Green Metropolis is the title of a well written book by David Owen which challenges conventional thinking. He argues that residents of compact urban centres, such as New York, individually consume less oil, electricity, and water than other Americans. They live in smaller spaces, discard less trash, and, most important of all, spend far less time in cars.  Residents of Manhattan- the most densely populated place in North America -rank first in public-transit use and last in per capita greenhouse-gas production, and they consume gasoline at a rate that the country as a whole hasn't matched since the mid-1920s. They are also among the only people in the United States for whom walking is still an important means of daily transportation.

The world’s population is increasing, as is the move of people from rural to urban environments.  So planning for high density urban centres, rather than suburban sprawls, seems the best route to sustainability.