Global aging will peak during the decade 2020 to 2030 and then decelerate

The world will experience a significant acceleration in the speed of population aging over the coming years but slow down by mid-century, according to a study by Warren Sanderson, Professor and Co-Chairman of the Department of Economics, Stony Brook University; and colleagues from the World Population Program at the International Institute for Applied Systems Analysis in Austria.

During the 21st century, global aging will peak during the decade 2020 to 2030 and then decelerate, although there will be further increases in the level of aging throughout the century. The research findings will be published in the January 20 online edition of Nature.

The study uses both traditional measures and new concepts that include changes in longevity to measure the speed of population aging in 13 major regions. Standard measures of aging are based on a fixed-age boundary, which, for example, assume that a 60-year-old person in 1900 was as old a 60-year-old person in 2000. Sanderson and the other researchers introduce and quantify three new indicators of age that explicitly take into account changes in the remaining life expectancy.

“The speed of aging is crucial to understand because it is during the period of the fastest change when adjustments will be the most difficult,” said Sanderson. “Policy-makers will need to know ahead of time when peak aging will occur so they can have those adjustments in place, especially those dealing with the financing of pensions and healthcare for the elderly.”

The timing of the peak speed of aging is based on past patterns of fertility. In the United States and in parts of Western Europe the timing is measured by when baby boomers start becoming elderly. In China, it is determined by the timing of the implementation of strict fertility control policies.

Dr. Sanderson's colleagues include Wolfgang Lutz and Sergei Scherbov, both of whom are with the World Population Program, International Institute for Applied Systems Analysis, Laxenburg, Austria and the Vienna Institute of Demography, Austrian Academy of Sciences, Vienna, Austria.

http://www.stonybrook.edu/