Via Good, Physorg reports on a recent paper: City dwellers produce as much CO2 as countryside people do: study:
"Most previous studies have indicated that people in cities have a smaller carbon footprint than people who live in the country. By using more complex methods of analysis than in the past, scientists at Aalto University in Finland have discovered that people's carbon emissions are practically the same in the city and in the rural areas. More than anything else, CO2 emissions that cause climate change are dependent upon how much goods and services people consume, not where they live."
Full article Jukka Heinonen and Seppo Junnila (2011) Implications of urban structure on carbon consumption in metropolitan areas Environ. Res. Lett. 6 (January-March 2011) 014018
If you buy Life-Cycle Analysis, this is one strike against sanctimonious urbanites in the GHG blame game.