These 6 charts explain the world's looming demographic crisis

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The world is undergoing a profound demographic shift that will cause sweeping changes over the next few decades. 

Those changes will broaden the scope of our study of economics and investing; they will alter our understanding of sociology; and they will radically affect politics and governments.

Precisely what these changes will be is difficult to discern and predicting them requires some guesswork, but the one thing we don’t have to guess about is the demographic shift itself. 

Now, let’s begin with the big picture.

The world’s population could reach 14 billion by 2100

Experts think human population could fall to 6 billion or hit 14 billion until the end of this century. The gap is that wide because demographic projections require many assumptions. Small changes can combine to make a dramatic difference over time.

Uncertain future events could also bend the population curve. Baby booms and busts, wars, famines, epidemics, medical breakthroughs, and more are all potential game-changers. 

The late 20th century acceleration in population growth was mainly a result of modern vaccinations. Other technologies could have—and I think will have—similar impacts in the future.

Technology can cut the other way, too. We now have the capacity to wipe out entire nations with nuclear weapons. Some scientists think our excessive antibiotic use will create drug-resistant superbugs that could kill millions. I don’t expect such events, but we can’t rule them out, either.

For now, we are at least reproducing faster than we are dying. The result is a growing global population, which masks another problem.

Populations are shrinking in much of the developed world

If the global population is on the rise, it doesn’t mean it’s growing at the same rate in every country, or even growing at all.

We find the highest growth rates, for example, in sub-Saharan Africa and parts of the Middle East. The lowest growth is in Eastern Europe, Russia, China, and Japan. 

Notice the countries shown in shades of blue below. They are actually shrinking in population.

If you want your nation’s population to grow, you need a higher fertility rate and/or longer life expectancy. Africa has both factors on its side, though fertility rates are beginning to decline there, too.

Lifespans are growing almost everywhere

Falling fertility rates and longer lifespans mean that the global population is getting older. This will bring something remarkable in the next few years: the world will soon have more people over age 65 than it has children under 5.

You can see in the chart that the elderly population is growing much faster than the child population is shrinking. As our ability to extend lifespans grows, the disparity between these populations will get worse.