Venice may seem an unlikely place to think about globalization. At the right time of year, at the right time of day (before the half-naked tourists descend on San Marco like a barbarian horde) the Queen of the Adriatic can seem as if she has been exempted from the 21st century. Not to mention the 19th and the 20th.

Usually I come here to forget about modernity; to immerse myself in an urban past that seems almost uniquely intact. It is, I know, an illusion. The mere absence of cars does not make this the same city that Canaletto grew up in 300 years ago. The internal combustion engine disturbs the peace here too, albeit in a lower, water-borne register. The appetites of budget travellers have altered the city’s economy, just as the emissions of nearby heavy industry — incongruously visible on the skyline — have altered the lagoon’s ecology.

On the plus side, of course, you are unlikely nowadays to expire prematurely in a cholera epidemic, the fate of Thomas Mann’s Gustav von Aschenbach in “Death in Venice.”

Yet precisely because history did leave Venice behind, architecturally if not in other ways, this is the ideal place to ponder the vast economic changes we are witnessing in our time. For what befell Venice roughly 500 years ago may well be the imminent fate of the city’s North American counterpart: New York.

Just as the world economy tilted away from Venice in around the year 1500, condemning it to relative decline, slow stagnation, and ultimate relegation from metropolis to museum, so it could now be tilting away from what was once the greatest entrepôt of the Atlantic world.

It’s not just the American investment bankers fretting that London is doing more deals than New York. Much more financial restructuring is needed in Europe’s still fragmented economy than in the United States, so London’s lead is hardly surprising, regardless of regulatory differences. Far more impressive is the coming shift identified by Princeton’s Alan Blinder in a recent working paper titled “How Many U.S. Jobs Might Be Offshorable?”

Looking closely at which activities are most vulnerable as Asian competition ascends the value chain from manufacturing into services, Mr. Blinder estimates that “somewhere between 22 per cent and 29 per cent of all U.S. jobs are or will be potentially offshorable within a decade or two.” That could be one in four jobs.

Right now, much more attention gets paid in the American press to illegal immigrants, most of whom come from Mexico. But they compete only with the least skilled Americans: fruit-pickers and hotel maids. The new generation of high-skilled but still low-paid Asian graduates can stay at home and still compete, not only with computer programmers and telemarketers, but also with accountants and financial analysts. Even with corporate lawyers and derivatives traders. In short, with New Yorkers.

For more than a century, Manhattan has been the financial hub of the Atlantic economy, the place where North American financial services attained critical mass. If Mr. Blinder is right, that could change — and soon. The more business opportunities arise to the east of New York, the less advantageous its location becomes. And the more New Yorkers’ skills are replicated elsewhere, the less need there is to employ New Yorkers.

Now think what happened to Venice. In 1500, the city was at the very zenith of its economic power. It was the hub of the European economy, the place where Christendom, the Levant, and the Orient met. The wealth it derived from trade and finance was what made possible the monuments we admire today, just as it made possible the armies and navies with which the Venetians vanquished their rivals.

Then came Columbus. The discoveries and conquests in the New World after 1492 began a profound reorientation of the world from East to West. As silver and sugar flowed one way across the Atlantic, migrants and slaves the other, new business opportunities arose that favored Amsterdam and London. In effect, the merchants of Venice found their jobs “offshored.”

Yet it was not so much the New World that did for Venice as the discovery of a new route, round the Cape of Good Hope, from the Old World of Europe to the even Older World of Asia. Once Portuguese, Dutch, and later British ships could transport spices and silks from the Orient to the Occident without need of the old overland routes, La Serenissima had lost the three things a successful trading center depends on most: location, location, and location. The decline from great power to pleasure garden and so on down to pawn (of French and Austrian emperors) was slow but inexorable.

Is a similar reorientation of the global economy happening today? Yes. The 400 years after Columbus saw a spectacular divergence of economic fortunes, with the West growing wealthy and the East stagnating. New York exemplified the Western triumph. Over the past century, however, that process has been reversing itself, fitfully and painfully to begin with, but inexorably. Ever since Meiji Japan proved that Asians could match Europeans both economically and militarily, we have been living through the “great re-convergence.” And in the past 20 years Asia’s catch-up has dramatically accelerated.

The result has been a perceptible shift in the global balance of power, comparable in its historical significance to the great surge forward achieved by Western Europe and its colonies of settlement in the late 18th and 19th centuries.

There are, of course, worse ways to decline and fall than the path down which Venice slid. Though occupied by foreign armies on more than one occasion, La Serenissima was never bombed flat. It may be depressing to see traders replaced by tourists, but it beats becoming rubble. So perhaps New Yorkers should just shrug their shoulders. If the economic action is fated to migrate eastwards, at least their city has already established itself as an alluring tourist destination — much as 18th-century Venice did. Whenever I fly over Manhattan I am powerfully reminded of the view of Venice from the air: each densely built-up, each surrounded by water. Sub specie aeternitatis, the two cities do have much in common. They are both beautiful.

The question is whether history will oblige us by repeating itself so neatly. For not every historical conjuncture does become a fully-fledged secular trend. Consider the following scenario, which could prematurely cut off the great East-West re-convergence:

1. Democrats in Congress slap protectionist tariffs on Chinese goods.

2. A defiant President Bush launches air strikes against Iran, sending oil soaring up to $100 a barrel.

3. The Chinese stock market, which is now unquestionably in bubble territory, tanks.

4. The Chinese economy judders to a halt, causing unemployment and unrest across the country.

5. In dismay, the more cautious elements in the Communist Party clamp down, but this time they lose control.

Such a scenario certainly belongs on the list of “low probability, high impact” events, but definitely not on the list of “wholly impossible, no impact” events. After all, one of the principal reasons for China’s dismal economic performance throughout the 19th and most of the 20th century was precisely its internal instability. Think only of the Taiping Rebellion (1851-1864), a peasant revolt estimated by Western contemporaries to have claimed between 20 and 40 million lives — more than the World War I.

There is still the possibility, then, that New York retains an historic edge over its new Asian rivals, in good old-fashioned political stability. Never mind Shanghai; even London is a significantly more dangerous place than New York these days. Since 9/11, much more has been done to disrupt terrorist networks in America than in Western Europe. If I had to name just one “high probability, high impact” event that fills me with dread, it would be an act of nuclear terrorism directed at the British capital.

Venice, as I said, has been lucky in the gentleness of its decline. London may be less so. The next bad thing that happens — whether in Europe, the Middle East or Asia — will painfully remind us that the ultimate safe haven is still the one with the Statue of Liberty at its entrance.

Mr. Ferguson is the Laurence A. Tisch Professor of History at Harvard University.