The term "Sustainable City" is an oxymoron. And will remain so for as long as metrocentrics continue to regard their city as separate to the environment. They try to balance economic, social and environmental outcomes by separating them rather than mixing them together.

They gather exclusive economic and social outcomes to themselves while the ecological outcomes, and their costs, are apportioned almost exclusively to areas outside the cities. And they then criticise the overburdened farmers for excessive whinging.

The metrocentric bears the environmental costs associated with their economic and social benefits and simplistically reason that rural folk should not complain about their lot because they enjoy compensating environmental benefits. That may be but health and education still cost as much, if not more, in the bush.

A truly sustainable Sydney CBD would have vegetated buffers by the Tank Stream. Building heights would be set by the height of the adjacent Blackbutts and there would still be a beach at circular quay. Instead, there is concrete everywhere.

And to compensate for this failure, and to maintain a self delusion of environmental sensitivity, the workers in Phillip Street apply regulations that preclude even the most temporary of disturbances within 20 to 100 metres of any farmer's creek bank.

The urban public must understand that the essence of sustainability is balance between economic, social and environmental values and that, by definition, must incorporate limits on scale and intensity.

It is the disproportion in the scale and intensity of urban living that contributes most to environmental degradation. Any excess of atmospheric CO2 is not caused by the exhaust emissions of a farmer, or farmers collectively, because their emissions are at a scale that actually fertilise their trees and pastures. There is no compensating absorbtion of urban emissions. Enter Global Warming.

Urban existence need not follow the London, LA to Mexico City model. The Swiss, with autonomous States (Cantons) and small, high density but socially nourishing cities that remain in touch with their hinterland, are so much closer to a sustainable balance.

But are our cities already too far gone to help themselves?

Readers of this article might be interested in research by prof Ed Glaeser at Harvard that identifies the real causes of obesity (in Americans) and it's largely to do with widespread availability of cheap high calory foods, and not reduced exercise or much to do with urban form / structure or transport choices; see: http://post.economics.harvard.edu/hier/2003papers/HIER1994.pdf
This article was referenced in Andrew Leigh's article in On Line Opinion of 27th May 2003.