If sprawling desert metropolises like Phoenix, Arizona, are going to survive an increasingly scorching climate, they will require a different kind of sustainable urbanism than typical cities, says Aaron Betsky.

Is Phoenix doomed to fall back into the ashes? In his 2015 book, The Water Knife, the author Paolo Bacigalupi imagines a future Valley of the Sun that has shrunk back to its urban core: "a dust-draped sprawl of low-rises and abandoned singe-families slumping across the flat desert basin. Mesa, Tempe, Chandler, Gilbert, Scottsdale – the remains of a metropolitan sea that had flooded the open basin, filling it with houses and arrow-straight boulevards until they lapped against the saguaro-studded mountains at its rim."

It is a scene of total collapse: "In her own mind she imagined Phoenix as a sinkhole, sucking everything down – buildings, lives, streets, history – all of it tipping and spilling into the gaping maw of disaster –sand, slumped saguaros, subdivisions, all of it going down."

What remains of the city is the kind of war zone we know from science-fiction movies and the alt-right's imagination of urban areas today. Downtown, the rich living in high-rises, cocooned with filtered air, abundant water, and cool temperatures.

Ironically, these structures are "arcologies", "a half-alive monster looming over all things Phoenix", filled with "braided waterfalls and hanging gardens", and patterned on architect Paolo Soleri's eco-utopias of the 1970s. They recycle all their waste, including that of humans, and grow their own food. They are also owned by Chinese corporations.

Phoenix shouldn't even be where it is

That is the fate many think will befall not only Phoenix, but most of the other Sunbelt cities of the United States, as well as the growing cities at the edges of the Chinese and Arabian deserts. Once Las Vegas, Tucson, El Paso and Phoenix start to experience weeks of Fahrenheit temperatures not just in the triple digits, but in the 120s and 130s, no air conditioning will be able to make them habitable.

Moreover, their sources of water, from the Colorado River to the groundwater reservoirs and aquifers hiding deep under parts of the Sonoran desert, will dry up. If social strife does not kill these beleaguered cities, the reality of climate change will.

From such a perspective, Phoenix shouldn't even be where it is, at least not at its current size: well over four million inhabitants and growing. It is a human-made ecosystem with no grounding in the dry desert landscape using up prodigious amounts of energy just to be able to survive. But, is the place really such a waste, in every sense of the word?

According to Grady Gammage Junior, an urban-planning lawyer and analyst, the metropolitan area actually holds up quite well by most measures of sustainability. It is denser, believe it or not, than cities such as Seattle, Washington DC, Houston, Detroit, and Atlanta, and has a lower per person carbon footprint than sixteen of the largest Standard Metropolitan Areas, including New York and Chicago (although it does use more water, and at cheaper rates, than all of them).

If social strife does not kill these beleaguered cities, the reality of climate change will

Moreover, it has taken quite a few steps in recent years to increase everything from density to energy conservation, while building a burgeoning light-rail system and including parks along its major transportation routes.

If it is up to the State's Senior Republic Senator, John McCain, it will even reclaim a considerable part of the Rio Salado, as well as the still-extant canals that once irrigated vast reaches of the Valley – all of which once helped make Phoenix the West's "Tree City".

There is a lot the city can still do to improve its future. One fundamental thing the Valley – or we – can do, however, is to stop thinking about it as a traditional city. As Gammage shows in his book, it is not that Phoenix is less dense than other cities, but that it is less gradated in density: with only a vestigial downtown, the city has little of a centre.

Even its cultural core, which in most cities counts as the marker of centre, is here a long line (Central Avenue) that is not quite walkable, even if it is served by a light rail line. Phoenix might be what we think of as the name of the whole area, but Scottsdale is larger in terms of land area, and a city such as Mesa easily ranks as a mid-size city in its own right.

There is a lot Phoenix can still do to improve its future

The Valley is instead a carpet of nodes, some large enough to be Edge Cities per American author Joel Garreau's definition, but many smaller than that: retro downtowns such as Scottsdale's New Urbanist shopping, residential, and resort areas such as the Kierland Resort, Kierland Commons and Scottsdale Quarter, and endless confluences of hospitals and shopping malls, sporting venues and hotels, and resorts, shopping, and residential agglomerations.

What we need to do to make the Valley more sustainable is to concentrate on these nodes, or "stims", as the critic Lars Lerup would have it, and figure out three things: how to make them more sustainable and varied in themselves; how to connect them in a manner that wastes less time and energy; and how to make that landscape of networks and nodes more appropriate to the Sonoran Desert.

We know how to do the first, as sustainable building practices have now reached a point where we can make not just "net-zero", but energy-positive buildings that produce more energy than they consume. Fulfilling the goal of creating true stims also means, however, that we make the housing and the social services in these nodes affordable to all, and that has larger policy and economic implications.

The second goal will demand that we not only embrace such new technologies as driverless cars, but that we also embrace and socialise shared transportation to develop models of light rail, jitneys, shared vehicles, and high-speed direct connections that are available to all.

We need to accept that the dispersed beauty of the Valley is based on openness and scale

Answering to the third goal means that we must learn how to build with, rather than on the land, use riparian patterns as our guides, and in general figure out how to create urban and urbane forms that are common sense and sensible. The extensive complexes of the Spanish missions might offer one model, as might the settlement patterns developed centuries ago in desert landscapes from Africa to Asia.

Notice that what will not work is for Phoenix or the Valley of the Sun to withdraw into its core, allowing the rich to huddle in their control centers and the next-in-lines to congregate around their coffee shops in the rental laagers of the Type 3 behemoths that are now being built all around downtown.

Such a segregation will make Bacigalupi's vision come true. We need to accept that the dispersed beauty of the Valley, and its logic, is based on the openness and scale that still attract tens of thousands of people to move here every year.

The romance of the open range is also the logic of the Hohokam, who built canals fanning out from the Valley's rivers to the foothills of Camelback and other mountains. It is also the dream of dissolving the inefficient and socially stratified snarl of overly concentrated cities to try to recapture the democratic landscape of which Thomas Jefferson dreamed in far-away Virginia.

Phoenix has risen not only from the desert, but also from the ashes of 19th-century urbanism. The challenge now is to make its flight more sustainable, open to all, and beautiful.