This aerial view of Hanoi, Vietnam, clearly shows areas of decreasing density between the city and the countryside, making it hard to define the limits of the "urban" area.
In everyday usage, terms related to human settlements have vague, shifting meanings. What one person might describe as a small ‘city’ might be a ‘town’ or ‘village’ for someone else; one person’s ‘megacity’ might be a cluster of cities from a different perspective. Similarly, we can usually identify areas that are clearly within a city and others that are outside it, but there is usually a peri-urban area of intermediate density that usually lies between the two, making it hard to define a clear city limit. Formal administrative boundaries may have historic or political meaning, but are rarely aligned with the physical or economic extents of the urban area.
What exactly is a city? It depends who you ask
It turns out there is no standard international definition of an ‘urban’ area or ‘urban’ population. Each country has its own definition, and collects data accordingly. The statistic that 50% of the world’s population is urban is arrived at simply by adding up these incomparable, and sometimes conflicting, definitions.
When we think of urban expansion in the 21st century, we often think of ‘sprawl’, a term that calls to mind low-density, car-oriented suburban growth, perhaps made up of single-family homes. Past studies have suggested that historically, cities around the world are becoming less dense as they grow, which has prompted worries about the environmental impacts of excess land consumption and automobile dependency. A widely cited rule of thumb is that as the population of a city doubles, its built area triples. But our new study on urban expansion in East Asia has yielded some surprising findings that are making us rethink this assumption of declining urban densities everywhere.
- population growth
- sustainable urbanization
- East Asia urban expansion
- population density
- Urban Development
- East Asia and Pacific
- Lao People's Democratic Republic
- Taiwan, China
- Korea, Democratic People's Republic of
- Korea, Republic of
After the post was vacant for more than a year, Jennifer Keesmaat started this month as the Chief Planner for the City of Toronto. One of the first things she did was write an excellent article in the local newspaper arguing ‘our cities will define our future’. She makes the case for Toronto – but the same argument can be made globally and even more strongly for cities like Jakarta, Lagos, Sao Paulo, Belo Horizonte, Nanjing and Kunming. We are truly in the thick of the Urban Century; we are building cities at a faster rate than ever before, and increasingly these cities are defining our and our children’s future.
The strength of a country, and especially the strength of a city, is its ability to react to, and repair, the social fissures that originate wherever three or more humans live together. Social tectonics is the natural fracturing along societal lines like wealth, education, ethnicity, religion, sexual orientation, even color of skin, shapes of noses, or sports team preferences. Humans are amazingly adept at finding things in others to be wary of.
Social tectonics is active everywhere. No government or leader can stop it – but much can be done to reinforce our societies, institutions and cities, as well as reducing stresses. Like observant seismologists, social scientists sense where stresses are increasing and approaching breaking points. For example, the Occupy Movement that has popped up in many American cities represents growing stress in people who see too much concentration of wealth. The Arab Spring is a fracture between the general populace and the few who concentrated political power.
The climate, energy and resource challenges facing the planet are daunting. The world’s population continues to grow rapidly, and the majority of people now live in cities. While cities are projected to be home to nearly 70% of our population by 2050, this won’t happen unless society drives significant efficiency gains in all aspects of resource use. Leveraging information will lie at the heart of optimizing resource use.
While projections for city growth are common, we need ask ourselves a simple question -- how much longer will cities be able to service increasing demands for energy, transportation, water, and food without a wholesale transition in the way resources are managed? If we are going to accommodate billions of new urbanites, they will need energy for lights, for heating, for cooling; energy for transportation, housing and emergency services; energy for water systems and sanitation.