seeks to ensure that,by 2030,all girls and boys complete free,equitable and quality primary andsecondary education leading to relevant and effective learning outcomes.World Population Prospe

169、cts 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division11Among the lower-middle-income countries,Kenya had a completion rate for upper secondary education of about 42 per cent in 2020,significantly higher than in most countries in the region with simil

170、ar proportions of youth aged 12 to 17.However,access to quality education in Kenya is still challenged by various factors,such as inadequate infrastructure,shortage of teachers and underfunding.Figure I.5Proportion of youth aged 12 to 17 years in 2021,by the upper secondary education completion rate

171、,2006-2020Source:Based on the most recent data available for the period 2006-2020,SDG Indicators Database;available at https:/unstats.un.org/sdgs/dataportal/database/.Accessed on 2 June 2022.Note:A completion rate at or near 100 per cent indicates that all or most children and adolescents have compl

172、eted a level of education by the time they are 3 to 5 years older than the official age of entry into the last grade of that level of education.A low completion rate indicates low or delayed entry into a given level of education,high drop-out,high repetition,late completion or a combination of these

173、 factors.The population aged 12 to 17 years is a rough estimate of the population of typical secondary education ages,according to the International Standard Classification of Education(ISCED,2011).The slow progress in expanding education opportunities in low-and lower-middle-income countries has be

174、en further reduced by the COVID-19 pandemic.The COVID-19 pandemic has exacerbated longstanding inequalities in access to quality education,negatively affecting the learning and well-being of millions of children and youth worldwide(UNESCO 2021,2022).As a result,past increases in school completion ra

175、tes may slow or even reverse depending on the duration of full or partial school closures and other factors affecting the health and well-being of children,their families,and educators.Photo areaPhoto title“A woman sits by the side of the road outside of Skopje,FYR Macedonia.Poverty and unemployment

176、 are high in the country”Photo:Tomislav Georgiev/World BankWorld Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division13II.Trends in fertility,mortality and international migrationTrends in population size and age structure are shape

177、d mostly by levels of fertility and mortality,which have declined almost universally around the globe.In some countries,international migration also has become an important determinant of population change.The fertility level,or the average number of births per woman over a lifetime,has fallen marke

178、dly over recent decades in many countries.Two-thirds of all people globally live in a country or area where fertility is below 2.1 births per woman,which is roughly the level required for populations with low mortality to stabilize in the long run.In 2021,the average global fertility rate stood at 2

179、.3 births per woman,falling from about 5 births per woman in the mid-twentieth century(figure II.1,Panel A).According to the assumptions about future fertility made in the United Nations projections(box III.1),by 2050,the average global fertility rate is expected to have declined to 2.1.To be more p

180、recise,with a probability of 95 per cent,global total fertility in 2050 is expected to lie between 1.88 and 2.42 births per woman(figure II.1,shaded area around the projected trend).Figure II.1Global total fertility rate(Panel A)and number of births(Panel B):estimates,1950-2021,and medium scenario w

181、ith 95 per cent prediction intervals,2022-2050Despite the continuing decline in the average number of births per woman,the total annual number of births has remained stable at around 140 million since the late 1980s due to the youthful age distribution of the global population.The number of births h

182、as approached 140 million per year in the late 1980s,when the large cohorts of the earlier“baby boom”of the 1950s and 1960s were having their children(figure II.1,Panel B).In 2021,134 million babies were born worldwide.In the future,the number of newborns is expected to slightly increase to reach 13

183、8 million annually between 2040 and 2045,despite the continuous decline in the average number of births per woman.Because uncertainty around the number of births is cumulative i.e.,each birth cohort will potentially become the parents of future generationsthe plausible or likely range for future num

184、bers of births is relatively wide:with a probability of 95 per cent,the size of the global birth cohort in 2050 will lie between 118 and 155 million.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division14In 2021,most births wor

185、ldwide occurred in the two most populous regionsCentral and Southern Asia(28 per cent of global births)and Eastern and South-Eastern Asia(18 per cent)and in sub-Saharan Africa(29 per cent),the region with the highest fertility level.There is a wide variation in fertility levels across regions and co

186、untries(figure II.2,table II.1).In addition to sub-Saharan Africa(4.6 births per woman),fertility remained above the worlds average in 2021 in Oceania excluding Australia and New Zealand(3.1),Northern Africa and Western Asia(2.8),and Central and Southern Asia(2.3).Figure II.2Total fertility rate:est

187、imates,1950-2021,and medium scenario,2022-2050Elsewhere,the total fertility rate has fallen below 2 births per women and has been fluctuating in recent years,typically between 1.5 and 2 births per woman.Today,such countries are home to two thirds of the worlds population.Most countries in Europe and

188、 Northern America,as well as Australia and New Zealand,have experienced persistent low levels of fertility since the late 1970s,with several countries falling at least temporarily below 1.4 births per woman.In some of these countries,fertility,after increasing in recent decades,has slightly declined

189、 in the most recent years.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division15Table II.1Total fertility for the world,SDG regions and selected groups of countries,1990,2021 and 2050 according to the medium scenarioRegionAver

