Buildings go up, economies head down. (Commentary).

New Yorkers spent the last year trying to get used to their new skyline, one without the World Trade Center. The terrorists that knocked down the twin towers did more than change the look of Manhattan -- they also prompted debate about the future of skyscrapers.

Why isn't hard to understand. After what happened with New York's fabled towers, companies may be loath to occupy space that may be a future target. Employees may not want to work in them either. And then there are the massive costs of insuring gleaming new structures against terrorism.

The events of Sept. 11 bring to mind another debate -- that of the "Skyscraper Curse." There's an uncanny correlation between attempts to construct the world's tallest building and financial crises. Be it New York in 1930. Chicago in 1974, Kuala Lumpur in 1997 or the biblical Tower of Babel long before that, efforts to erect mankind's next architectural monstrosity have proved a reliable indicator of economic meltdowns.

Hence the "Skyscraper Index" that Andrew Lawrence, a Hong Kong-based analyst at Deutsche Bank Securities, has been tabulating in recent years. Lawrence's unconventional economic barometer has connected the dots between epidemics of towering hubris and economic problems.

In the late 1920s, the completion of the Chrysler and Empire State buildings coincided with the Great Depression. The 1970s saw the erection of the 1,368-foot World Trade Center and Chicago's 1,450-foot Sears Tower amid stagflation, a fiscal crisis in New York and the breakdown of the Bretton Woods monetary system. The completion of Kuala Lumpur's Petronas Towers in 1997 coincided with the collapse of Asia's economies.

Over-Investment, speculation

The desire to erect the tallest building seems to have much to do with sudden capital inflows that pump up credit creation and confidence. It's often periods of over-investment and financial speculation, fueled by excessive monetary expansion, that drive developers and politicians to architectural one-upmanship.

Precedent: Sears Tower in Chicago.

In recent years, such projects have been brought on less by advances in architectural design and technological innovation than by economic booms.

Developers and politicians alike might be considered both optimists and gamblers. Few ever quit when they're ahead. At the same time, booms in tall buildings -- as well as their changing geographic locations -- mirror not just the timing but the dynamics and fundamental changes in the world economy. Having claim to the world's tallest man-made peak is as much about ambition as it is about excess.

It's ironic, then, that the global economy isn't panning out the way the Skyscraper Index suggests it should. The economies of the nations that possess the five tallest buildings in the world are either booming or doing better than expected.

Could it be that the Skyscraper Curse is no more? Perhaps.

In China, the soon-to-be-completed Shanghai Financial Center will rise 1,584 feet over what's arguably Asia's most dynamic city. A planned project in Hong Kong would be even taller. Beyond that, mainland China and Hong Kong boast six of the 20 tallest buildings currently in use, according to Skyscrapers.com.

China continues to grow at rates approaching 8 percent at a time when much of the global economy is on the verge of recession. And while Hong Kong is experiencing deflation and record unemployment, there's little panic about the city's economic situation.

This isn't the first time the Skyscraper Index hasn't worked out. The opening of New York's Woolworth Building in 1913, for example, didn't presage an economic crisis. It was the world's tallest at the time. But just because Lawrence's economic barometer isn't jibing with recent events doesn't mean we should ignore it.

In the midst of the Panic of 1907, the finishing touches were being put on the 47-story Singer Building. Ditto for the 50-story Metropolitan Life Building. Later on, the completion of 40 Wall Street in 1929 proved to be a harbinger of the Great Depression.

And let's not forget the U.S. boom of the 1990s. In Sept. 1999, the Chicago Plan Commission green-lighted a 1,537-foot giant that would be the world's tallest in the city's Loop district. And, as fate would have it, a bubble in U.S. stocks began deflating a few months later. The upshot is that investors should keep an eye on whether world's-tallest-building-fever continues in the years ahead.

Yet what about the projects early in the works? Are they precursors to economic problems?

China's flurry of construction comes at a time of great uncertainty as it morphs from a socialist economy to a capitalist one. Across the Taiwan Strait, the Taipei Financial Center also aims to be the world's tallest building when it's completed.

Tallest-building projects elsewhere have been scaled back -- which could be good news for those economies if the Skyscraper Curse remains intact.

What all this means for economies and markets is highly debatable. Still, history shows skyscrapers may provide more information than meets the eye. Building trends may just prove to be one of the very few economic barometers with real foundation.

William Pesek is a columnist for Bloomberg News.