New York City, New York

Because of the density of its urban form and the extensiveness of its mass transit system, which allow for lower per capita carbon emissions, New York City consumes relatively less energy and produces less greenhouse emissions than most American metropolitan areas. In addition to such infrastructural advantages, New York City has received a considerable boost toward the goals of sustainability thanks to the Bloomberg administration's ambitious environmental efforts.

Several studies contend that a metropolitan area's overall density is inversely proportional to its carbon emissions: Densely populated cities such as New York and San Francisco tend to have relatively smaller transportation and residential carbon footprints than low-density metro areas, which tend to be larger emitters of carbon dioxide per capita. A recent report by the Brookings Institution, ...