190、age number of births per woman199020212050World3.32.32.1Sub-Saharan Africa6.34.63.0Northern Africa and Western Asia4.42.82.2Central and Southern Asia4.32.31.9Eastern and South-Eastern Asia2.61.51.6Latin America and the Caribbean3.31.91.7Australia/New Zealand1.91.61.7Oceania*4.73.12.4Europe and North

191、ern America1.81.51.6 Least developed countries6.04.02.8Landlocked developing countries 5.74.02.7Small island developing States 3.32.32.0 *excluding Australia and New ZealandStarting in the 1960s,fertility levels in Eastern and South-Eastern Asia declined more rapidly compared to Europe and other reg

192、ions where the decline happened earlier,owing both to the rapid pace of socioeconomic development and to the effectiveness of state-sponsored family planning programmes in supporting changing patterns of childbearing.Since 2018,Latin America and the Caribbean joined the list of regions where fertili

193、ty has fallen below 2 births per woman over a lifetime.In 2021,about 13.3 million babiesor 10 per cent of the global number of birthswere born to young mothers under the age of 20 worldwide,half of them in sub-Saharan Africa.Levels of adolescent childbearing have fallen most notably in Northern Afri

194、ca and Western Asia since the late 1970s and in Central and Southern Asia since the late 1980s.In sub-Saharan Africa,the birth rate among adolescents was estimated to have fallen recently;however,it remains the highest among all regions,at 101 births per 1,000 women aged 15 to 19 in 2021(figure II.3

195、).Latin America and the Caribbean was the region with the second highest level of adolescent fertility,at 53 births per 1,000 women aged 15 to 19.In 2021,the contribution of adolescent fertility to the total fertility was the highest in Latin America and the Caribbean with 14 per centa level about 3

196、0 per cent higher than in sub-Saharan Africa.Early pregnancy and motherhood can have adverse health and social consequences both for the young mothers and for the children they bear.In Latin America and the Caribbean and sub-Saharan Africa,most governments considered adolescent fertility a major con

197、cern and have adopted policy measures to improve the sexual and reproductive health of adolescents(United Nations,2021c).World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division16Figure II.3Adolescent birth rate,2021Source:World P

198、opulation Prospects 2022.The designations employed and the presentation of material on this map do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country,territory,city or area or of its authorities,or concer

199、ning the delimitation of its frontiers or boundaries.The dotted line represents approximately the Line of Control in Jammu and Kashmir agreed upon by India and Pakistan.The final status of Jammu and Kashmir has not yet been agreed upon by the parties.The final boundary between the Republic of Sudan

200、and the Republic of South Sudan has not yet been determined.A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands(Malvinas).Global life expectancy at birth reached 72.8 years in 2019,an impr

201、ovement of almost 9 years since 1990.According to current projections,further improvements in survival are expected to result in an average length of life globally of around 77.2 years in 2050.Because the global population is growing and also ageing rapidly(part I),the number of deaths worldwide is

202、expected to increase over the next decades,from 67 million in 2022 to 92 million in 2050(figure II.4,Panel B).While considerable progress has been made in closing the difference in life expectancy at birth between countries,the gaps remain wide.In 2021,life expectancy in the least developed countrie

203、s lagged 7.0 years behind the global average,due largely to persistently high levels of child and maternal mortality and,in some countries,to violence and conflicts or the continuing impact of the HIV epidemic.Progress in life expectancy at birth has slowed down in 2020 and 2021 due to the impact of

204、 the COVID-19 pandemic(box II.1 and figure II.4,Panel A).Available evidence suggests that in some countries of Europe and Northern America,progress in life expectancy was already slowing or stalling even before the outbreak of the pandemic.In Canada,the United Kingdom and the United States,for examp

205、le,vital statistics point to levels of life expectancy for recent years that are lower than what was previously projected based on the historical trajectory of improvement in survival in each country.The stalling life expectancy in the United States,for example,was mostly attributable to the stagnat

206、ing decline in cardiovascular disease mortality(Mehta,Abrams and Myrskyl,2020).World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division17Figure II.4Global life expectancy at birth(Panel A)and number of deaths(Panel B):estimates,19

207、50-2021,and medium scenario with 95 per cent prediction intervals,2022-2050In 2021,the disparity between the country with the highest and the country with lowest life expectancy at birth stood at 33.4.Among the countries with a population of at least half million in 2022,life expectancy at birth rea

208、ched close to 85 years or above years in 2021 in Australia,the Hong Kong and Macao special administrative regions of China,and Japan.In contrast,life expectancy at birth is the lowest in Central African Republic,Chad,Lesotho and Nigeria with levels below 54 years in 2021.In the coming decades,furthe

209、r increases in survival are expected to narrow but not to eliminate differences in life expectancy across countries and regions(table II.2).By 2050,life expectancy at birth is projected to reach 77.2 years worldwide,with a gap of 31.8 years remaining between the countries with the lowest and the hig

