Recently I travelled to Montreal, and spent a lot of time walking through the city. There’s a particular style of houses that characterize Montreal’s residential downtown: long streets of duplex, row, and small apartment housing. This is what our mayor, Don Iveson, would call the “Missing Middle” (1), medium density housing that makes up the gap between single detached houses and skyscrapers. That’s not to say that Montreal is entirely made up of medium density residential zones - it has sprawling suburbs like most other North American cities. However, its downtown is a fantastic example of vibrant, affordable, and sustainable residential development.
As I discussed in the first part of this series, urban areas are major contributors to human-caused environmental damage when they are sprawling metropolises which use land and resources inefficiently, promote lengthy car-based transportation, and increase energy consumption. What if we increase the density people live in, decreasing the distance between residential and commercial areas, encouraging walking and transit use, and decreasing home prices? I had an eye-opening experience in Montreal, where I could walk a few blocks in any direction and have all the groceries, entertainment, and transit services I would need in daily life. Besides convenience, what does density do for a city’s environmental impact?
First of all, density increases the viability of alternate transportation options to cars. It makes transit services more efficient to provide (because of increased ridership per area) and reduces overall commute time, which promotes walking and cycling. Interestingly, according to the 2011 Canadian census, 29.2% of working Montrealers commute by transit, walking, or biking, while only 16.5% of working Edmontonians do so (2). As can be seen in the graph below, there is an inverse correlation between density and car use when comparing many major North American cities. Montreal is at the highest level of density and the lowest level of car usage among the cities studied.
Second, as outlined in William B. Meyer’s book The Environmental Advantages of Cities, there are economies of scale which occur when people live in close proximity to one another (3). This means that with increased density, the monetary/time/environmental costs of things like water treatment, waste disposal, and energy provision are reduced, since they can be done on a large scale over a smaller area.
Third, increased density reduces the amount of land needed to house the millions of people that may live in a city. When we live in close proximity to each other, or in houses stacked on top of one another, less natural land needs to be converted to support our living space. As Meyer states, “precisely by concentrating human impact, cities contain it” (3). The amount of wetlands, erosion-prone soils, and rare species’ habitat that is destroyed to house the human population is reduced when we live in dense, vibrant cities.
Next time, I’ll look into a final positive effect of density on the environment: the creation of tight-knit communities which affect positive change.
Have a great rest of the week, and enjoy the sun!
The Environmental Advantages of Cities: Countering Commonsense Antiurbanism, by William B. Meyer (2013)