Over 400,000 people visited Farnam Street last month to learn how to make better decisions, create new ideas, and avoid stupid errors. With more than 100,000 subscribers to our popular weekly digest, we've become an online intellectual hub. To learn more about we what do, start here.

Hans Rosling’s Important Truths about Population Growth and the Developing World

Garrett Hardin’s Living Within Limits had a huge influence on how I thought about population.

In the book, he convincingly demonstrates the folly of allowing human population to grow unchecked over a long enough timeframe. Even a small rate of compound would add up to large figures. Hardin’s argument can be summed up fairly simply: An exponentially expanding population in a world with defined limits creates a problem. (An example of where scale has an effect on values.)

Hardin was clear to acknowledge that he wasn’t sure where the limits actually were. As supporters of Thomas Malthus have found out over the years, agricultural and other technology can and has outpaced population growth. But it was a certainty that some limits can not be overcome as long as we’re a single planet species — things like natural beauty, energy consumption, water consumption, fertilizer, living space, and other things mostly have limits. (Again, where those limits are is up for debate, and a certain Mr. Musk would like to make us multi-planetary as well.)

Hardin also gave us the terminology of a longage, as opposed to a shortage. Our terminology refers to a population without enough to eat as having a shortage of food. Hardin claimed it was equally correct to say there was a longage of people relative to the available resources.

Mostly, this was all I knew on the topic. Enter Hans Rosling to continue that education.

***

Hans Rosling is a Swedish academic and scientist who came to popular fame as a TED speaker. Among his talks are discussions on poverty, HIV, and the developing world. A few minutes tell you that man has a way with statistics and data presentation. (One of his talks is titled Let My Dataset Change Your Mindset.)

Rosling’s favorite twin topics are ones of population growth and the truth about what’s happening in developing countries — a truth the developed world doesn’t know much about. Are the world’s poorer nations like India, Bangladesh, Nigeria, and Mozambique going to go on exploding world population forever? What does this mean for the world? What are they living like now, what is their future? How does that affect the future of the developed world?

In the wonderful hour-long video above, Rosling blows up some misconceptions and misunderstandings, and convincingly makes the following points:

  • Population growth should hit a limit around 11 billion within the next hundred years, as the world equalizes in health outcomes.
  • In developed countries, a ratio near 2 parents to 2 children mostly exists and developing nations are getting closer and closer as their childhood health outcomes continue to improve. (And they have improved drastically.)
  • Stated another way, as a result of equalizing health outcomes, low child mortality, and family planning, family sizes go down, and population growth slows in a predictable way.
  • Current population trends are strong enough that by 2100, only ~10% of the world population will be in Western nations (North America, Western Europe) — Africa will quadruple in population and Asia will increase about 25%. It will be a very different world.
  • After an explosion of births in the second half of the 20th century, the number of children worldwide has already leveled off at around 2 billion, and should stay there at least through the century, barring a major development. Population growth from here will mostly be determined by more 30-85 year olds existing in the future than now. (In other words, births are nicely leveling off, but population growth must continue for a while anyways as the current crop of children grow up and have 2 children each. We currently have a very young world.) Watch from minute 22:00 or so for this counter-intuitive conclusion.
  • There are three or four income “groups,” roughly defined, across the planet — most of you reading this are in the $100/day or more income bracket. We’re extremely fortunate. Then, a major swath in the $10/day bracket. And then the world’s poorest, around $1/day. There’s also a big group with less than that. (Of course, there are also the super rich in the $1000/day+ bracket — it works in a power-law like fashion). One problem for those of us at the top is that when we look down, we see the people living one order of magnitude down ($10/day) and two orders of magnitude down ($1/day) as the same. The difference between the two groups is at least as big as the difference between you and someone who makes 10x as much money as you. (And probably larger.)
  • An interesting way for “rich” Westerners to think about the above, which Rosling demonstrates in a genius way: The absolute poorest in the world, nearly a billion people, would love a good pair of shoes with which to walk. The people living around two orders of magnitude down from us (~$1/day) are struggling to afford a bicycle. Those living one order of magnitude down (~$10/day) are working to afford one car for the family. The richest billion fly in airplanes, and the super-wealthy fly in their own airplanes. It’s an interesting way to conceive of the stratas of the world and where we all stand.

Of course, one of Rosling’s more interesting points is that, when polled, most Westerners are fairly clueless about all of this.

For example, over 50% of Brits think that the average Bangladeshi mother births around 5 children — the actual answer is 2.5 (and declining). When they were asked what percentages of adults in the world are now literate, about half the Brits thought it was 40% or less — the actual answer is over 80% (and rising). (Not to pick on Brits — I doubt most Westerners would have done any better.)

He concludes with a discussion on energy: As billions are lifted out of poverty by improvements in health, education, and infrastructure, as is happening and seems likely to continue, their energy use goes up dramatically. Think about the stratas we discussed above: Bicycles to a car to airplanes to private jets. As hundreds of millions look to improve their lot, and are now able to do so, human power is replaced by machine power, which takes great amounts of energy. With 80% of it currently coming from fossil fuels, what will we do?

Rosling doesn’t really provide an answer and we too must quitclaim this problem, but simply admonishing Westerners to “chill out with your energy use” is probably not going to be effective. We’ll probably have to solve it with great engineering — and, in some, ways, we already are.

***

Returning to the question of population growth and limits, it’s hard to say where we’ll end up with all this. Hard to say. Technology will have to solve many of the largest problems: Energy, emissions, water, and food. Not to mention the survival of the species we co-habitate with. Cheap solar energy will go a long way towards alleviating some strains. (Hurry up, Elon!)

But in the end, it’s a subject worth spending some time learning about. We can’t think about the problems unless we understand their parameters, or as some smart wag once said: “A problem well-defined is half-solved.”