210、hest values.As countries complete the demographic transition and reach historically low levels of mortality,further reductions in death rates become more difficult to achieve and the rise in life expectancy slows down,prompting a trend towards convergence between countries and regions over the long-

211、term(Part III).In some regions,life expectancy at birth actually declined during the late 1980s and 1990s due primarily to the HIV epidemic in sub-Saharan Africa and the health crisis in Eastern Europe following the dissolution of the Soviet Union.These setbacks have long-lasting effects on life exp

212、ectancy at birth.Countries in sub-Saharan Africa experienced only limited progress in survival during the period 1980-2000.The slow recovery in life expectancy at birth in the countries of the former Soviet Union explains the large and continuing differences across European countries.In 2021,life ex

213、pectancy at birth ranged from less than 70 years in the Republic of Moldova and the Russian Federation to 84 years in Switzerland.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division18Figure II.5Life expectancy at birth:estima

214、tes,1950-2021,and medium scenario,2022-2050,by regionNote:The figure depicts values for the“period”life expectancy,which shows the average age a newborn would live to if current death rates continued for their whole life.These estimates do not predict actual lifespans.That is,a life expectancy in 20

215、20 lower than in 2019,which may be due to the COVID-19 pandemic,does not mean that a newborn in 2020 is expected to have a shorter life than one born in 2019.Gender inequalities across the world make women and girls more vulnerable to poor health,often putting them at higher risks of death,including

216、 from a maternal cause.At the global level,however,women live on average longer than men(table II.2).Higher male mortality has been associated with behavioural factors and genetic differences(Austad,2006).In 2021,life expectancy at birth for women exceeded that for men by 5.4 years globally,with fem

217、ale and male life expectancies standing at 73.8 and 68.4,respectively.This female survival advantage is observed in virtually all regions and countries of the world.The female advantage in life expectancy at birth ranged from 7 years in Latin America and the Caribbean to 2.9 years in Australia and N

218、ew Zealand.The COVID-19 pandemic contributed to widening the gap in life expectancy at birth between sexes.In 2019,this gap reached 5.2 years.In the last three decades,the sex gap in life expectancy at birth shrank in some regions(Australia and New Zealand,Europe and Northern America),but increased

219、in others(Central and Southern Asia,and Eastern and South-Eastern Asia)(United Nations,2020a).In sub-Saharan Africa,the rise in the sex differential of life expectancy at birth was interrupted in the late 1990s due to the disproportionate impact of the HIV/AIDS epidemic on female mortality in that r

220、egion,which had its maximum effect on mortality rates in the mid-2000s.The COVID-19 pandemic contributed to a slight increase in the gap in life expectancy at birth between the sexes.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population

221、 Division19Table II.2Life expectancy at birth by sex for the world,SDG regions,and selected groups of countries,1990,2021 and 2050RegionLife expectancy at birth(years)199020212050MalesFemalesBoth sexesMalesFemalesBoth sexesMalesFemalesBoth sexesWorld61.566.564.068.473.871.074.879.877.2Sub-Saharan Af

222、rica47.351.249.257.861.659.764.369.166.7Northern Africa and Western Asia61.767.064.369.774.872.176.080.878.3Central and Southern Asia58.159.958.965.969.667.774.979.477.1Eastern and South-Eastern Asia65.670.768.173.679.676.579.484.181.7Latin America and the Caribbean64.670.967.768.875.872.278.183.180

223、.6Australia/New Zealand73.779.876.882.785.684.285.488.687.0Oceania*60.365.562.564.670.167.168.474.971.6Europe and Northern America69.777.473.673.980.477.281.686.183.8Least developed countries48.751.650.161.766.564.167.873.570.6Landlocked developing Countries 49.053.551.261.066.563.767.473.470.3Small

224、 island developing States 63.467.965.668.073.970.874.180.077.0*excluding Australia and New ZealandA large portion of the gap between countries with the lowest and highest levels of life expectancy at birth is attributable to disparities in the under-five mortality rate,which represents the probabili

225、ty of dying between birth and age 5.Progress in reducing under-five mortality has been substantial and far-reaching in recent years,yet gaps remain.Globally,the under-five mortality rate fell from 92.8 deaths per 1,000 live births in 1990 to 37.1 in 2021.Still,a child born in sub-Saharan Africa in 2

226、021 is 20 times as likely to die before his or her fifth birthday as a child born in Australia and New Zealand.Although the HIV/AIDS epidemic continues to be a major public health concern,HIV-related mortality among adults appears to have reached a peak over the past decade in most countries that ha

227、ve been highly affected by the epidemic,thanks mostly to the increasing availability of antiretroviral treatments(ART).Nevertheless,in countries where HIV prevalence has been high,the impact of the epidemic in terms of morbidity,mortality and slower population growth continues to be evident.Thus,in

228、Southern Africa,the sub-region with the highest prevalence of the disease,life expectancy at birth fell from 63.1 years in 1990 to 53.1 years in 2005(before the introduction of ART).Life expectancy in Southern Africa had returned to its 1990 level by 2015 and increased further to 65.5 in 2019,repres

