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Suburbs Emit More Carbon Dioxide than Cities - Study

Which municipalities and locations within the United States contribute the most to household greenhouse gas emissions? The answer is revealed in a new data crunching exercise conducted by academics at the University of California, Berkeley.

They confirmed that average household carbon emissions are loosely correlated with population density, rising in the suburbs but decreasing in inner-city areas where people use less individual motorised transport.

Suburbs alone account for half of total U.S. household carbon footprints, they say.

For example, Lower Manhattan has an average household carbon footprint of 32.5 tCO2e (tonnes of carbon dioxide equivalent) compared to Montclair Essex County, New Jersey where it rises to 68.3, more than double.

(Use the maps below to find out the emissions for every area in the United States. Hover over the map. Use controls at left to zoom and drag map to any location.)

This map displays average annual household energy carbon footprints for zip code tabulation areas.

Christopher Jones and Daniel M. Kammen of the Energy and Resources Group, Goldman School of Public Policy, and Department of Nuclear Engineering at the University used national household surveys and developed econometric models of demand for energy, transportation, food, goods and services to derive their figures.

They were assigned to U.S. zip codes, cities, counties, and metropolitan areas.

They write in their report that "We find consistently lower household carbon footprints in urban core cities (40 tCO2e) and higher carbon footprints in outlying suburbs (50 tCO2e)."

In the 50 largest metropolitan areas there is a range from between 25 and over 80 tCO2e in the 50 largest metropolitan areas.

In general, population density "exhibits a weak but positive correlation with household carbon footprints (HCF) until a density threshold is met, after which range, mean, and standard deviation of HCF decline", they say.

Population density contributes to relatively low HCF in the central cities of large metropolitan areas, but in the more extensive suburbanization in these regions it contributes to an overall net increase in HCF compared to smaller metropolitan areas.

The findings will be of great significance to planners.

Transportation Carbon Footprint

This map displays average annual household carbon footprint from transportation for zip code tabulation areas.
(Hover over the map to see underlying data. Use controls at left to zoom and drag map to any location.)

Using this data is quite clear that transportation provides one of the biggest factors in increasing household carbon footprints from living in the suburbs, because people are forced to use their cars more often. Often, living in is central area means that no car is needed.

Also contributing will be the fact that homes are generally smaller in cities anyway.

Using the Map Data
 The study will be published in science journal Environmental Science & Technology. This map is available for free for non-profit use, if cited properly. Required minimum citation includes the source name, map name, year published, and links back to project page (or displays url). Example: "Source: UC Berkeley CoolClimate Network Average Annual Household Carbon Footprint (2013)"