This blog is intended to go along with Population: An Introduction to Concepts and Issues, by John R. Weeks, published by Cengage Learning. The latest edition is the 12th (it came out in 2015), but this blog is meant to complement any edition of the book by showing the way in which demographic issues are regularly in the news.

If you are a user of my textbook and would like to suggest a blog post idea, please email me at: john.weeks@sdsu.edu

Friday, September 8, 2017

The Drop in Child Mortality Helps Explain the Population Explosion

Many people in the world have the view that the population explosion is a thing of the past. After all, the world's rate of growth is lower now than it was back in 1968 when Paul Ehrlich's The Population Bomb was published. Indeed, the rate of growth peaked at about that time...but not the number of people being added each year. The 84 million people being added to the world each year right now is a greater number than were being added when the rate of population growth was nearly twice what it is now. We're building on an ever bigger base of people, so even a low rate of growth adds a lot of people. Figure 2.3 in my text gives you this information graphically.

Why do I mention this? Because Max Roser at Oxford has put together another really informative and useful (and interactive) graphic on child mortality (deaths to children under age 5) over time. The increasing survival of children is the single most important cause of population growth in the world, since it almost never is accompanied early on by a compensating drop in fertility. Everyone wants children to survive--not everyone wants to use birth control. Here is the graphic:


You can see that Sweden and France experienced long-term and relatively slow declines in child mortality. In the 19th and early 20th centuries Europeans, in particular, were figuring out the value of vaccinations and, on top of that, incomes were generally rising so people were eating better and living in cleaner environments. It was only after WWII, however, that death control technology was actively spread around the world, and child mortality rates responded quickly. This graph shows Ghana (where I am currently analyzing child mortality at the neighborhood level), Iran and South Korea. You can modify the map yourself if you go the website

These very rapid declines in child mortality were eventually met by rapid drops in fertility in South Korea and Iran (both of which are currently below replacement level) and a considerable drop in Ghana as well--even though still well above replacement level. The gap between when child mortality drops and fertility responds with an equivalent drop is what generates the population explosion--and it's still happening, folks.

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