On the limits of application of the UN population projections

Abstract

The last few years have seen a significant growth of interest in UN population projections. The latest such projection made by the UN Population Division was published in 2017, and is, on the whole, in agreement both with previous UN projections and projections conducted by other institutions. According to the 2017 Revision, world population size will reach 9.772 billion persons in 2050 and 11.184 billion in 2100. However, these dry figures themselves cannot explain the appearance of harsh criticism of these projections. This paper aims to get a better grip on the real reason for this criticism – the new methods used in these projections and their significant reworking, or the results themselves. For this purpose, an analysis is made of the recent UN projections, their methods, the data used, and the results of projections made in the last 15 years. Shortcomings of the UN projections are discussed, as well as the limitations and conditionality of their possible use. It is shown that among the possible reasons for an increase in projected world population, the most significant ones include: 1) the overestimate of projected infant and child mortality in previous projections, and 2) the underestimate of the rate of fertility decline in several African countries. It is argued that short-term population projections should be trusted and may be used for practical purposes, while the conditionality of applying long-term projections, for which there are multiple possible unpredictable factors of future demographic development, significantly reduces their precision. For particular countries, a great uncertainty of long-term projection may be caused by a sharp change in population policy or sociopolitical organization. This is illustrated by examples for several countries.