It seems to me that there will be some large cities livable in in the future, I'm just not sure which ones. Resources of all kinds will become more scarce as our population increases including most notably, energy, water and arable soil. A truly walkable older city, as in pre-automobile, with fairly low tech utilities like water, sounds great.
I've never been to NYC but I believe the water is gravity fed for the most part, it sure looks like people can walk just about where they need to, or at least they once could.
Newer cities, large and small aren't as fortunate, they were designed with the car in mind. There isn't a house within miles of the city center or the light industrial section - the zoning board won't allow it. These cities were either conceived after Levittown or simply renewed their urban core to such a point as to be inextricably linked via freeway to suburb.
But don't count Levittown out yet:
In brief, we find that the more suburbanized is employment -- that is, the more sprawl -- the shorter the average commute.--Traffic and Sprawl: Evidence from U.S. Commuting, 1985 To 1997: UCLA
So even if you live in the ever-maligned suburb but can locate near your work, you are almost as well off as the city dweller who walks everywhere, at least from the commute perspective. After all these suburbs near business parks and strip malls are sort of like the the pre-auto cities albeit with much much lower population density.
Really I'd prefer the well rounded 'burb with some light manufacturing to most any large urban center simply due to the huge expense of changing infrastructure even slightly in the city. The 'burb could change relatively quickly and cheaply to meet dire needs much like some have done to gradually meet lesser goals.
If the energy fairy pulls a Mr. Fusion out of her ear to fuel the commuters and the transportation of goods and food in and out all will be well until we run up against one of the other key resources I mentioned.
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Norman Borlaug is still out there trying to encourage triticale to provide (like he hoped his improved wheat genetics would);
'a temporary success in man's war against hunger and deprivation,' a breathing space in which to deal with the 'Population Monster'Of course the last time around we didn't deal with the monster, we just ate more.
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The infamous 1,500 mile salad, overpopulation, and arable soil limits along with a good measure of extreme monoculture and the limits of our ability to control nature are coming together right in plain sight:
Water scarcity clouds California farming's futureThe once-mighty water infrastructure is old and insufficient, with new canals and storage facilities years if not decades away from completion. Meanwhile, the state's population may double by 2050, heralding bigger water battles between cities and farms.
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