The planet is going to need a lot more room for cities and suburbs. The Lincoln Institutes’s report on “Making Room for a Planet of Cities” illustrates this vividly. The report examines where and how quickly cities have and will grow in the past, present, and future.
One of the most interesting findings is that cities all around the world are becoming less dense. In fact, average global urban densities peaked in 1894! Densities have been falling for a very long time, and many decades before the car really began to dominate.
However, not only are densities falling, but cities are growing. Almost three billion people are expected to move to cities by 2050, doubling the number of people in cities globally.
The Lincoln Institute estimates that anywhere between an extra 600,000 to 2.6 million square kilometres of land will be urbanized by 2050, up from 600,000 square kilometres today.
Looking at those numbers and the history of urban growth the authors conclude that because so many global cities are growing very quickly, growth boundaries, like green belts, are a bad idea. They may work in the rich and slower growing places, but in regions where the population of cities is expected to double and triple they make no sense. Greenbelts would only make sprawl worse by forcing people to move outside the green belt creating a city that would sprawl even more.
One surprising recommendations for a Toronto reader to note is that the authors suggests that Toronto, a city with one of the largest greenbelts in North America, is a model for responsible sprawl because the city has grown along a regular grid of arterial streets. The report says:
For an arterial grid to function as the road network for a public transport system three conditions must hold: (1) residential densities must be sufficiently high to sustain public transport; (2) the roads need to be spaced not more than one kilometer apart, so the great majority of people can walk to a bus stop from any location in less than 10 minutes,… and (3) the width of the rights-of-way for the roads needs to be on the order of 20–30 meters.
Toronto is one city that has been able to build and maintain an effective public transportation system that extends along an arterial road grid far into the suburbs, and it now boasts the third-largest transit system in North America
Toronto a model for global suburban growth? What do you think?