Monday, December 27, 2010

The environmental impact of cities

In preparing for the course I will be teaching with a few other graduate students next semester, I have been reading a lot about the changing landscapes of urban areas. Some urban areas have declined (but are now being reborn) significantly, such as areas in the US Midwest (Detroit, Cleveland, Youngstown, Buffalo), some have been well bounded from the outset (Portland), and others (New York) have continued to grow in population. By 2050, half of the world's population will reside in urban areas. There is a line of thinking, from an environmental standpoint, that concentrating residents in urban environments allows for a more efficient use of resources - energy, water and electricity can all be used more efficiently.

This is a continuation of a previous post on cities - I started thinking about cities again because I am visiting my sister in New York City; she lives in Manhattan and is a fashion designer. In an article in the New Yorker from 2006, David Owen explains why everywhere should be more like New York. Manhattan is a place where you can have multi-million square foot buildings, with tens of thousands of people working in them, with per capita use of energy being much lower than in more decentralised and sprawled urban environments. Mass transit can be used to move scores of people with the same reasoning. What is interesting, however, is the emphasis in the article on energy. (In fact, many people narrowly think that the bulk of the environmental problem today is about energy.) What is not talked much about, which Bettencourt and West from the Santa Fe Institute point out, which is evident when you visit most any urban environment in the US, is the confluence of money and ideas from elsewhere. Ideas can include culture, food, drink, art and music. When you combine multicultural resources with people who have the ability to consume those resources, you have added a whole new layer to the environmental impacts of cities. This struck me when I went inside Eataly, a 50,000 square foot complex that cooks and sells everything Italian. 

I am not going to lie - I eat Italian food, and I love food from all over the world. But it is important to recognise the environmental costs of doing so. (Sam has, and she has gone local. Since I have been buying unpackaged foods, I have also been eating almost exclusively locally-grown foods.) Cities have now become dependent on other cities to provide resources for consumption, and therefore the impacts of the city are no longer contained to the region that the city exists in. This is a key feature of globalisation. Cities now have huge ecological footprints. A study by Folke et al. shows that large cities in the Baltic region of Northern Europe require inputs from land areas between 500-1100 times the land areas of the cities themselves. How do we reconcile growing and rejuvenating urban environments with diversity and environmental impact?


  1. "Cities now have huge ecological footprints."

    Well, yes, but mainly because they have more people.

    As with energy usage, you want measures of environmental impact *per capita*, yes?

  2. Bruce, yes, you are right. But I also meant that because of connections of cultures, as well as increased resources for the consumption of those cultures, ecological impacts are probably much larger than we think they are, and of course, incredibly difficult to measure...

    And yes, per capita.

    Also, if you by any chance know how much trash people generate per capita depending on which city they live in, or have a link to something like that, please let me know. That'd be great!