The United Nations released some new population projections last week that are worth taking a closer look at.
The news coverage about the reports hit the high points: the UN projects that the world’s population will reach 9.6 billion by 2050, and India could overtake China as the most populous nation around 2028.
But a lot of the stories I’ve seen have missed two key points that are worth calling out.
First, life expectancy has been going up at an historic rate. You may know that the average life span went up in the 20th century—but did you know it increased faster in the past 100 years than at any other time in history? Life spans rose by nearly 50 percent, from 47 years in the 1950s to 69 years in 2010. And the U.N. projects that the average will keep going up for the rest of this century.
Of course, the average obscures a lot of variation among countries. In most rich countries today, the average life span is over 75 (in Japan it’s over 80), while in the poorest it is only 58. But even in those poor countries, the UN projects that life spans will reach 70 years by the middle of this century.
So if anyone tries to tell you how much better things were in the old days, you can ask them if they preferred it when 20 million kids a year died before age 5 (versus about 7 million today) and the average human being died before age 50.
That leads to the second point, and it’s a really important one:
As child mortality goes down, families get smaller. It’s counterintuitive, but it becomes crystal-clear when you look at the data: Just about all the countries where health is still bad also have high birth rates. And as more children in a country survive past age 5, the number of children born per woman goes down. It’s happened in China, India, Indonesia, Iran, Brazil, and South Africa, among other countries.
Why does this happen? Because when parents know their children will live long enough to support them in their old age, they decide to have fewer kids. The economist Jeff Sachs has written a lot about this point. The Swedish researcher Hans Rosling nailed it a few years ago in a brilliant and entertaining TED talk.
Of course, it’s one thing for people to want smaller families, and another for them to be able to act on this wish. That’s why it’s so important to make sure women have access to voluntary family planning, which our foundation does a lot of work on and is a big focus for Melinda.
These two facts—increasing life spans and the strong link between family size and child health—drive a lot of the work Melinda and I do. They tell us that the world is getting better; that the challenge is to make sure it gets better faster, and for everyone; and that one of the best ways to do that is by working to save children’s lives and supporting family planning. When health improves, life improves, by every measure.