Urban environments can be dense in many different ways. This is a topic that we have discussed on several occasions here on the blog. But this working paper by Solly Angel, Patrick Lamson-Hall, and Zeltia Gonzales Blanco -- called The Anatomy of Density -- is a more scientific way of looking at it. They have come up with six measurable factors that, when combined, define urban density.
What this means is that cities achieve urban density through different kinds of built form. Hong Kong, for example, gets its density from height, even though only about 4% of its land area is occupied by residential buildings. Dhaka, on the other hand, does it through low building heights and high residential coverage. Homes occupy about 20% of the city's area. Another dimension is crowding.
But here's something that may surprise you. Most cities are actually becoming less densely populated. And, despite our best efforts to encourage more sustainable forms of development, sprawl has continued to outpace densification in the vast majority of the urban agglomerations that were studied as part of this working paper. The wealthier we become, the more space we want to consume.
Here's a graph from The Economist that speaks to this trend:
Without a question, we are living in an urban era. More people now live in cities than anywhere else on the planet and I’ve repeatedly argued that cities are our most important economic engine. As a result of these demographic and economic shifts, we’re seeing megacities at a scale the world has never seen before. Below is a list of the top 35 largest urban areas in the world.
The top urban area is Tokyo-Yokohama, with a population of roughly 37.5 million people. That’s almost the same as the state of California and is more than the entire population of Canada, which sits at just over 35 million people. London, which, during the 2nd half of the 19th century, would have been the largest urban area in the world is now the 29th largest.
But at the same time, London arguably remains the most important global city–a title that can only really be rivalled by New York. Which raises an important distinction. One that Aaron Renn clearly identifies in this recent article for New Geography: Just because a city is a megacity, doesn’t mean it is or will ever be a global city. In fact, Renn argues that many of the world’s largest megacities will never “turn the corner” and become leaders of the global economy.