229、enting a loss of two decades of potential improvements in survival rates.The COVID-19 pandemic contributed to removing the gains in life expectancy recorded in Southern Africa over the past decades with life expectancy at birth declining to 61.8 years in 2021.Life expectancy at age 65 reflects the a

230、verage number of additional years of life a 65-year-old person would live,according to the prevailing mortality conditions.Before the outbreak of the COVID-19 pandemic,in 2019,people who had already survived to age 65,could expect to live on average an additional 17.5 years worldwide,6.2 years longe

231、r than a person of the same age in the early 1950s.In 2019,women aged 65years could expect to live an additional 18.8 years and 65-year-old men an additional 15.9 years.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division20In

232、2021,Australia,Hong Kong SAR(China),Macao SAR(China),and Japan had the highest life expectancies at birth(about 85 years)and at age 65(21.6 and over years)among the countries and areas with at least half a million population.A decrease in mortality from non-communicable diseases,such as cardiovascul

233、ar disease,diabetes,cancer,and chronic respiratory disease and other age-related chronic conditions are expected to continue contributing to the extension of life.In 2050,a 65-year-old person is expected to live on average an additional 19.8 years in 2050 globally.As is the case for many causes of d

234、eath,COVID-19 is responsible for many more deaths among older persons than among younger persons(WHO,2022).At the individual level,older people have a higher risk of serious illness and higher case fatality rates8 than people in younger age groups.In addition,environmental and societal factors accou

235、nt for substantial variation across countries in old-age COVID-19 mortality;among these are the prevalence of co-morbidities in their national populations,the presence of robust old-age social protection systems,and the capacity of health systems to protect those at increased risk once the outbreak

236、unfolded.The living arrangements of older persons in congregate settings has emerged as another factor of increased risk of contracting and dying from COVID-19,as it increases the efficiency of viral spread(Comas-Herrera and others,2020).Based on the latest available estimates of the effect of the C

237、OVID-19 pandemic on mortality(box II.1),the global life expectancy at age 65 lost 1.2 years between 2019 and 2021,or more than 71 per cent of the total decline in life expectancy at birth.With the exception of Australia and New Zealand,all regions of the world experienced a decline in the average nu

238、mber of years a 65-year-old person could expect to live.The decline was the strongest in Central and Southern Asia(-2.3 years)and Latin America and the Caribbean(-1.5 years).In some parts of the world,international migration has become a major component of population change.During the period 1980-20

239、00,population growth in high-income countries was mainly due to natural increase(104 million),that is,the difference between the total number of births and deaths,which was more than twice the contribution of net international migration to population growth(44 million),that is,the difference between

240、 immigration and emigration.For high-income countries between 2000 and 2020,the contribution of international migration to population growth(net inflow of 80.5 million)exceeded the balance of births over deaths(66.2 million).Over the next few decades,migration will be the sole driver of population g

241、rowth in high-income countries,as the number of deaths will progressively exceed the number of births(figure II.6).By contrast,for the foreseeable future,population increase in low-income and lower-middle-income countries will continue to be driven by an excess of births over deaths.At the country l

242、evel,large variations in the relative contribution of natural change and net migration to overall population change are observed.Between 2010 and 2021,40 countries or areas have experienced a net inflow of more than 200,000migrants;in 17 of those,the total net inflow exceeded 1 million people.In 202

243、0,Trkiye hosted the largest number of refugees and asylum seekers worldwide(nearly 4 million),followed by Jordan(3 million),the State of Palestine(2 million)and Colombia(1.8 million).Other major destination countries of refugees,asylum seekers or other persons displaced abroad were Germany,Lebanon,P

244、akistan,Sudan,Uganda and the United States of America(United Nations,2020b).8 The case fatality rate refers to the proportion of people who died from COVID-19 among all persons infected with COVID-19 during a certain period of time.World Population Prospects 2022:Summary of ResultsUnited Nations Dep

245、artment of Economic and Social Affairs,Population Division21Box II.1The impact of the COVID-19 pandemic on fertility,mortality and international migrationThe evidence of the full demographic impact of the pandemic remains incomplete,owing both to gaps in the collection of demographic data and to tim

246、e lags between data collection and dissemination.Despite these challenges,World Population Prospects 2022 accounts for the impact of the COVID-19 pandemic on population and demographic estimates,using the latest available evidence.The available evidence of the effect of the COVID-19 pandemic on fert

247、ility remains mixed.The pandemic could potentially influence the number of births per woman through various channels,such as postponement of childbearing in the face of the uncertainty regarding the disease and its economic impacts,disruptions in marriage patterns and family formation,and disruption

248、s in the availability and access to sexual and reproductive health-care services,including family planning.The available evidence on the impact of the pandemic on fertility also suggests differences by level of income.The latest studies in low-and middle-income countries have shown little evidence o

249、f a change in the number of unintended pregnancies and births.In these countries,contraceptive availability and demand have remained relatively stable(United Nations,2021d).In high-income countries,the COVID-19 pandemic acted as a temporary interruption rather than a permanent change in long-term tr

