

I am surprised, although maybe I shouldn't be, by how quickly many seem to be allegedly turning their back on cities. According to the New York Times, cities were "losing their allure" well before this pandemic, and this might just be the tipping point. The underlying argument: Density is bad. We should probably all move somewhere bucolic, where the cost of housing is less and work isn't so stressful. Zoom only when necessary.
But as the chief economist for Indeed, Jed Kolko, rightly points out in the article, how people behave (and think) during a global pandemic is probably not a great indicator for how they will want to live their lives when this is all over. It's also not clear that urban density is really the contributor of spread. Hyper-dense cities such as Seoul and Hong Kong have been performing relatively well. (Joe Cortright has some thoughts on this.)
Once we get to the other side, we will see the data and we will get a better understanding of this current situation. And then in hindsight, we will find ways to rationalize the outcomes to ourselves. In the interim, I'm not about to bet against cities. Here's how Paul Romer, professor at New York University, put it in this recent interview in City Journal:
"I think the underlying economic reality is that there is tremendous economic value in interacting with people and sharing ideas. There’s still a lot to be gained from interaction in close physical proximity because such interaction is a large part of how we establish trust. So I think that, for the rest of my life, cities are going to continue to be where the action is."


Since 2012, a team at New York University has been working on something called the Atlas of Urban Expansion. What they are doing is collecting and analyzing data related to the quantity and quality of urban growth around the world. Everything from population densities to how well the streets were laid out during each geographic expansion.
The Atlas defines a city as having at least 100,000 people, which is a commonly used benchmark. According to this definition, there were 4,245 cities on the planet as of 2010. Included in their study is a representative sample of 200 of them, all of which can be found here.
They are also, rightly, looking at each city in terms of its extrema tectorum -- the limits of its built-up area. This is as opposed to using administrative boundaries, which wouldn't be as relevant in a study like this.
I really like the animations that they created depicting urban growth from 1800 to 2014, because they show: (1) where each city started (the dark nucleus); (2) how different urban shapes emerge as a result of geography, transport, and other factors; and (3) how land consumptive many of our cities have become in recent years.
Image: Atlas of Urban Expansion


Alain Bertaud has a new book coming out later this year from MIT Press called, Order without Design: How Markets Shape Cities. If you’re based or happen to be in New York, there’s a book launch on Tuesday, December 11, 2018 at NYU. You can RSVP here.
The book argues that, “operational urban planning can be improved by the application of the tools of urban economics to the design of regulations and infrastructure.” I haven’t read it yet and it’s not available until December, but I’ve just added it to my reading list.
I am of the opinion that none of us involved in the built environment should be working in insolation, without some understanding of the myriad of other forces shaping our cities. Cities are too complex and important for narrow views.
From what I’ve read about this book, it subscribes to that philosophy. And so I’m giving it a place in the queue.
Image: NYU