Urban sprawl detrimental to public health
Dr. Trevor Hancock
19 November 2017
Urban sprawl has to be one of the more damaging things we have done to the Earth – and to ourselves. That was not self-evident at the time it started in the 19th century, but it has been known for several decades, and yet we still are building sprawl. What’s more, we are exporting this destructive form of development to middle and low-income countries.
The limiting factor that kept cities compact for most of civilisation was how far one could reasonably travel and get back in a day. In the days when walking and horse transport – if you could afford one – were the only means of travel, that was not very far. But the advent of railways in the 19th century, followed by trams and buses, meant that people could live further away, and suburbs could develop.
This process began in London with the opening of the Metropolitan Railway in the 1860’s and London’s suburbs developed rapidly with the promise of country life in the city. But it really took off in North America with the advent of the automobile, leading to the car-dependent low-density urban sprawl we see today.
In a 2014 report for the Canadian Council on Urbanism, using 2011 census data, David Gordon and Isaac Shirokoff noted that “Canada is a suburban nation. Two thirds of our country’s population lives in suburbs” – and that rises to 80 percent in the largest metropolitan areas such as Vancouver. Moreover, they found that 90 percent of the population growth in metropolitan areas between 2006 and 2011 occurred in auto dependent suburbs and exurban areas, rather than in central cores or ‘transit suburbs’.
But why is that such a problem for the Earth and for us? The problem is that suburbs are very energy-inefficient and resouce intensive. Low-density housing makes public transport difficult, if not impossible, because there are too few people and it is too expensive. So everyone ends up driving. A 2008 Statistics Canada report, using data from the 2001 census, found that “the farther people live from the city centre, the more time they spend behind the wheel” – and they use a car more often and drive further.
Suburbs are also a problem because single-family dwellings are generally less energy-efficient than apartments or other forms of multi-family dwelling (although older houses in the urban core may be a problem because they have less insulation). And it is more expensive per person to provide infrastructure such as roads, water, sewers and electricity.
The result is that greenhouse gas (GHG) emissions – and other air pollutants due to transportation– are much higher in the suburbs. For example, a 2007 article by Jared VandeWeghe and Christopher Kennedy (the latter now Director of the new civil engineering program at UVic) looked at total residential GHG emissions in Toronto. They found the top ten census tracts, all in the suburbs, have an average annual emission rate almost 4 times that of the bottom ten (9 of them in the central core), largely due to vehicle emissions.
The health impacts of urban sprawl were first explored in depth more than a decade ago in the 2004 book Urban Sprawl and Public Health (one of the three authors, Larry Frank, holds the Bombardier Chair in Sustainable Transportation at UBC). While the health problems related to global warming caused by GHG emissions are global in nature, we certainly are beginning to experience health problems in Canada, and they identified many other health problems of a more local nature resulting from urban sprawl.
These include higher rates of physical inactivity and obesity due to driving rather than active transportation; respiratory and cardiovascular disease due to air pollution; more traffic injuries and deaths resulting from car-dominated transportation; and impacts on mental health and social wellbeing.
In short, continued suburban sprawl is incompatible with the overall health of this and future generations. The answer is obvious, although not simple: Stop suburban sprawl. In Victoria, that means intensifying the more central areas while preventing further suburban development in the Western communities or the Saanich peninsula. It also means holding the line against the further extension of water supply to be the Juan de Fuca electoral district, which is just a cloak for further suburban development.
© Trevor Hancock, 2017