Major changes in the world’s population through 2100

Jorge Costa Oliveira

The highly regarded Pew Research Center recently released a concise analysis of projections for some of the major changes in the world’s population through 2100, based on the United Nations’ 2024 Revision of the World Population Prospects.
First, it is worth recalling that the world’s population has grown exponentially over the past 125 years, more than tripling in the last 75 years.

The UN projects global population growth of 1.9 billion, peaking at 10.3 billion in 2084 and declining slightly to 10.2 billion by the end of the century.

However, some revised projections put the peak earlier – in 2064 (IHME), 2070 (IIASA), or as soon as 2050 under the UN’s low-fertility scenario. This will be the first time since the Black Death (1343–1353) that the Earth’s population has declined – not due to a linear growth of the food supply or other resources (Malthusianism), but rather due to people’s life choices.

The three most populous countries in 2025 – India (about 1.5 billion today), China (1.45 billion), and the U.S. (347 million) – will follow very different trajectories. India’s population is expected to peak at 1.7 billion in 2061, then decline to 1.5 billion by 2100. China’s population, which began shrinking in 2022, is projected to fall to 633 million in 2100. The U.S. population is expected to grow to 421 million by 2100.

Five countries will account for more than 60% of global population growth through 2100: the Democratic Republic of Congo, Ethiopia, Nigeria, Pakistan, and Tanzania. By 2100, Congo and Tanzania will join Nigeria and Ethiopia among the world’s 10 most populous countries. It should be noted that the only region expected to significantly increase its population through 2100 is Sub-Saharan Africa – from the current 1 billion to about 4 billion people.

The world’s population is set to age. The global median age is projected to rise to 42 years in 2100, compared with 31 today and 22 in 1950.

The number of people aged 65 and older is expected to more than double – from the current 857 million (10% of the world’s population) to 2.4 billion in 2100 (24%). By 2100, the ratio of people under 25 to those 65 and older will be 1:1; today, it is 4:1, and in 1950 it was 10:1. This shift reflects not only the rising number of older adults but also the expected decline in people under 25 – from today’s 3.3 billion to 2.9 billion in 2100 – due to falling fertility rates.

Africa will remain the world’s youngest region. Currently, the median age in Africa is 19, significantly lower than in any other region. It is expected to rise to 35 by 2100, but Africa will still be the youngest region. Today, Europe’s median age is 43 – making it the oldest region in the world – and it is expected to remain so.

Demography is one of the areas in which the world is changing, and it will look very different in just a few decades. Africans, Americans, Asians, and Europeans need to discuss this coming transformation and adjust their policies accordingly.

linkedin.com/in/jorgecostaoliveira