Letter | Published:

The coming acceleration of global population ageing

Nature volume 451, pages 716719 (07 February 2008) | Download Citation

Abstract

The future paths of population ageing result from specific combinations of declining fertility and increasing life expectancies in different parts of the world1. Here we measure the speed of population ageing by using conventional measures and new ones that take changes in longevity into account for the world as a whole and for 13 major regions. We report on future levels of indicators of ageing and the speed at which they change. We show how these depend on whether changes in life expectancy are taken into account. We also show that the speed of ageing is likely to increase over the coming decades and to decelerate in most regions by mid-century. All our measures indicate a continuous ageing of the world’s population throughout the century. The median age of the world’s population increases from 26.6 years in 2000 to 37.3 years in 2050 and then to 45.6 years in 2100, when it is not adjusted for longevity increase. When increases in life expectancy are taken into account2,3, the adjusted median age rises from 26.6 in 2000 to 31.1 in 2050 and only to 32.9 in 2100, slightly less than what it was in the China region in 2005. There are large differences in the regional patterns of ageing. In North America, the median age adjusted for life expectancy change falls throughout almost the entire century, whereas the conventional median age increases significantly. Our assessment of trends in ageing is based on new probabilistic population forecasts. The probability that growth in the world’s population will end during this century is 88%, somewhat higher than previously assessed4. After mid-century, lower rates of population growth are likely to coincide with slower rates of ageing.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1.

    United Nations. World Population Ageing 2007 (United Nations, New York, 2007)

  2. 2.

    & Average remaining lifetimes can increase as human populations age. Nature 435, 811–813 (2005)

  3. 3.

    & A new perspective on population aging. Demog. Res. 16, 27–58 (2006)

  4. 4.

    , & The end of world population growth. Nature 412, 543–545 (2001)

  5. 5.

    Ageing Societies: Myths, Challenges and Opportunities (Hodder Arnold, London, 2006)

  6. 6.

    Notes on stationary populations. Popul. Index 41, 3–28 (1975)

  7. 7.

    De la démographie actuelle à la démographie potentielle. Melange des Études Economiques Offertes à William Rappard (Georg, Geneva, 1944)

  8. 8.

    & Potential demography. Eur. J. Popul. 12, 27–39 (1996)

  9. 9.

    How long do we live? Popul. Dev. Rev. 32, 605–626 (2006)

  10. 10.

    & Broken limits to life expectancy. Science 296, 1029–1031 (2002)

  11. 11.

    & A realistic view of aging, mortality and future longevity. Popul. Dev. Rev. 33, 367–381 (2007)

  12. 12.

    National Research Council. Beyond Six Billion: Forecasting the World’s Population (eds Bongaarts J. & Bulatao R., Panel on Population Projections, Committee on Population, Commission on Behavioral and Social Sciences and Education) (National Academy Press, Washington DC, 2000)

  13. 13.

    & Modeling and forecasting U.S. mortality. J. Am. Stat. Assoc. 87, 659–671 (1992)

  14. 14.

    , & Limits to human life expectancy: evidence, prospects and implications. Popul. Dev. Rev. 17, 603–637 (1991)

  15. 15.

    Aging, natural death, and the compression or morbidity. N. Engl. J. Med. 303, 130–135 (1980)

  16. 16.

    Ex-post errors in official population forecasts in industrialized countries. J. Off. Stat. 13, 245–277 (1997)

  17. 17.

    United Nations. World Population to 2300 (and associated database) (United Nations, New York, 2004)

  18. 18.

    , , , & China’s uncertain demographic present and future. Vienna Yb. Pop. Res. 2007, 37–59 (2007)

  19. 19.

    , & in The End of World Population Growth in the 21st Century: New Challenges for Human Capital (eds Lutz, W., Sanderson, W. & Scherbov, S.) 17–84 (London, Earthscan, 2004)

Download references

Author information

Author notes

    • Wolfgang Lutz
    • , Warren Sanderson
    •  & Sergei Scherbov

    These authors contributed equally to this work.

Affiliations

  1. World Population Program, International Institute for Applied Systems Analysis, Schlossplatz 1, A-2361 Laxenburg, Austria

    • Wolfgang Lutz
    • , Warren Sanderson
    •  & Sergei Scherbov
  2. Vienna Institute of Demography, Austrian Academy of Sciences, Wohllebengasse 12–14, A-1040 Vienna, Austria

    • Wolfgang Lutz
    •  & Sergei Scherbov
  3. Departments of Economics and History, State University of New York at Stony Brook, Stony Brook, New York 11794-4384, USA

    • Warren Sanderson

Authors

  1. Search for Wolfgang Lutz in:

  2. Search for Warren Sanderson in:

  3. Search for Sergei Scherbov in:

Corresponding author

Correspondence to Wolfgang Lutz.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    The file contains Supplementary Tables 1-3 and Supplementary Figure 1.  The Supplementary Information shows the results of IIASA’s new probabilistic population projections for 13 world regions and for the world as a whole (selected indicators for selected years). Information about more indicators and for single years of time can be found at http://www.iiasa.ac.at/Research/POP/proj07/index.html?sb=5 or directly from the corresponding author

About this article

Publication history

Received

Accepted

Published

DOI

https://doi.org/10.1038/nature06516

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.