Changing Distribution of World Population

Source: United Nations.Opinion by Joseph Chamie (portland, us)Tuesday, March 04, 2025Inter Press Service

PORTLAND, US, Mar 04 (IPS) - As the world’s population increased five-fold since the start of the 20th century, the changes in the geographic distribution of the billions of people across the planet have been ongoing and significant.

Those continuing changes in the distribution of the world’s population have weighty economic, political, social and environmental consequences (Table 1).

Source: United Nations.

Particularly noteworthy are the changing proportions of the world’s population living in Africa and Europe. At the start of the 20th century the proportions of the world’s population residing in Africa and Europe were 8% and 25%, respectively. By the end of that century, the proportions were similar, 13% for Africa and 12% for Europe. By 2050, however, the proportions of the world’s population residing in Africa and Europe are expected to be very different at 26% and 7%, respectively (Figure 1).

Source: United Nations.

Moreover by the close of the 21st century, those proportions are projected to be 37% for Africa and 6% for Europe. In other words, whereas Europe’s population was three times the size of Africa’s population at the start of the 20th century, Africa’s population at the close of the 21st century is expected to be six times larger than Europe’s population.

Another noteworthy change concerns the proportion of the world’s population in Asia. Since the start of the 20th century, the proportion of the world’s population residing in Asia has been close to 60 percent. By the close of the 21st century, however, that proportion is projected to decline substantially to 45%.

The proportions of the world’s population residing in the remaiing three major regions have been comparatively stable and have remained in single digits. The proportions for Latin America and the Caribbean, Northern America and Oceania are approximately 8%, 5% and 1%, respectively.

The primary reason for the changing distribution of the world’s population has to do with the differences in the growth rates of the national populations residing in those major geographic regions. As a result of sustained rates of below replacement fertility in more than half of all countries, the populations of more than sixty countries have already peaked and are now facing demographic decline.

At the same time that many countries are experiencing below replacement fertility and facing population decline, many other countries, primarily developing countries in Africa and Asia, have relatively high fertility rates. Those high fertility rates are resulting in rapid rates of growth for their respective national populations.

In addition to the changing geographic distribution of the world’s population across regions, the rank of the twelve largest country populations is also continuing to undergo change due to considerable differences in demographic growth rates (Table 2).

Source: United Nations.

Two countries that are experiencing particularly rapid population growth are the Democratic Republic of the Congo (DRC) and Nigeria. With the DRC and Nigeria having total fertility rates of about five and six births per woman, respectively, their populations have increased rapidly.

The DRC’s population of about 12 million in 1950 increased to 51 million by the year 2000, a fourfold increase, and to 109 million by 2025, a ninefold increase over the 75-year period. Similarly, Nigeria’s population of about 37 million in 1950 increased to nearly 130 million by the close of the 20th century and to 238 million by 2025.

Furthermore, the population of the DRC is projected to increase to 431 million by the close of the 21st century, which is more than thirty-five times greater than the size of its population in 1950 and would make the DRC the fifth largest country in the world by the year 2100. Similarly, Nigeria’s population is projected to increase to 477 million, which would make it the fourth largest country in the world at the close of the 21st century.

In contrast to the rapid growth of the high fertility countries like the DRC and Nigeria, some of the largest populations in 1950, such as Germany, Italy, Japan and Russia, have grown relatively slowly during the recent past.

Due to sustained rates of fertility below the replacement level of two births per woman, those countries are among the many that are expected to experience population decline during the 21st century. In addition, after approximately four or five decades, the populations of Italy and Japan are expected to be smaller than they were in 1950 (Figure 2).

Source: United Nations.

Also, China’s population, which was 544 million in 1950, is projected to experience significant population decline during the 21st century. The population of China is expected to fall from a high of about 1.43 billion in 2020 to approximately 633 million by the year 2100.

In contrast to China, India’s population is continuing to increase. In 2022, India’s growing population overtook China to become the world’s largest national population. Furthermore, India’s current population of nearly 1.5 billion is expected to peak at 1.7 billion around 2060 and then decline back down to 1.5 billion by the close of the century.

The populations of some countries, such as Australia, Canada and the United States, are relying on international migration for the continuation of their population growth. However, without immigration and with their fertility rates below replacement levels, those traditional immigration countries are also projected to experience declines in the size of their populations.

Even with continuing immigration, the growth rates of the populations of those countries are comparatively modest. The United States, for example, is projected to increase from about 347 million to 421 million by 2100, which is an increase of about 20 percent. Despite that increase, the rank of the US population among countries is expected to decline from the third largest in 2025 to the sixth largest in the world at the century’s close.

As described above, the significant changes in the geographic distribution of the world’s population across the planet and the ranking in the size of country populations that occurred during the 20th century are expected to continue throughout the 21st century. Those ongoing changes have enormous economic, political, social and environmental consequences.

Fully recognizing and understanding the changes in the geographic distribution of the world’s billions of people among regions and the ranking in the size of country populations will substantially increase the chances of properly and successfully addressing the many resulting challenging consequences.

Joseph Chamie is a consulting demographer, a former director of the United Nations Population Division and author of numerous publications on population issues, including his recent book, "Population Levels, Trends, and Differentials".

© Inter Press Service (2025) — All Rights Reserved. Original source: Inter Press Service