250、ends.The successive waves of the pandemic may have produced temporary reductions in the numbers of pregnancies and births,without affecting long-term trends in countries with low fertility.Given this evidence,no additional impact of the COVID-19 pandemic was included in the fertility estimates of Wo

251、rld Population Prospects 2022 other than those already reflected in available national data.The Population Division of the United Nations Department of Economic and Social Affairs(UN DESA)collaborated with the World Health Organization(WHO)to develop estimates of numbers of deaths attributable to th

252、e direct and indirect impacts of the pandemic.The excess mortality associated with the pandemic is estimated to have reached 14.9 million for the period between 1 January 2020 and 31 December 2021a figure almost 3 times the officially reported numbers of deaths.9 The excess mortality was calculated

253、as the difference between the number of deaths that have occurred and the number of deaths that would be expected to occur in the absence of the pandemic based on estimates from previous years.Deaths directly associated with COVID-19 are deaths due to the disease.Indirect deaths attributed to the pa

254、ndemic are those that occurred due to the impact of the pandemic on health systems and on the society at large and include deaths attributable to health conditions for which people were unable to access prevention or treatment due to overburdened health systems.The excess mortality estimates are als

255、o accounting for deaths that may have been averted during the pandemic due to lower mortality risks,such as deaths due to seasonal influenza,traffic accidents or occupational injuries.The estimates of mortality due to COVID-19 indicate that the global death toll was higher for men than for women and

256、 higher among older adults than for younger persons.It is estimated that life expectancy at birth fell to 71.0 years in 2021 due to the impact of the COVID-19 pandemic.Globally,the COVID-19 pandemic contributed to a loss of 1.7 years of life expectancy at birth between 2019 and 2021.These estimates

257、are derived through an innovative methodology which produces comparable mortality estimates even in a context where data are incomplete or unavailable(Knutson and others,2022;WHO,2022).The excess mortality estimates are available only for 2020.After 2021,World Population Prospects 2022 takes differe

258、nt approaches in terms of recovery from the effects of the pandemic.Depending on the availability of recent mortality data by country and the prevalence of COVID-19 vaccination(i.e.,at least one injection),life expectancy at birth was assumed to return to pre-pandemic levels and trends in 2022 for c

259、ountries with high vaccination prevalence or with data supporting such patterns.For all other countries with low vaccination prevalence or without additional data,World Population Prospects 2022 assumes a return to pre-pandemic mortality levels and trends with a time lag of 1 to 3 years.9 https:/who

260、.int/news/item/05-05-2022-14.9-million-excess-deaths-were-associated-with-the-covid-19-pandemic-in-2020-and-2021.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division22 Box continuedAvailable data indicate that there was no con

261、vincing evidence of a reversal in child mortality gains,as it had been feared early during the COVID-19 pandemic.However,it is worth noting that indirect impacts of the pandemic on child mortality could take time to unfold.The impact of factors such as interruptions in routine childhood immunization

262、 and nutritional programmes and other pandemic conditions such as increased food insecurity and loss in household income may be observed in the coming years,as they may take some time to be realized(UNICEF and others,2021).The COVID-19 pandemic severely restricted all forms of human mobility.The clo

263、sing of national borders and disruptions of international travel affected or canceled plans of people to move to another country.Hundreds of thousands of migrants were stranded,unable to return to their country,while reduced job opportunities and school closures forced many others to return to their

264、 home countries earlier than planned.While it remains difficult to assess the full extent of the pandemics impact on migration trends,World Population Prospects 2022 assumed a halving of net migration during 2020 and 2021.It is estimated that ten countries experienced a net outflow of more than 1 mi

265、llion migrants between 2010 and 2021.In many of these countries,these outflows were due to temporary labour movements,such as for Pakistan(net outflow of-16.5 million during 2010-2021),India(-3.5 million),Bangladesh(-2.9 million),Nepal(-1.6 million)and Sri Lanka(-1 million).In other countries,includ

266、ing Syrian Arab Republic(-4.6 million),Venezuela(Bolivarian Republic of)(-4.8 million),and Myanmar(-1 million),insecurity and conflicts have driven the net outflow of migrants over the decade.The conflict in Ukraine has forced people to flee their homes seeking safety,protection and assistance.By th

267、e end of May 2022,the conflict had displaced some 13 million persons,including 6.8 million refugees who have fled Ukraine,mostly crossing into Poland and other neighbouring countries(Office of the United Nations High Commissioner for Refugees,2022).World Population Prospects 2022:Summary of ResultsU

268、nited Nations Department of Economic and Social Affairs,Population Division23Figure II.6Contributions to total population change of the balance of births over deaths and of immigration over emigration,by income group,from 1950-1960 to 2040-2050World Population Prospects 2022:Summary of ResultsUnited

269、 Nations Department of Economic and Social Affairs,Population Division24Box II.2Data sources used in World Population Prospects 2022The United Nations publishes population estimates and projections for 237 countries or areas,comprising the entire population of the world.For the 236 countries or area

