Think the creation of multi-million populations takes centuries? Not any more. Cities get created very fast in China.

In both China and the Persian Gulf, cities comparable in size to New York have sprouted up almost overnight. Only 30 years ago, Shenzhen was a small fishing village of a few thousand people, and Dubai had merely a quarter million people. Today Shenzhen has a population of eight million, and Dubai’s glittering towers, rising out of the desert in disorderly rows, have become playgrounds for wealthy expatriates from Riyadh and Moscow. Long-established cities like Beijing and Guangzhou have more than doubled in size in a few decades, their original outlines swallowed by rings of new development. Built at phenomenal speeds, these generic or instant cities, as they have been called, have no recognizable center, no single identity.

Rapid economic expansion creates a condition where lots of people who didn't use to be able to afford much housing suddenly can. Plus, the Chinese government and people look upon economic growth the way a much poorer American people used to see it: as a great thing.

Whereas many Americans want to protect old houses of supposed historical value in China massive new buildings are all the rage.

“In America, I could never do work like I do here,” Steven Holl, a New York architect with several large projects in China, recently told me, referring to his latest complex in Beijing. “We’ve become too backward-looking. In China, they want to make everything look new. This is their moment in time. They want to make the 21st century their century. For some reason, our society wants to make everything old. I think we somehow lost our nerve.”

Holl has reason to be exhilarated. His Beijing project, “Linked Hybrid,” is one of the most innovative housing complexes anywhere in the world: eight asymmetrical towers joined by a network of enclosed bridges that create a pedestrian zone in the sky. Yet this exhilaration also comes at a price: only the wealthiest of Beijing’s residents can afford to live here.

I think part of the nostalgia for old buildings in the United States comes from a desire for permanence as a source of security. But if you really want security in a form that most matters then how about supporting bigger efforts to create rejuvenation therapies. Then instead of watching your face and body gradually crumble they will look youthful for decades and therefore far more permanent.

Affluent people in areas with lots of really poor people want protection. I flash on the Todos Santos gated arcology community in Jerry Pournelle's science fiction book Oath Of Fealty. The newly affluent in India live in new gated high rise communities.

GURGAON, India — When the scorch of summer hit this north Indian boomtown, and the municipal water supply worked only a few hours each day, inside a high-rise tower called Hamilton Court, Jaya Chand could turn on her kitchen tap around the clock, and water would gush out.

The same was true when the electricity went out in the city, which it did on average for 12 hours a day, something that once prompted residents elsewhere in Gurgaon to storm the local power office. All the while, the Chands’ flat screen television glowed, the air-conditioners hummed, and the elevators cruised up and down Hamilton Court’s 25 floors.

Hamilton Court — complete with a private school within its gates, groomed lawns and security guards — is just one of the exclusive gated communities that have blossomed across India in recent years. At least for the newly moneyed upper middle class, they offer at high prices what the government cannot, at least not to the liking of their residents.

I expect an acceleration in the reshaping of communities. While we face a shortage of liquid fuels energy in the next 5 to 10 years eventually technological advances will make energy cheap again. Plus, robotics and nanotechnologies will lower the costs of fabrication and construction. My worry is that much of the planet's surface will eventually become constructed and fabricated.