World Urbanization Prospects: an alternative to the UN model of projection compatible with urban transition theory

This paper proposes to critically examine the United Nations projections on urbanisation. Both the estimates of 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. Alternative projections are proposed using a polynomial model and compared to the UN projections, which are 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 be particularly more pronounced for developing countries and may exceed 30% in Africa, India and Oceania.