The Demographic Transition, with Data from Brazil

Abstract

The demographic transition—the process through which declines in mortality precede declines in fertility, leading to a period of population growth and the long-term restructuring of the age composition—holds remarkable power to explain the state of our social world. In this visualization, I employ Brazilian demographic measures dating back to the 1870s to depict the interplay between mortality, fertility, growth rates, dependency ratios, and total population size within a single three-panel figure with a shared time axis. Over the course of nearly two centuries, fertility and mortality differentials contribute to a staggering 18-fold increase in Brazil’s population size and a dramatic rise in the proportion elderly. Although the data are drawn from a single country, Brazil’s patterns of demographic change are representative of those experienced in many other populations. A graph of demographic transition-era population dynamics alongside an understanding of various world regions’ positions along the x -axis can help to answer innumerable questions of great social importance.