270、s that had at least 1,000 inhabitants in 2021,the data set contains complete time series of population size by age and sex and of the components of population changefertility,mortality and international migrationfrom 1950 until 2100.The quality of population estimates and projections hinges on the a

271、vailability of reliable and timely demographic data,including data collected through civil registration and vital statistics(CRVS)systems,population censuses,population registers and household surveys.Recent and historical data on the size of the population and its composition by age and sex,as well

272、 as information on levels and patterns of the components of population change,are used for the preparation of population estimates for each country or area.Recent population counts are critical for obtaining accurate estimates of population size and its composition by age and sex(Spoorenberg,2020).T

273、he principal data source for this purpose is the population census.Most countries conduct a census approximately once per decade.The COVID-19 pandemic disrupted the planning and conduct of population censuses from 2020 onwards and has impaired the functioning of registration and reporting systems in

274、 many countries.A recent survey indicated that the pandemic had a negative impact on the preparation,fieldwork or collection phases of the census in some 75 per cent of the 111 countries that responded(United Nations Statistics Division 2021).Some countries had used administrative registers as sourc

275、es of census data.It is important to assess the impacts of the pandemic on the timely production of complete and reliable population data and to learn from these experiences how to build more efficient and resilient data systems.For the estimation period between 1950 and 2022,data from 1,758 censuse

276、s were considered in the present evaluation.In some countries,population registers based on administrative data systems provide the necessary information.Population data from censuses or registers referring to 2015 or later were available for 152 countries or areas,representing 64 per cent of the 23

277、7 countries or areas included in this analysis.For 74 countries or areas,the most recent available population count was from the period 2005-2014.For the remaining 11 countries or areas,the most recent available census data were from before 2005.In addition,information on births and deaths from civi

278、l registration and vital statistics systems for 169 countries,and demographic indicators from 2,890 surveys,were considered in the present evaluation.A key task in preparing estimates and projections of the world population is to ensure that,for each country,past,current and future trends in fertili

279、ty,mortality and international migration are consistent with changes in the size of the population and its distribution by age and sex.Various techniques are used to identify the most likely trends in fertility,mortality and international migration.For countries where no or only minimal data are ava

280、ilable,demographic and statistical models are used to estimate levels of fertility,mortality and migration.Times series of population estimates,and of the components of population change,are critical inputs for the creation of population projections,as they provide a starting point for the projected

281、 future trends.Civil registration and vital statistics systems are the preferred source of information for computing statistics on levels and trends in the fertility and mortality of a population,and for tracking changes in the size of a population and in its distribution by age and sex between cens

282、uses.In addition to being a source of essential population statistics,the universal registration of births and deaths also helps World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division25 Box continuedto ensure access to legal ide

283、ntity for all persons,as called for in SDG target 16.9 on“legal identity for all,including birth registration”.Although complete vital statistics are essential for demographic accounting,many countries lack such statistics.Among 233 countries or areas,10 only 73 per cent of the countries,territories

284、 and areas register at least 90 per cent of births.Furthermore,for death registration,only 68 per cent of the countries,territories and areas register at least 90 per cent of deaths.Demographic data are essential for development planning and for assessing progress towards the achievement of the Goal

285、s and targets of the 2030 Agenda for Sustainable Development.The United Nations population estimates and projections are used for the global monitoring of around one quarter of the 231 SDG indicators.Data from the World Population Prospects are used to compute national-level estimates for a subset o

286、f these indicators and,more broadly,to derive regional aggregates using a consistent set of population weights.Assessing statistical capacity gaps between countries to collect,generate,analyse and disseminate demographic data,and strengthening national capacities where most needed,are crucial factor

287、s both for the implementation of national planning and for SDG reporting.10 https:/unstats.un.org/unsd/demographic-social/crvs/.Photo areaPhoto title“Children in primary school on the first day of classes in the new school year”Photo:Genti Shkullaku/World BankWorld Population Prospects 2022:Summary

288、of ResultsUnited Nations Department of Economic and Social Affairs,Population Division27III.Long-range population projections to 2100Long-range population projections are highly uncertain,especially for high-fertility countries still in the early stages of the demographic transition.As mentioned in

289、Part I,there is a probability of 95 per cent that the size of the global population will lie between 9.4 and 10.0 billion in 2050 and between 8.9 and 12.4 billion in 2100(box III.1).Thus,the size of the worlds population is almost certain to rise over the next several decades,as is the degree of unc

290、ertainty associated with these projections.Later in the century,there is about 50 per cent chance that the worlds population will peakthat its size will stabilize or begin to decreasebefore 2100.As fertility will be the most important determinant of global population trends in the coming decades,unc

291、ertainty around the number of children to be born in populous,high-fertility countries is a major source of the uncertainty in global population projections.Because of the momentum of growth embedded in current age structures,reductions in fertility over the next several years will have only a limit

292、ed effect on the growth of the world population between now and 2050.However,a fertility decline in the near term can have important consequences for growth in the last decades of the century as the impact of fertility decline on population size cumulates from one generation to the next.Increasing u

