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Global population growth continuing

The United Nations released new population projections for all countries in July 2014. Gerland et al. analyzed the data and describe the probabilistic population projections for the entire world as well as individual regions and countries (see the Perspective by Smeeding). World population is likely to continue growing for the rest of the century, with at least a 3.5-fold increase in the population of Africa. Furthermore, the ratio of working-age people to older people is almost certain to decline substantially in all countries, not just currently developed ones.
Science, this issue p. 234; see also p. 163

Abstract

The United Nations (UN) recently released population projections based on data until 2012 and a Bayesian probabilistic methodology. Analysis of these data reveals that, contrary to previous literature, the world population is unlikely to stop growing this century. There is an 80% probability that world population, now 7.2 billion people, will increase to between 9.6 billion and 12.3 billion in 2100. This uncertainty is much smaller than the range from the traditional UN high and low variants. Much of the increase is expected to happen in Africa, in part due to higher fertility rates and a recent slowdown in the pace of fertility decline. Also, the ratio of working-age people to older people is likely to decline substantially in all countries, even those that currently have young populations.

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Supplementary Material

Summary

Materials and Methods
Table S1
References (2847)

Resources

File (gerland.sm.pdf)
File (gerland.sm.revision.1.pdf)

References and Notes

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Science
Volume 346 | Issue 6206
10 October 2014

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Submission history

Received: 16 June 2014
Accepted: 10 September 2014
Published in print: 10 October 2014

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Acknowledgments

We thank the entire team involved in the production of the 2012 Revision of the World Population Prospects—in particular, K. Andreev and F. Pelletier. We also thank two anonymous reviewers for helpful comments. This work was supported by NIH grants R01 HD054511 and R01 HD070936. A.E.R.’s research was also supported by a Science Foundation Ireland ETS Walton visitor award, grant reference 11/W.1/I2079. Views expressed in this article are those of the authors and do not necessarily reflect those of NIH or the UN.

Authors

Affiliations

Patrick Gerland*, [email protected]
Population Division, Department of Economic and Social Affairs, United Nations, New York, NY 10017, USA.
Adrian E. Raftery*, [email protected]
Departments of Statistics and Sociology, University of Washington, Seattle, WA 98195-4322, USA.
Hana Ševčíková
Center for Statistics and the Social Sciences, University of Washington, Seattle, WA 98195-4320, USA.
Nan Li
Population Division, Department of Economic and Social Affairs, United Nations, New York, NY 10017, USA.
Danan Gu
Population Division, Department of Economic and Social Affairs, United Nations, New York, NY 10017, USA.
Thomas Spoorenberg
Population Division, Department of Economic and Social Affairs, United Nations, New York, NY 10017, USA.
Leontine Alkema
Department of Statistics and Applied Probability and Saw Swee Hock School of Public Health, National University of Singapore, Singapore 117546.
Bailey K. Fosdick
Department of Statistics, Colorado State University, Fort Collins, CO 80523-1877, USA.
Jennifer Chunn
James Cook University Singapore, 600 Upper Thomson Road, Singapore 574421.
Nevena Lalic
Institutional Research, University of Washington, Seattle, WA 98195-9445, USA.
Guiomar Bay
Latin American and Caribbean Demographic Center (CELADE), Population Division of the United Nations Economic Commission for Latin America and the Caribbean, Santiago, Chile.
Thomas Buettner
Population Division, United Nations, New York, NY, USA.
Gerhard K. Heilig
Population Division, United Nations, New York, NY, USA.
John Wilmoth
Population Division, Department of Economic and Social Affairs, United Nations, New York, NY 10017, USA.

Notes

*
These authors contributed equally to this work.
Corresponding author. E-mail: [email protected] (P.G.); [email protected] (A.E.R.)
Retired.

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