Compact Cities Part 3 – Climate effect of “compact”-ness

Last week, we presented the case of Atlanta and Barcelona, part of the research of Mr. Alain Bertaud – cities with approximately the same population (1990) but one 20 times larger than the other in area. It's a good example of the concept of compact cities versus urban sprawl and its corresponding effect on the mobility of people and the cost associated with it, especially in terms of congestion.

Next, we look at the effect of both on climate change, and I will be drawing from the presentation of Mr. Sunny Kodukula, project coordinator, Wuppertal Institute for Climate, Energy and Environment, during the 11th Intergovernmental Regional Environmentally Sustainable Transport Forum in Asia. Using updated figures, Mr. Kodukula summarized: Atlanta - population = 5.25 million, urban area: 4,280 sq. km.; Barcelona - population: 5.33 million, urban area: 162 sq. km. Atlanta has 500,000 public transport trips/weekday. Barcelona has about 2.6 million trips/day, with 953 million boardings/year!

A lot of people will always react like, “you can't compare, the circumstances are different, they're from different backgrounds and cultures.” The conclusion laid out being that we can't do anything if our city is already a car-centric one. But the experience of Amsterdam in the Netherlands points out to the possibility of steering a city to a better future. We can discuss this in another article later, but there was a time when Amsterdam was not like Amsterdam today. The point is; we can change how our cities will be in the future, if we really want to.

And the effect on the environment might provide the impetus for the change. Mr. Kodukula gave us another startling comparison – on CO2 emissions from urban transport (public + private). Barcelona has 0.7 T CO2 /ha/yr. But Atlanta emits a whopping 7.5 T CO2 /ha/yr, or more than 10 times its comparative pair. And since Atlanta has a greater area, the disparity even becomes worse. It doesn't take much to connect where these emissions come from for after all, a big bulk of it comes from mobile sources. Meaning – transportation. And if your transportation mode is primarily by private cars with an average of 1.2 passengers each, you would readily see why the city with a highly functioning public transportation will result to lower emission levels. Per capita.

Whether we like it or not, there is a solid link between transportation and global warming, and there is direct link between transportation and the “compact”-ness of a city. A city where people live closer, and more evenly spread out, makes public transportation, as well as walking and cycling, even more advantageous and attractive to its residents. This is the reason why Bus Rapid Transits (BRTs) are considered environmentallysustainable modes and almost always placed side-by-side with walking and cycling. BRTs, when proposed and built, are always characterized by the amount of CO2 emission savings they generate. This further reinforces the connection between compact cities and climate change. (To be continued)