Ethisphere just put out an article about the 20 most sustainable cities in the world by 2020. Of course these lists are kind of silly, but what I liked most about the article was the recent revelation from The United Nations: 2008 is the first year in history where more than 50% of people worldwide live in large Urban areas. Apparently city live is too good to escape from! :-)
It further goes on to say that suburban life is proving to be ineffective in terms of health, quality of life, and overall efficacy as areas for people to live.
“There’s a clear indication now that suburban living is associated with obesity and high rates of lung and heart disease,” says William Rees, professor at the University of British Columbia’s School of Community and Regional Planning and founder of the ‘ecological footprint’ concept. “The nature of planning in North American cities, which tends to separate residential from commercial from shopping uses, virtually forces everyone to use a car.”
As citizens from London to Bombay to any other large, well-developed city will tell you, cars are not only unnecessary in downtown living; they’re a downright headache to use. On top of the gas money savings from stowing your vehicle, a lack of cars creates some health benefits. "People that live in downtown areas where they don’t use vehicles as much, but walk to work, walk to restaurants, walk to shopping and so forth, those people on average weigh less and have healthier cardiovascular systems than people living in the suburbs,” says Rees.
“Eco-densification, densifying urban development, getting out of sprawling situations is a remarkable improvement in public health and it has the additional advantage of further reducing automobile dependency, the higher densities result in much more economically viable public transit systems and clearer advantages.”
The article is rather lengthy and describes exactly what makes a city "sustainable" in the eyes of planners. Only New York and Chicago were mentioned as large American cities that are sustainable, though Portland, Oregon was mentioned as a great mid-sized city in terms of 'greenness' and stability.