Visualizing How A Population Grows To 7 Billion

Oct 31, 2011

The U.N. estimates that the world's population will pass the 7 billion mark on Monday.

Much of that growth has happened in Asia — in India and China. Those two countries have been among the world's most populous for centuries. But a demographic shift is taking place as the countries have modernized and lowered their fertility rates. Now, the biggest growth is taking place in sub-Saharan Africa.

Due in part to that region's extreme poverty, infant mortality rates are high and access to family planning is low. The result is high birth rates and a booming population of 900 million — a number that could triple by the end of the century. Population expert Joel Cohen points out that, in 1950, there were nearly three times as many Europeans as sub-Saharan Africans. If U.N. estimates are correct, there will be nearly five sub-Saharan Africans for every European by 2100.

As NPR's Adam Cole reports, it was just over two centuries ago that the global population was 1 billion — in 1804. But better medicine and improved agriculture resulted in higher life expectancy for children, dramatically increasing the world population.

As higher standards of living and better health care are reaching more parts of the world, the rates of fertility — and population growth — have started to slow down, though the population will continue to grow for the foreseeable future.

U.N. forecasts suggest the world population could hit a peak of 10.1 billion by 2100 before beginning to decline. But exact numbers are hard to come by — just small variations in fertility rates could mean a population of 15 billion by the end of the century.

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Today, somewhere in the world a newborn is nudging the Earth's population to seven billion. That's according to a U.N. estimate. Demographers really don't know when or where that baby will be born, but the U.N. is using today to mark symbolically the dramatic change in the population. As part of MORNING EDITION's series Seven Billion and Counting, we'll explore the significance of the number.


In a few minutes, we'll hear how two different countries are dealing with population growth. One of them is China, the world's most populous nation. The other is South Sudan and sub-Saharan Africa, where the population is expected to triple by the end of this century. First, let's go back in time - way back - to explore how we got to where we are today. Here's NPR's Adam Cole.

ADAM COLE, BYLINE: A thousand years ago, the world was a lot less crowded. There were only about 300 million people. That's the current size of the United States, a tiny fraction of the seven billion we have now. Let's say that one voice represents 100 million people. We'll take one voice from Europe...

UNIDENTIFIED MAN #1: (Foreign language spoken)

COLE: One from South Asia.

UNIDENTIFIED WOMAN: (Foreign language spoken)

COLE: And a third voice from China.

UNIDENTIFIED MAN #2: (Foreign language spoken)

COLE: Even back then, China and India were the most populated regions in the world. OK, so here we are in the 11th century with our three voices. How do we get from that 300 million people a thousand years ago to the seven billion people we have now? We have to travel forward in time at about 10 years per second.


COLE: In just five seconds, we've already passed through 50 years. The population is growing, but very, very slowly. Women are having lots of children...


COLE: ...but most of these children die before they're old enough to start families of their own. If we fast forward to the 18th century, we'll reach 900 million people. And in 1804 we'll hit our first billion.


COLE: OK. Let's stop the clock for a moment. Things are about to get crazy. We're entering an age of better medicine and better agriculture, and that means lower death rates. Women are still having lots of children, but now most of those children are surviving to have children of their own, and their children are having even more children. You can see where this is going. OK. Let's start up again. We'll hit our second billion in 1927.


COLE: And then things really take off.


COLE: There's three billion.


COLE: Four billion.


COLE: Five billion.


COLE: Six billion.


COLE: Seven billion. Seven billion people - over five billion of them added in the last 100 years. It's easy to see that the planet has gotten pretty crowded pretty fast, but it's not so easy to predict future growth or understand how this population explosion might affect each of us. Adam Cole, NPR News.

MONTAGNE: And to see a really cool video on how the world came to have seven billion people, go to our website, Transcript provided by NPR, Copyright National Public Radio.