The following script is from "China's Real Estate Bubble" which aired on March 3, 2013. Lesley Stahl is the correspondent. Shachar Bar-On, producer.
If trouble comes in threes, then what'll be the next global market to melt down after the U.S. and Europe? Some are looking nervously at China.
China has been nothing short of a financial miracle. In just 30 years, this state-controlled economy became the world's second largest, deftly managed by government policies and decrees.
One sector the authorities concentrated on was real estate and construction. But that may have created the largest housing bubble in human history. If you go to China, it's easy to see why there's all the talk of a bubble. We discovered that the most populated nation on earth is building houses, districts and cities with no one in them.
Lesley Stahl: So this is Zhengzhou. And we are on the major highway, or the major road. And it's rush hour.
Gillem Tulloch: Yeah -
Lesley Stahl: And it's almost empty.
Gillem Tulloch is a Hong Kong based financial analyst who was one of the first to draw attention to the housing bubble in China. He's showing us around the new eastern district of Zhengzhou, in one of the most populated provinces in China - not that you'd know it. We found what they call a "ghost city" of new towers with no residents, desolate condos and vacant subdivisions uninhabited for miles, and miles, and miles, and miles of empty apartments.
Lesley Stahl: Why are they empty? I've heard that they have actually been sold.
Gillem Tulloch: They've all been sold. They've all been sold.
Lesley Stahl: They've all been sold? They're owned.
Gillem Tulloch: Absolutely.
Owned by people in China's emerging middle class, who now have enough money to invest but few ways to do it. They're not allowed to invest abroad, banks offer paltry returns, and the stock market is a rollercoaster. But 15 years ago, the government changed its policy and allowed people to buy their own homes and the flood gates opened.
Gillem Tulloch: So what they do is they invest in property because property prices have always gone up by more than inflation.
Lesley Stahl: And they believe it will always go up?
Gillem Tulloch: Yeah, just like they believed in the U.S.
Actually, property values have doubled and tripled and more -- so people in the middle class have sunk every last penny into buying five, even 10 apartments, fueling a building bonanza unprecedented in human history. No nation has ever built so much so fast.
Lesley Stahl: How important is real estate to the Chinese economy? Is it central?
Gillem Tulloch: Yes. It's the main driver of growth and has been for the last few years. Some estimates have it as high as 20 or 30 percent of the whole economy.
Lesley Stahl: But they're not just building housing. They're building cities.
Gillem Tulloch: Yes. That's right.
Lesley Stahl: Giant cities being built with people not coming to live here.
Gillem Tulloch: Yes. I think they're building somewhere between 12 and 24 new cities every single year.
Unlike our market driven economy, in China it's the government that has spent some $2 trillion to get these cities built - as a way of keeping the economy growing. The assumption is "if you build it, they'll come." But no one's coming.