Our planet is now home to seven billion people, with ravenous appetites for fuel and food — and the number keeps growing. Do you panic when you think about the expansion of the human race? Yes, the world faces great challenges but it is possible to solve them, and some are in fact already being solved.

I’m a statistician — but don’t stop reading. Because the latest demographic data show that the future may not be that gloomy, and that mankind is already doing better than many of us think.

In 1800, the world’s population stood at barely one billion. But with the industrial revolution everything changed, and in little more than a hundred years, the population reached two billion and then, when I was at school, three billion. Now we are seven billion. More than half of the world’s population has been added during my lifetime and the number is still rising.

Yet paradoxically, the number of children in the world is not going to rise from now on. Let me first bust a few myths. How many babies do Bangladeshi women have on average — 2.5, 3.5, 4.5 or 5.5? We posed the question to Britons, and most chose 4.5 and 5.5. The right answer is 2.5 (in fact, by now it’s actually 2.2). This is what Brits don’t know: that in Bangladesh — and also in Brazil, Vietnam, India and big African cities like Addis Ababa — two-child families are the norm. This change from big families down to two-child families is one of the most important things to happen in my lifetime. It’s unprecedented in human history. It also means that we’ll see the end of fast population growth by the end of this century.

Hans peak child

Here’s the thing. Around 2000 we reached the period of ‘peak child’ — from then on, the number of people under the age of 15 stayed at about two billion of the global population, and shouldn’t grow from that proportion from now on. But how can this be, you may ask, if the world population has been rising so much? The answer lies in better education and family planning versus higher child survival rates, in how the former came to outbalance the latter.

The population growth since 1800 was due to a much longed-for drop in child mortality. A wonderful thing occurred, which is that medical advances meant fewer people died in childhood, while humans in general could expect to live longer. In 1972, the year of Bangladesh’s independence, there was on average seven babies per woman, and the lifespan was less than 50 years. Today, the average Bangladeshi family has 2.2 children, while life expectancy is 70. Now, the statistical 2.2 children are much more likely to survive to old age — but that doesn’t mean a continuous fast population growth, because the number of children being born has fallen dramatically. (Greater longevity does mean that old people like me will be sticking around on earth longer than we used to, but we won’t make up that significant a chunk of the global population.)

This pattern is occurring everywhere — especially in countries like China and India, which people normally think of as contributing most to the population ‘explosion’. Fifty years ago, the global average number of babies born per woman was five; today it’s 2.5 and decreasing. People think that countries like Bangladesh are the epicentre of a population bomb but they couldn’t be more wrong.

The one place where the population is still set to boom is Africa, but even there, with better education, family planning and economic opportunities, people could slowly but steadily reach the ‘peak child’ stage. By 2050, Asia will have one billion more people — then its population growth is over. During this time, Africa’s population will double to two billion, and is set to double again to four billion by 2100. By the end of the century, with no more population growth in Europe, the Americas and Asia, there will be 11 billion people on earth, with four billion of that in Africa.

Hans population graph

By 2100, eighty percent of the world’s population will be in Africa and Asia. The big question is: will there be resources enough to sustain them? Thirty years ago, I spent the two most intense years of my life working as a medical doctor in one of the poorest countries, Mozambique. Conditions were miserable. Today Mozambique is still a very poor country but things have improved immensely— there’s a brand new hospital in the town where I used to work, where all the staff are well trained and routinely save women in childbirth by performing Caesareans. Such examples can be found throughout Africa, which is developing just as Asia did.

Education is key. Here’s another question we posed to British people: what’s the literacy rate of the world — 20, 40, 60 or 80 percent? Half chose 20 and 40 percent, nearly 45 percent of them chose 60 percent, and only 8 percent picked 80 percent. The answer, of course, is 80 percent (and rising). Four-fifths of the world can read and write, and thus hold the means to pull themselves out of poverty. You see? Our perception of things is very different from the reality.

I am not an optimist, but I do call myself a possiblist. And I say the world is much better than many think.

Watch numbers guru Hans Rosling on iPlayer presenting ‘Don’t Panic: The Truth About Population.

Tags: birth, Population, Statistics