City rankings can be problematic—but they can also be useful. Our first of two pieces pieces about a new survey, with a focus on land use and transit.
I may as well start with the caveat that any attempt to measure, score, or rank places with respect to almost anything will be incomplete at best and can be wildly misleading at worst. First, rating systems tend to assign numerical grades to things that are partially or entirely subjective. Which city has the "best" transit service is not just a matter of coverage and service frequency, for example, but also of passenger comfort, convenience for riders' destinations (which vary from one to another), and whether the door-to-door experience feels safe, among other things.
Second, even measurements based on quantitative data are complicated. A rating of a city as "highly walkable" because of a large number of conveniences available within a short distance to a large number of people may mask that its sidewalks are actually in poor repair and poorly lit. So does one need to calculate measures (or proxy measures) of such factors? And then there's the whole matter of definition, since a "city" defined by an antiquated municipal boundary won't be the same as a city defined by actual patterns of settlement and employment (see image of Atlanta, left). And so on.
That said, such ratings and rankings are fun, because they start conversations about what is important. And they can be useful, especially if the authors spend some time describing the particular characteristics that cause a place to be evaluated favorably or unfavorably.
So, with that out of the way, let's get to the findings of a new study of 27 large American and Canadian cities by the Economist Intelligence Unit, conducted for the global corporate giant Siemens. By the Unit's evaluation, the top cities in their "Green City Index" were these:
- San Francisco
- New York City
The least green, starting with the lowest rated, were these:
- St. Louis
The top four certainly offer no surprises; few people would quibble with finding them in a top ten, certainly, in some order or other. I suppose one could quarrel with Denver at number five, but it isn't shocking to see it there. The bottom five already make me wonder about the criteria, though, since four of them are Rust Belt cities that, though economically distressed, may include populations whose living habits produce relatively small environmental footprints compared with those of, say, sprawling Charlotte or Dallas.
(In the interest of disclosure, I should note that I am an advisory board member and a longtime content contributor to the Sustainable Cities Collective, which is supported by Siemens. In addition, two of my very good personal and professional friends served on the expert advisory panel for this report. And NRDC hosts our own evaluation of city best practices on our Smarter Cities web site. All that said, I learned about this study and report only through the media.)
Most of the largest cities in the two countries were part of the study but some big names were not: Baltimore, Milwaukee, Salt Lake City, San Diego, Austin, Cincinnati, Kansas City, and New Orleans, for example.
The overall ratings are based on composite numerical scores derived from ratings for the separate categories of carbon dioxide, energy, land use, buildings, transport, water, waste, air, and environmental governance. While Siemens deserves credit for taking on the issue of urban sustainability and studying some very important factors, one can already see some issues: Couldn't one say that CO2, energy and buildings all look at the same thing, more or less? Where are health and fitness? Don't parks deserve their own category (instead of being lumped into land use)? Looking at a report where Charlotte ranks in the top 10 for land use while Pittsburgh is nineteenth, for example, makes one question the criteria.
Speaking of which, I'll devote the rest of today's post to the study's findings with respect to land use and transportation, categories of particular interest to many of my readers.
Here are your top five for land use:
- New York City
Bottom five, starting with the worst:
- St. Louis
Charlotte, Calgary, and Miami significantly outranked Seattle, Chicago, and Toronto for land use. Even Houston ranked in the top half. Really?
As it turns out, the scoring of each city was based on four equally weighted factors, two of which were calculated from reported data (percentage of protected green space as a portion of total land area, and population density)—and two of which were scored according to expert judgment (green land use policies such as tree planting, and policies for containment of sprawl). I suspect that the Rust Belt cities, which have lost inner-city population, may have been disadvantaged in the population density measurement if the researchers looked only within the municipal limits of the central city. That's unfortunate.