Drivers of future population growth in six most populous countries: Effect of demographic components on the population growth using decomposition analysis

Abstract

Background: Long-term population projections are useful exercises to help us study population dynamics and set up suitable policies and programmes. Release of the UN 2022 world population prospects data enables us to estimate the effects of demographic factors on future population growth. Methods: Relative contributions of demographic factors influencing future population growth are routinely identified using decomposition technique and that has been used in this paper. Six most populous countries have been considered for the analysis and the recently released 2022 Revision of World Population Prospects data used. Results: Results of decomposition analysis of population growth in six most populous countries and the total population suggest that population momentum continues to influence the population growth in the six most populous countries of the world in coming decades. However, influence of fertility on population growth has started to reverse in China, India, and Indonesia while it continues to be a significant factor in population growth in Nigeria and Pakistan. Gains in mortality steadily gather momentum in increase of population growth in all the six countries in coming decades. Migration marginally effects India’s population decrease whereas, it positively influences the USA’s population. Conclusions: The decomposition of variation in population growth into the relative contributions from different demographic rates has multiple uses in demography and formulating population policies.  Such studies are important in assessing countries’ positions in demographic transition in taking appropriate policy decisions. This century is going to witness unprecedent demographic transitions at varying levels with some countries struggling to manage ultra-low fertility leading to decline in population scenario to countries with high fertility leading to doubling of population size.