Here’s a chart that almost speaks for itself:  sprawling cities require more driving—and hence, produce more CO2 from cars and trucks—than do compact cities.

Density and Driving


The chart is from a new study in the journal Environmental Science and Technology, comparing greenhouse gas emissions in 10 global cities.  The lessons are pretty clear:  compact cities in temperate climates, powered by low-carbon electricity, are the ones with the lowest carbon emissions.  It seems pretty obvious—but sometimes you need a bunch of fancy math to teach you what you already know.