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(James Cheshire and Michael Batty, UCL) California, 23 November (The Conversation). On 15 November 2022, a baby girl was born at the Dr. Jose Fabela Memorial Hospital in Manila, Philippines, named Vinis Mabansag and symbolically considered the world’s eight billionth person. Of these eight billion people, 60 percent live in some town or city.
By the end of the 21st century, 85 percent of Earth’s estimated 10 billion people will live in cities. Cities do not grow only by the number of inhabitants. The more people they host, the more services they need (public transport, energy infrastructure, water supply), the more systems they need and the more resilient their economies have to be.
It may come as a surprise to learn that there really is no single definition of what a city is. In medieval times, cities from London to Seoul were delineated by their walls. And even in the 20th century, the idea of city limits still persists.
Today, if the process of urbanization still brings to mind the largest metropolises from before the millennium (Tokyo, São Paulo, New York or Mumbai), they still represent a decreasing proportion of all the world’s cities. In contrast, in more rapidly growing urban centres, such as Lagos, the geographic limits of a mayor’s official jurisdiction often expire long before the population. Meanwhile, its economy is often deeply intertwined with that of neighboring cities.
Where to draw the line between what is a city and what is not – it is becoming increasingly difficult to answer the question of where one city ends and another begins. As the world moves towards greater urbanisation, settlements are expanding into what urbanists call ‘megalopolis’, merging with each other. The largest of these mega-cities is home to more than six crore people. The term megalopolis was used by Jean Goitman in 1967 to refer to large metropolises. It is also called Megapolis. Both words are of Greek language which means – great. It is used in geography and other subjects.
In China, the area in Guangdong Province around the mouth of the Pearl River, now known as the Greater Bay Area, effectively includes 11 cities from Macao to Guangzhou, Shenzhen and Hong Kong. With a total population of over 70 million inhabitants, it is two million more than the entire population of the UK, which occupies about a fifth of its total area.
In economic terms, it is just as large: with US$1.64 billion in 2018, its GDP represents 11.6 percent of China’s total GDP. Meanwhile, on the West African coast, the 600km distance between Abidjan, Ivory Coast and Lagos in Nigeria is shrinking rapidly. Experts estimate that by 2100, this cluster of nine cities will be the most densely populated on Earth, with 500 million people.
It wasn’t until the mid-18th century that cities really began to grow when we started building machines that would move us much faster—and further—than any technology ever invented. For the first time, cities, and London in particular, broke the limit of around one million people in size that had hitherto dominated the urban world. Some cities, including Chicago and New York, soared upward as the technologies of the steel frame and elevator enabled them to erect the earliest skyscrapers, those cathedrals of commerce, with the help of resources.
With the invention of the automobile, many cities such as Los Angeles grew outward, despite widespread resistance to the idea of urban sprawl. Some large cities in the developing world have moved inward, including Dar es Salaam in Tanzania or Nairobi in Kenya. Here, the idea of a compact city based on public transport and high residential density has taken root.
Most people today live in medium-sized or small cities. We are still largely dependent on vehicles for various activities, usually commuting between home and work. However, over the past 50 years, the advent of computers and networked communications has meant that people can now live far away from their partners. It blurs the physical boundaries of any city.
Counting a city’s inhabitants and mapping its geographic boundaries are only some of the aspects considered when defining what a city is. The digital layer that now covers the planet enables citizens of any city to interact with anyone and everyone at any time, in any place.
Cities will continue to grow and change physically. By the end of the 21st century, there will undoubtedly be some form of city everywhere, but the term itself is unlikely to disappear. Rather its meaning will change. In 1937, in a collection entitled The City Reader, historian Lewis Mumford had already stated that cities, however recognizable as physical entities, would be places of social interaction of communication.
Scholars agree that as cities grow larger, they generate economies of scale that increasingly dominate their economic growth and prosperity. Evidence suggests that the urban world is even more complex. The emerging urban world is very different from the earlier world. Attempts to determine the physical boundaries of the city remain important. However, in figuring out how to calculate with this new complexity, it can be very superficial.
