The Rapid Slowdown of Population Growth

We are living in a paradoxical time of population growth. In the media, there have been alarming reports asking how the world will be able to deal with a much larger population in years to come. The challenges are real, especially in Sub-Saharan Africa, whose population is expected to double by 2050 and possibly quadruple by 2100. At the same time, we have been experiencing the most rapid decline in global population growth ever.

But how can we reconcile those two facts: a rapid expansion of total population numbers with a fast slowdown of population growth? Here is an analogy from the world of cars: imagine you are driving on a German motorway, where speed limits are notoriously non-existent. You are cruising at 160km/h (100m/h) but soon you cross the border into France, where 130 km/h is the limit. You are still driving very fast, though substantially slower than before. Now you switch to a regional road, driving at 80km/h, and now you slow down further to 50 km/h as you enter into a town. Meanwhile, someone else is still driving at 160 km/h on that Autobahn.

Global population growth is following a similar path. Even though we are still growing at a high rate the slowdown has already started and we will never revert to the high speed we had in the past. We have already passed two historical peaks of global demography a few decades ago:

• In 1968, we reached the relative peak in global population growth rate. Then, the world grew at a record 2.09 percent – adding 73.2 million to a world population of 3.54 billion. This historical peak was part of a seven-year high-growth period – from 1966 to 1972 – and the only time in recorded history when the world’s population grew above two percent. I was also born at that time.
• In 1988, just before the fall of the Berlin wall, we reached the absolute peak in global population growth (i.e. in the number of people added). The world gained almost 93 million people and since then world population growth has been declining also in absolute terms.

Today, the world is adding 81 million people a year, which is still significant and similar to the size of Egypt or Germany. But the relative growth of the world population is almost in free fall. It is expected to decline to 1 percent in 2020 (adding 76 million to 7.6 billion people), the lowest rate since the 1950s. Moreover, this trend is set to continue: by 2050, the global population growth rate will be below 0.5 percent (see figure), bringing us back to 17th and 18th century figures. The absolute number will decline in equal measure. By 2050, we will be adding only 46 million people a year (see Figures 1 and 2). 
 

Source: Created by Emi Suzuki,                  

These averages, though, mask enormous regional differences. Africa is still growing at a rate close to the world's highest ever recorded level: higher than two percent per year. Europe by contrast is hardly growing at all, while Asia is expending in line with the global average of around one percent.

But if population growth is declining, what justifies the alarmist statements and doomsday scenarios that the press is echoing? Could we have expected an even more rapid slowdown?

The neo-Malthusian assumption is that bigger populations will translate into greater disempowerment and deeper poverty. But that’s partly a "reverse causality fallacy," because most humans have been disempowered and poor all along. In most of the world’s history, high rates of fertility coincided with widespread misery, but the causality probably ran the other way. People had many children because they were so poor. Moreover, the world population didn’t grow much until the early 20th century because mortality remained high. Only once people became better off, when improvements in health, sanitation and nutrition were made available to a larger part of society, did world's population start to rise rapidly. This was the beginning of our journey from 1 billion to 10 billion people, a threshold we are expected to reach by 2060.

We are fortunate to live in a unique time. The period between 1950 and 2050 will go down in history as the time of the global demographic transformation that may remain unmatched forever. Learning from the successes of the last decades, we will need to enter the last frontier of poverty reduction, of child and maternal mortality, of illiteracy and disempowerment, so that everyone will be able to live longer, happier lives.