“A developed country is not a place where the poor have cars. It’s where the rich use public transportation.” -Mayor Gustavo Petro of Bogota, Columbia
As author Vishaan Chakrabarti discussed during Urban Green’s recent Author Talk on A Country of Cities, density and sustainability are inextricably linked. A successful mass transit system exists when investment bankers and fast-food workers ride the same subway because it is the most efficient way to get from Point A to Point B. This level of efficiency, however, is only possible with the population density to support it; only 4% of U.S. cities currently make the cut.1
Suburbanization has been a growing phenomenon since the 1940s, encouraged by rampant land development and various economic subsidies such as the federal mortgage interest deduction. As Chakrabarti notes, “people should be free to live in suburbs, but we shouldn’t pay them to do it.”
Research has shown that the mortgage interest deduction is unnecessary to promote home ownership and only increases the size of the homes purchased – further exacerbating environmental and financial strains through a larger per capita carbon footprint.
As expected, when urban density increases, innovation and GDP also rise. Did you know that 90% of the U.S. GDP is generated on 3% of our landmass? It makes you wonder, if our cities are such incredible engines of economic growth, why aren’t our schools palatial and our subways the most modern in the world? Chakrabarti says it’s because the surplus fruits of urban labor are dispersed among the suburbs. Therefore he emphasizes the importance of shifting subsidies away from suburban highways and mortgages for McMansions and instead funding mass transit, affordable housing, and urban schools. By holding on to a greater percentage of the GDP, cities can further invest in the resources and infrastructure necessary to be the best places to live while supporting a growing population.
So how do we build good cities? Hyperdensity, mass transit, walkability, parks, beautiful architecture, and affordable housing are good places to start. Chakrabarti notes that a good city requires hyperdensity (at least 30 dwelling units per acre) to provide ridership for mass transit such as subways or bus systems. In addition, greater investment in high-speed rail is essential to reduce emissions from increased plane travel. To put this in perspective, if the U.S. invested in high-speed rail on par with China (which has a similar landmass to the U.S.), we could travel from NYC to Atlanta in three hours – without taking off our shoes!
Hyperdensity does not necessarily mean a sea of skyscrapers; row houses and a mix of low and tall buildings can do the trick. As Treehugger’s Lloyd Alter notes, cities need to find a “Goldilocks density: dense enough to support vibrant main streets with retail and services for local needs, but not too high that people can’t take the stairs in a pinch.” While upzoning can in some cases enhance economic activity and neighborhood revitalization (e.g. the area surrounding the High Line), downzoning often raises prices and pushes low-income residents out to the suburbs. The challenge is to find the perfect mix – “not too high and not too low, but just right”.2
As all New Yorkers know, great cities generate a demand for housing that can make them expensive cities. In order to address these pervasive price increases, affordable housing must be a top priority. New York’s 80/20 housing program is one model; developments that set aside at least 20% of all units for low-income residents can receive tax-exempt financing. Modular housing is another affordable option that has gained traction in recent years. Coming in 2015, My Micro NY features 55 new micro-units in Manhattan, 40 percent of which will be affordable.
At the crux of these recommendations for thriving low-carbon cities lies the importance of shifting to a more sustainable way of life that people are happy to be a part of. As Chakrabarti says, “We should strive for a country of trains, towers and trees; not a country of highways, houses, and hedges.”
1 A Country of Cities, Vishaan Chakrabarti, May, 2013, p. 26
2 “Cities need Goldilocks housing density – not too high or low, but just right,” The Guardian, Lloyd Alter, April 16, 2014