Globally, it’s estimated that about a quarter of the world’s population is aged under 15, a significant fall from 38% in the early 1960s. Meanwhile, around 10% are now aged 65 or over, double the proportion 60 years ago. Overall, the world’s population is ageing, as advances in health lower infant mortality and allow people to live longer, but under-15s still currently outnumber those aged 65 and over by a ratio of about 2.5:1.
But this pattern isn’t the same across the world. Data from GlobalData Cities database shows that in many cities of North America, the two age segments are about equal, while in some cities in Western Europe and Japan, old people actually outnumber the young.
On the other hand, in some of the largest cities in Africa, children outnumber those aged 65 and over by a ratio of over 20:1.
Use the interactive map to explore the age demographic of populations of cities around the world.
Which city has the oldest population?
Japan’s high life expectancy and low birth rate mean it leads the world in the highest proportion of older people, in four of its cities (with a total population of one million or more), over 30% of the population is aged 65 or older.
The city with the world’s largest number of old people is the Tokyo Kanto Metropolitan Area, Japan, which is home to 8.7 million aged 65 and older, who make up 23% of the city’s population. It’s followed by Osaka, Japan, which has a population of 4.7 million people aged 65 and older.
Sapporo, Japan, the city with the second-highest proportion of those aged 65 and older, has seen a huge growth in its older population in the past two decades – in 2000 the demographic made up less than one-fifth of the population; in 2019 (the most recent data available), they made up 32%. In the same time period, Sapporo's population aged under 15 has decreased by three percentage points.
In Busan, South Korea, although the 65+ age group is smaller at a fifth of the population, it has seen huge growth, up from just 6% of the population in 2000. The population of under-15s meanwhile has fallen by eight percentage points, as the birth rate continues to decline.
Asian cities command the top 20 global cities, which have seen the biggest growth in those aged 65 and older since 2000. The first non-Asian city on the list is Tuscon, Arizona, in the US, followed by Belem, Brazil.
Which city has the youngest population?
In other parts of the world, there is a large and growing population of children.
In Lagos, the largest city in Nigeria, the number of children numbers over five million, and GlobalData forecasts will reach 6.2 million by 2030.
In Kampala, the capital of Uganda, under-15s make up almost half of the city's population, though the birth rate is declining while life expectancy increases, shifting the balance.
In Lilongwe, Malawi, under-15s now make up 44% of the population, an increase of six percentage points since 2000.
Poland and Germany have also seen significant growth in the proportion of their populations aged under 15 in their major and mid-size cities, as the population, particular working-age people, migrate away from the rural areas.
The data used in this piece is from the GlobalData Cities Database, collated from a variety of sources. The look-up table below can be used to explore when the most recent data was collected, and find more detailed description of the metropolitan areas covered.
[Read more: How is an ageing population changing urban Britain?]