Urbanization and the Megacity

Across the globe and in a short amount of time, we’ve given up the tractor for the city bus, the open landscape for one of brick and mortar. We are now an urban planet. In fact, by 2008 over 50 percent of the global population was living in urban areas. It was 3 percent in 1800. Throughout history, cities have attracted people as centers of culture, religion, learning, and economics. Looking back, the first wave of urban migration took place in what are today’s more developed countries, especially in Europe and North America. But looking ahead, 90 percent of the future urban increase is expected to take place in Asia and Africa, and it is projected that more than two-thirds of all people will be calling cities home by 2050.

Urbanization is often linked with economics – increased job opportunities, a centralized market, better pay and higher individual wealth have all drawn people into cities. And for a long time, these pull factors are what caused cities to grow. The Industrial Revolution caused a shift from agriculturally based societies to industrial, and thus geographically centered, societies. But that dynamic is changing. Today, most urban growth is natural increase – due to more births than deaths among those already dwelling in cities. Additionally, formerly small settlements are being reclassified as urban areas as the populace living there grows from within.

Implications of Growing “Too Fast”

Depending on cities’ ages and locations, there is much variation in wealth and infrastructure. Many of the newer urban areas, located in Latin America, Asia and Africa, have an entirely different look, feel, and outlook than their older European or North American counterparts. How fast an area grew, or is growing, is a key component.

When a city grows at a manageable rate, which is often considered roughly 1 percent annually, its infrastructure can keep pace with an increasing population and its demands. Necessities such as roads and public transportation, appropriate sewers and water treatment facilities, clinics, schools and housing have time to be planned and built alongside the increase in human numbers. The risk of fast urban growth, especially in an economically strained country, is that the necessary infrastructure often cannot expand fast enough to keep up with residents’ needs. Without infrastructures in place to provide basic needs, residents can be forced to create their own provisions with whatever is available.

The Rise of Slums

In less developed countries, densely populated slums form both on the edges and within the largest cities. Due to a poor economy and weak infrastructure, cities such as Mumbai, India do not have the means to support the overwhelming urban population. According to the 2018 UN World Urbanization Prospects Report, Mumbai ranked as the seventh largest city in the world, with 20 million people in the entire metropolitan area. Even more striking, over half of Mumbai’s metro residents live in slums surrounding the city, causing huge public health, environmental, and land use problems.

Slum dwellers survive with practically no sanitation, water, urban amenities, employment, or security, and roughly one-seventh of the world’s population lives under these conditions. The lack of running water and sanitation, plus malnutrition and inadequate housing, leads to deadly conditions in the slums and shantytowns that surround many cities in Africa, Asia, and Latin America. The spread of HIV/AIDS and other infectious diseases in areas where so many people live in such close physical proximity is a critical public health issue for urban areas throughout the developing world. When combined with high unemployment rates and inadequate schools, these public health issues create a poor quality of life for many of the city’s residents.

The Emergence of Megacities

The urban shift over time has led to the emergence of the megacity – a city with a population of 10 million or more. New York City and Tokyo were the first known megacities, both reaching an urban conglomeration of over 10 million by the 1950s. But today they are far from alone in their size. In 2018 there were 33 megacities across the planet – from Sao Paulo, Brazil to Lagos, Nigeria and London, England to Shanghai, China – and all major global regions except Oceania are marked with megacities.

Most of the cities that have reached the 10 million marker in recent years are located in Asia and Africa. In fact, it’s where six of the eight newest megacities can be found and where nine of the 10 projected 2030 megacities will be located. These regions are also home to the fastest growing megacities. The population of Kinshasa, capital of the Democratic Republic of the Congo, has doubled roughly every 5 years since 1950. From 2010 to 2015, Kinshasa’s population grew by over 23 percent, and today over half of the more than 13 million residents are under 22 years old. A combination of factors has led to this growth including migration from rural areas, high fertility rates, and widening of the city’s boundaries. The population is outpacing almost all support structures in the city where the threat of food shortages, traffic congestion, and insufficient education facilities have become a stark reality.

Environmental Pros and Cons

A large urban population may seem environmentally troublesome with cities viewed as a disruption to the natural world. But environmentalism and urbanization are not incompatible. Dense urban areas have a much smaller ecological footprint – many people live in apartments or smaller connected houses rather than ranch-style homes in sprawling neighborhoods. Multifamily dwellings have the added benefit of being more energy efficient and they require less resources per person. Cities are also walkable and have public transportation options that can make cars less of a necessity. And above all, densely populated areas make it possible to protect other open spaces to serve as wildlife habitat, farmland, conservation areas, or oxygen-producing forests.

But of course, there are ecological downsides to cities as well. Concentrations of people mean concentrations of pollutants and trash. Cities produce up to 70 percent of global CO2 emissions and smog is becoming a common feature in many urban landscapes. Large swaths of continuous pavement prevent water drainage and boost temperatures. Without proper infrastructure, cities also risk having waste – both trash and human waste – clogging waterways and causing damage. And with cities across the globe producing more than 2 billion tons of waste annually, that’s a lot for one area to handle.

Planning an Urban Future

It is predicted that most future urban growth will happen in settlements currently home to between 100,000 and 250,00 people, and if this is to be done sustainably, planning is a must. Future high-growth areas require strategic urban planning individually tailored to a city’s history, culture, value system, and other specificities; a single cookie-cutter approach won’t work, nor will the plans of the 20th century. But by keeping an eye towards social justice concerns, natural resource use, environmental hazards, and other issues of modern cities, urban plans can help ensure the health and well-being of tomorrow’s city dwellers.

distribution of world urban Population by area