David Satterthwaite argues that the oft-repeated claim that cities generate three quarters of the world’s greenhouse gas emissions is just plain wrong. Writing in the current issue of the journal Environment and Urbanization, he charts what sounds a lot like one of those oft-repeated urban legends:

Perhaps this was an estimate for the United States, which was then assumed to be valid worldwide. However, these figures are certainly inaccurate when applied to cities worldwide, although it is difficult to produce an accurate figure because there are too few cities for which there are detailed greenhouse gas emission inventories.

Sorting out what is city and what not is also a definitional issue. Should my city’s tally include the emissions from the farm outside of town where my food is grown?

[I]f greenhouse gas emissions from power stations and industries are assigned to the location of the person or institution who consumes them (rather than where they are produced), cities would account for a higher proportion of total emissions. But it would be misleading to attribute this to “cities” in general, since these emissions would be heavily concentrated in cities in high-income nations and they should be ascribed to the individuals and institutions whose consumption generates them, not to the places where they are located.