293、ncertainty at dates farther into the future is reflected in a widening band of prediction intervals for projections of the number of births and of the total population size(figure III.1).It is projected that 136 million babies will be born worldwide in 2050,with upper and lower bounds of the predict

294、ion interval indicating that the observed number of births in that year could plausibly deviate from the median trajectory by up to 19 millionthus,an uncertainty range of more than one fourth of the median value(27 per cent).Over the following five decades,the number of births is projected to decrea

295、se by 24 million globally,reaching 111 million in 2100.At that point,the uncertainty range widens to nine tenths of the median value(90 per cent)as the prediction interval extends from 77 to 178 million.Figure III.1Global population size and total number of births and deaths,estimates(1950-2022)and

296、medium scenario with 95 per cent prediction intervals,2022-2100World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division28For both fertility and mortality,the uncertainty of projected levels and trends was assessed using a predicti

297、ve model derived from a probabilistic analysis of the observed variability of changes over time in the past.In each case,the most likely future course of fertility based on several thousand statistical simulations was taken as the most likely future trend.International migration is the component of

298、population change that is the most difficult to project.Given the sparsity and/or incompleteness of data on past trends as well as the potentially rapid and significant changes in migration flows in response to economic,social,political and environmental factors,international migration can change si

299、gnificantly in volume and direction within a short timeframe.Because of these challenges,international migration was projected on the basis of past international migration estimates,assuming a continuation of recent migration trends in countries with stable migration levels as well as taking into ac

300、count the policy stance of each country with regard to future international migration flows.The global population is expected to reach 9.7 billion in 2050 and 10.4 billion in 2100,according to the medium scenario,which assumes a decline of fertility for countries where large families are still preva

301、lent,a slight increase of fertility in several countries where women have fewer than two births on average over a lifetime,and continued reductions in mortality at all ages.There is inherent uncertainty in population projections.At the global level that uncertainty depends on the range of plausible

302、future trends in fertility,mortality,and international migration,which have been assessed for each country or area using demographic and statistical methods.This analysis concludes that,with a probability of 95 per cent,the size of the global population will stand between 9.4 and 10.0 billion in 205

303、0,and between 8.9 and 12.4billion in 2100.Sub-Saharan Africa will account for most of the growth of the worlds population over the coming decades,while several other regions will begin to experience decreasing population numbers.Sub-Saharan Africa is projected to become the most populous of the eigh

304、t geographic regions in the late 2060s,surpassing both Eastern and South-Eastern Asia and Central and Southern Asia in size(figure III.2),and it could see its population reach 3.44 billion by the end of the century.While population growth in Northern Africa and Western Asia has been slower than in s

305、ub-Saharan Africa in recent decades,the region is also projected to continue to grow through the end of this century,adding 221 million people between 2022 and 2050 and another 174 million people between 2050 and 2100.The worlds two most populous regions in 2022 are Eastern and South-Eastern Asia,wi

306、th 2.3 billion people,representing 29 per cent of the global population,and Central and Southern Asia,with 2.1 billion(26 per cent).Both regions,which experienced rapid population growth since the mid-twentieth century,are expected to reach their peak population size in the coming decades.Eastern an

307、d South-Eastern Asia is projected to reach a maximum population size of 2.4 billion around 2034 and the population of Central and Southern Asia is projected to peak some 38 years later at 2.7 billion around 2072.The combined population of Europe and Northern America is stabilizing,having reached 1.1

308、2 billion in 2022 and,according to the medium scenario,projected to grow slowly to just under 1.13 billion around 2038 and decline thereafter to about 1.0 billion at the end of the century.The population of Latin America and the Caribbean,which quadrupled in size between 1950 and 2022,is projected t

309、o peak at just below 752 million around 2056 and decline thereafter to about 646 million in 2100.The population of Oceania is projected to continue to grow through the end of the century.The total population of the region,excluding Australia and New Zealand,is expected to increase from 13.6 million

310、in 2022 to 19.6 million in 2050 and 24.6 million in 2100.Australia and New Zealand,which are home to 31.2 million people in 2022,could see their population grow to 38.1million in 2050 and 44.2 million in 2100,according to the medium scenario.World Population Prospects 2022:Summary of ResultsUnited N

311、ations Department of Economic and Social Affairs,Population Division29Figure III.2Population by SDG region:estimates,1950-2022,and medium scenario with 95 per cent prediction intervals,2022-2100Another means of exploring the potential variability of future population trends involves making specific,

312、stylized changes in the assumptions about future levels and trends of fertility,mortality and migration.This(deterministic)exercise resulted in nine scenarios that illustrate the impact on projected population trends of hypothetical changes in the underlying assumptions(box III.1).In the high-and lo

313、w-fertility scenarios,the future fertility level for each country or area is assumed to be consistently higher or lower than in the medium scenario by exactly one half(0.5)of a birth per woman,on average,while retaining the same assumptions with respect to mortality and international migration.As il

