World urbanisation prospects: an alternative to the UN model of projection compatible with urban transition theory

Philippe Bocquier, Institut de Recherche pour le Développement (IRD)

This paper proposes to critically examine the UN projections of urbanisation. Both the estimates of the current trends based on national data and the method of projection are evaluated. The theory of urban transition is used as an alternative hypothesis for projections and adapted to account for the increasing economic discrepancies among the various regions of the world. Alternative projections are proposed using a polynomial model and compared with the UN projections based on a linear model. The conclusions are that UN projections may overestimate the urban population for the year 2030 by almost one billion, or 19% in relative term. The overestimation would particularly affect developing countries and may exceed 30% in some less developed regions in Africa, India and Oceania.