Volume 28 - Article 39 | Pages 1145–1166  

Very long range global population scenarios to 2300 and the implications of sustained low fertility

By Stuart Gietel-Basten, Wolfgang Lutz, Sergei Scherbov

Abstract

Background: Depending on whether the global level of fertility is assumed to converge to the current European TFR (~1.5) or that of Southeast Asia or Central America (~2.5), global population will either decline to 2.3-2.9 billion by 2200 or increase to 33-37 billion, if mortality continues to decline. Furthermore, sizeable human populations exist where the voluntarily chosen ideal family size is heavily concentrated around one child per woman with TFRs as low as 0.6-0.8. However, the UN population projections to 2300 use a much narrower band of possible future TFRs.

Objective: If the two-child norm is not necessarily the end-point of transition, what would be the consequences of the currently reported low fertility rates being sustained and becoming widespread?

Methods: We present new projections for 13 IPCC world regions with scenarios calculated on the basis of regular cohort-component projections by age and sex in single-year time steps up to 2300, each based upon a much broader set of fertility assumptions than currently employed. We create three mortality scenarios based upon maximum life expectancies of 90, 100, and 110, as well as a series of ‘special’ scenarios.

Results: Even under conditions of further substantial increases in life expectancy, world population size would decline significantly if the world in the longer run followed the current examples of Europe and East Asia.

Conclusions: In contrast to Malthusian disaster scenarios, our exercise illustrates the distinct possibility of significant population shrinking associated with increasing life expectancy and human well-being.

Author’s Affiliation

• Stuart Gietel-Basten - Hong Kong University of Science and Technology, Hong Kong EMAIL
• Wolfgang Lutz - Wittgenstein Centre for Demography and Global Human Capital (IIASA, OeAW, University of Vienna), Austria EMAIL
• Sergei Scherbov - International Institute for Applied Systems Analysis (IIASA), Austria EMAIL

Other articles by the same author/authors in Demographic Research

Differences by union status in health and mortality at older ages: Results for 16 European countries
Volume 35 - Article 19

Does selection of mortality model make a difference in projecting population ageing?
Volume 34 - Article 2

Education stalls and subsequent stalls in African fertility: A descriptive overview
Volume 33 - Article 47

Certainty of meeting fertility intentions declines in Europe during the 'Great Recession'
Volume 31 - Article 23

Quantifying policy tradeoffs to support aging populations
Volume 30 - Article 20

How does education change the relationship between fertility and age-dependency under environmental constraints? A long-term simulation exercise
Volume 30 - Article 16

Modelling the constraints on consanguineous marriage when fertility declines
Volume 30 - Article 9

Significance of life table estimates for small populations: Simulation-based study of estimation errors
Volume 24 - Article 22

Gender equality and fertility intentions revisited: Evidence from Finland
Volume 24 - Article 20

Projection of populations by level of educational attainment, age, and sex for 120 countries for 2005-2050
Volume 22 - Article 15

A new perspective on population aging
Volume 16 - Article 2

Marriage in Russia: a reconstruction
Volume 10 - Article 2

Period Fertility in Russia since 1930: an application of the Coale-Trussell fertility model
Volume 6 - Article 16

Most recent similar articles in Demographic Research

Early unintended childbearing and unsecured debt in the United States
Volume 53 - Article 27    | Keywords: demography, fertility, gender, life course, mothers

Neighbors’ social attitudes predict variations in live births among the Amish of Holmes County, Ohio, United States
Volume 53 - Article 25    | Keywords: Amish, diffusion, fertility, household, proximity, religion, spatial analysis

Analysing migrant fertility using machine learning techniques: An application of random survival forest to longitudinal data from France
Volume 53 - Article 21    | Keywords: fertility, immigrants, machine learning, random survival forest, survival analysis

Universal yet local: Estimating county-level fertility ideals and intentions in China
Volume 53 - Article 18    | Keywords: China, fertility intention, multilevel model, poststratification, small area estimation

The partnership, fertility, and employment trajectories of immigrants in the United Kingdom: An intersectional life course approach using three-channel sequence analysis
Volume 53 - Article 10    | Keywords: employment, fertility, immigrants, multi-channel sequence analysis, partnership, United Kingdom