Most greens have a very flimsy understanding of science or technology, so most when faced with proof that what they have been campaigning for for decades is counter productive is usually met with denial or pseudo scientific responses stated as fact.

Town planners are taught as a fact that high density = low cost of services and low environmental impact. What they are not taught is that better infrastructure is needed, there is no incentive to improve communal property, and people are happier with more space.

Telling them not to try and put people in small boxes is to tear down the temple where they worship.

If we go back 100-150 years, when people lived without all that
energy, they did pretty well on their quarter/half acre blocks,
in a village kind of situation.

They ran a few chooks, grew some veggies and fruit, worked and
socialised locally.

In today's cities, if you switch the power off for half a day,
you have disaster! All those rows of apartment blocks surrounding
cities like Paris and others, are more like a "human zoo".

Crime is so bad in some of those environments, that they have
even knocked some down, for that very reason.

If some urbanites think that living in those human zoos is the
way to go, don't include me in your plans.

I believe the reason you find more greenies in inner suburbs is because of a guilt complex. These people can see the results of their greed and elitism, so try to off set it by jumping on the band wagon, typical hypocrisy by those who see themselves as superior. The majority come from academia and bureaucracy, another hypocrisy, it's their work and decisions which continue these insane polices of increasing urban density and population growth.

Any changes in climate will be felt the most in urban areas as they create their own climate changes and weather patterns, they are unsustainable except with massive energy inputs. Archaeologists and anthropologists in the past have wondered why some ancient cities were deserted without viewable cause. Later research has found they became unsustainable because of dwindling local resources and capacity to sustain them. The same is likely to happen to many cities and closet urbanisation worldwide in the near future.

This discussion is ignoring one very salient fact.
We have arrived at peak oil and depletion has started.
When transport over long distances of food becomes uneconomic the
backyard garden will be literally a life saver.
No one can be certain just when we will arrive at that point, but we
will need years to prepare. We may not have years.

A city plan I visualise is public transport arranged like the spokes
of a wheel together with concentric circular public transport routes.
This would be ideal but must be modified by geography.

In between and adjacent to the residential areas would be local market
gardens able to supply their neighbouring residential areas.
The Permaculture people have done a lot of work not exactly on what
I have described but they have a very good plan for the suburbs.

Do you think you could feed a family on window boxes on a balcony ?