challenge 1: population growth

It took many 1.000s of years for the world population to grow to 1 billion – then after just some 100+ years, it grew by another billion. The next billion took a mere 30 years, and the next 20 years and the next only 10…..

In 2020 it stands at about 7.8 billion people living on planet earth, and it’s expected to grow to approx. 9.7 billion in 2050. An extra 2 billion human beings…

This exponential growth and more recent developments have been driven by several factors:

  • Increasing numbers of people surviving to reproductive age [better health conditions]. Average global lifespans have risen from approx. 65 years in the early 1990s to nearly 73 years in 2019.
  • Important changes in fertility rates [especially because of increased living standards and – therefore – better-educated women]. In the early 1970s women had on average 4.5 children each, which by 2015 had fallen to below 2.5.
  • Increased urbanization and accelerating migration.
  • As from the beginning of this millennium more people lived in urban areas than in rural areas, and by 2050 about 2/3 of the world population will be living in cities. 

The demographic development in the coming decennia will differ vary substantially between countries and continents, mainly because of the large dissimilarities in the age structure of their populations:






The age distribution of China is more or less similar to that of Europe and the USA. On the other hand, those of India and especially Africa are very different. Here, the scope of the age categories lies emphatically with the young.

This means that the increase in the world population of approximately 2 billion people between now and 2050 will mainly take place in India and especially Africa.

What happens can very well be explained by this illustration that was published in The Economist in 2006. In a century the “pyramid” shifts to a “kite”.

This example concerns Japan.


All these megatrends have far-reaching implications, especially since they are interconnected. They affect the necessary government policies for economic development and employment, income distribution, and universal access to better housing, food, water, sanitation, energy, health care, and education.