I'd like it if people could present more ideas about how cities might deal with the problems facing us, such as resource depletion and global warming. That would be great.
I no longer live in the city (born again country boy) but I did live in “Ecotopia,” i.e., Portland, Oregon, for 15 or so years. Here are some things off the top of my head that the Portland area has done that might pertain to your question Ludi---mostly relates to green infrastructure and transportation:
--Subsidized street tree planting and natural area restoration to reduce sewer overflows, improve neighborhoods, reduce energy use, provide habitat, etc. (this was my full-time job for a while)
--Expanded community gardens (not nearly enough, last I heard there were 1,000 people on waitlists)
--Built a fair number of bioswales
--Encouraged green roofs (tax credits, subsidies, public education, etc.) for stormwater runoff and various other environmental goals
--Expanded park system, much of it natural areas
--Focused what most cities would consider an inordinate amount of time on developing a bicycle-friendly environment (as a former bike commuter I think they still have a ways to go)
--Built a trolley system downtown and a small but growing light rail grid---bus service is also pretty good, but could be better and has gotten worse since recession---general sense from the local powers is that public transportation is a good thing that should be encouraged
--Encourages density and “close-in” living and a walkable city (at least 'close-in')---new urbanism is the buzzword in city hall
--Organized a peak oil task force, though I have zero idea as to what they do or how influential they are
--Have let the road system deteriorate to Third World conditions to accustom us to the peak oil apocalypse on the horizon
Still, it's a big American metro area with all the sprawl, overconsumption, overpopulation, car-centric, fast food, strip mall characteristics of any American city. Just less bad.
A garden will make your rations go further.