314、lustrated in figure III.3,the trends in global population size associated with the high-and low-fertility scenarios diverge considerably from the trajectory of the medium scenario and imply a range of future outcomes that is much broader than the prediction intervals of the probabilistic analysis.Th

315、e probabilistic assessment of projection uncertainty suggests that the range between the high-and low-fertility scenarios may be implausibly large,especially in the latter decades of the current century.The medium scenario of global trends is derived by aggregating the“best guess”projections for ind

316、ividual countries and areas.Although a deviation of half(0.5)of birth between actual and projected fertility levels is entirely plausible for a given country or area in a given year,it is unlikely that this would be the case for all countries and areas and for all future years as implied by the trad

317、itional high-and low-fertility scenarios of the United Nations population projections(Gerland and others,2014).World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division30Figure III.3Global population size:estimates,1950-2022,and me

318、dium scenario with 95 per cent prediction intervals and high-and low-fertility scenarios,2022-2100Besides the probabilistic and deterministic population projections released by the United Nations,other institutions produce long term population projections.The latest sets of three shared socio-econom

319、ic pathways(SSPs)published by the Joint Research Center of the European Commission(JRC)outline alternative scenarios illustrating a broad range of possible futures(European Commission,Joint Research Center,2018).The first of these scenarios,SSP1,labelled Sustainability/Rapid Social Development,assum

320、es an acceleration of the demographic transition through sustained investments in education and health that would contribute to future low levels of mortality and fertility.The second scenario,SSP2,labelled Continuation/Medium Population Scenario,is considered as the most likely future based on tren

321、ds of recent decades and assumes a medium pathway in future fertility,mortality and education.The last scenario,SPP3,labelled Fragmentation/Stalled Social Development,is characterized by rapid population growth accompanied by low education,and high mortality and fertility.Global population levels ar

322、e lowest in SSP1,peaking at 8.7 billion between 2050 and 2060,and declining to 7.3 billion by 2100(figure III.4).This is broadly consistent with the United Nations low-fertility scenario.Under SSP2,the middle-of-the-road scenario,the future population would peak around 9.7 billion in 2070.This figur

323、e is still lower than the United Nations medium scenario of around 10.4 billion in 2100.Finally,SSP3 shows continued global population growth through to the end of the century,reaching 13.6 billion by 2100.SSP3 is higher than the United Nations medium scenario,but still below the high-fertility scen

324、ario(figure III.4).In sum,at the global level,the lowest SSP trajectory lies close to the United Nations low-fertility scenario.However,while the traditional“low-and high-fertility”scenarios of the United Nations may be plausible for high-fertility countries individually,they depict rather unlikely

325、outcomes for regional and global aggregates(Gerland and others,2014).World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division31Alternative long-term population projections have also been undertaken by the Institute of Health Metri

326、cs and Evaluation(IHME).In its recent projections,IHME projected that the global population will reach 8.8billion in 2100 with a range of 6.8 billion to 11.8 billion(figure III.4).The main difference between the projections released by IHME and the United Nations lies in the assumptions on the futur

327、e level of fertility.IHME projects that the global level of fertility will decline faster than under the United Nations medium scenario.According to IHME,the average number of children per woman will decline to 1.66 children at the end of the century while the United Nations projects fertility to be

328、 around 1.84 at the same date.Figure III.4Comparisons of long-term global population projections under various scenarios,United Nations,IHME and JRC,2022-2100Sources:-IHME series:Institute for Health Metrics and Evaluation(IHME)(2020).Global Fertility,Mortality,Migration,and Population Forecasts 201

329、7-2100.Seattle,United States of America:Institute for Health Metrics and Evaluation(IHME).https:/doi.org/10.6069/MJND-3671.JRC series:Wittgenstein Centre for Demography and Global Human Capital(2018).Wittgenstein Centre Data Explorer Version 2.0.Available at:http:/wittgensteincentre.org/dataexplorer

330、.For example,with a total fertility rate of 1.7 births per woman in 2100,IHME projects a faster decline of fertility in sub-Saharan Africa than the United Nations medium scenario,which projects a total fertility rate of 2.0 at the end of the century(figure III.5).This difference of 0.27 births per w

331、oman in 2100 results in a population that is 378 million lower than projected by the United Nations medium scenario.At the national level,the differences in the fertility rate between the two sets of projections by 2100 can be more substantial,with 1.79 births per woman instead of 2.22 in Niger or 1

332、.33 births per woman instead of 1.87 in Ethiopia,for example.In India,IHME projects a total fertility rate of 1.29 births per woman in 2100 instead of 1.69in the United Nations medium scenario,resulting in a population that is 433 million smaller than according to the United Nations projections at t

333、he end of the century.World Population Prospects 2022:Summary of ResultsUnited Nations Department of Economic and Social Affairs,Population Division32Figure III.5Comparison of long-term fertility projections,sub-Saharan Africa,2022-2100,United Nations medium scenario and IHME reference scenarioData source:-IHME series:Institute for Health Metrics and Evaluation(IHME)(2020).Global Fertility,Mortali