Urban sprawl, that uncontrolled spread of city development into neighboring regions, is increasing exponentially. But the solution is not to build more high-rises. Simply put, the best solution is to use and re-use land sparingly.
That’s according to Concordia University geography professor Jochen Jaeger, co-author of a recent joint European Environment Agency / Federal Office for the Environment report called Urban Sprawl in Europe. “Before we can put a stop to urban sprawl, it’s important to understand how to reliably measure it,” says Montreal-based Jaegar. “To do that, we developed a metric called Weighted Urban Proliferation — or WUP. It takes into account how much of an area is built up, the spatial dispersion of the built-up areas, and how many people live or work in a given place.”
The analysis uses revised urban sprawl metrics. It takes into account the way built-up areas are laid out and how they are used. It also looks at the factors which contribute to an increase or decrease in urban sprawl. Not surprisingly, the results indicate that sprawl is most pronounced in wide rings around city centers, along large transport corridors, and along coastlines.
The Origins of Urban Sprawl
NYU Doctoral candidate, Thomas Laidley argues in a 2016 Contexts article that “economic and social turmoil in central cities—aided by a web of overtly racist, exclusionary housing policies—drove millions away from urban cores.” Support for the exodus included the construction of the interstate highway system, cheap energy, and reasonably financed housing in the suburbs via the GI Bill.
Long-distance commuting became convenient and affordable, so that the geographic extent of cities and towns rapidly expanded. So, too, did low-density residential housing, single-use zoning, and increased reliance on the private automobile for transportation. Residents made a trade-off, spending more time and money on transportation in exchange for cheaper housing.
Implications of Urban Sprawl on Carbon Dioxide Emissions
Carbon dioxide emissions are the main element of climate change. Areas of sprawl tend to produce more pollutants per person than those outside of sprawl. The most significant consequence of transportation as a by-product of sprawl is the automobile’s emissions. About 70% of greenhouse gas (GHG) emissions from transportation are from cars and trucks, and two-thirds are generated within urban areas.
For example, Atlanta’s sprawling layout requires residents to drive more often and farther distances to get around than New Yorkers, who can often walk or take public transportation to their destinations. People in areas like Atlanta have nearly twice the automobile carbon dioxide emissions per person than areas like New York.
And, by most measures, urban areas are still sprawling as they are built out or as their large cities depopulate. Thus, sprawl intensifies when people try to find affordable housing. Conversely, sprawl contributes to economic inequality in metropolitan areas. That’s because disparities emerge when people are sorted into low income housing areas or more elite, albeit compact regions, absent of the balancing effect of the residents who live in sprawled areas.
Planning Ahead to Avoid Additional Sprawl
Sprawl isn’t inevitable. It is often the result of poor planning and short-term goal-setting. The authors of Urban Sprawl in Europe suggest a combination of measures work best:
- Brownfield recycling: repurposing land previously used for industrial purposes, which has huge potential in cities with industrial pasts like Montreal;
- Careful population densification;
- Transit-oriented development through better coordination between transport ministries and cities;
- Stronger planning legislation.
These measures are often accompanied by a call to urban regional planning, in which civil engineering takes into account protecting natural and agricultural land, water bodies, and biodiversity. Such approaches might also take into account what Despommier described as “one that is based on natural processes and mimics the best that nature has to offer with respect to balance.”
Urban planning grounded in natural design? Sounds like a wonderful, if overdue goal to offset the effects of sprawl.
Photo credit: UrbanGrammar via Foter.com / CC BY-NC-SA