So, in honor of Al Gore's 2007 Nobel Peace Prize for his work promoting awareness of climate change, a few very pretty maps illustrating the comparatively mitigating effects of high density urban settlement patterns on greenhouse gas emissions. Courtesy of Chicago's very own Center for Neighborhood Technology, it turns out, not too surprisingly, that city living -- as opposed to the suburban alternative -- is a much more efficient way of life, and generates fewer CO2 emissions per household. Compared to the suburban alternative, it's good for the planet.
Here are two contrasting maps illustrating auto-generated CO2 emissions for the city of Chicago. In the classical view, to the left, cities are shown to emit more aggregate emissions per square mile. If we take the measure of auto-generated CO2 at the household level, however, a very different picture emerges.
The older, denser areas of Chicago emit far less CO2 per household, chiefly due to lower automobile usage. The reverse relation holds in further out, suburban areas, where lower household densities generate greater amounts of greenhouse gas.
The same relation is found in places one might not expect, like Los Angeles, which is becoming increasingly dense overall, and especially in certain areas.
Or here, San Francisco:
It's useful to keep in mind that this has nothing to do with parks or parklands, and that the 19th century notion of parks -- famously expressed by Olmsted -- as the "lungs of the city" here plays no role. Their value in a city is of a different measure, and is important, but does not diminish the importance of urban density as a more highly efficient mode of life.