Just as the credit crunch seemed to be passing, at least in the US, another and much more ominous financial crisis has broken out. The escalation of oil prices, which this week reached a previously unthinkable $130 a barrel (with predictions of $150 and $200 soon to come), threatens to do far more damage to the world economy than the credit crunch.

Instead of just causing a brief recession, the oil and commodity boom threatens a prolonged period of global “stagflation”, the lethal combination of high inflation and economic stagnation last seen in the world economy in the 1970s and early 1980s. This would be a disaster far more momentous than the repossession of a few million homes or collapse of a couple of banks.

Commodity inflation is far more lethal than a credit crunch for two reasons. It prevents central banks in advanced economies from cutting interest rates to keep their economies growing. Even worse, it encourages the governments of developing countries to turn their backs on global markets, resorting instead to price controls, trade restrictions and currency manipulations to protect their citizens from the rising costs of energy and food. For both these reasons, the boom in oil and commodity prices, if it lasts much longer, could reverse the globalisation process that has delivered 20 years of almost uninterrupted growth to America and Europe and rescued billions of people from extreme poverty in China, India, Brazil and many other countries.

That is the bad news. The good news is that the world is not as impotent as is often suggested in the face of this danger, since soaring commodity prices are not the ineluctable outcome of some fateful conjuncture of global economic forces, but rather the product of a typical financial boom-bust cycle, which could be deflated - especially with some help from sensible political action - as quickly as it built up.

The present commodity and oil boom shows all the classic symptoms of a financial bubble, such as Japan in the 1980s, technology stocks in the 1990s and, most recently, housing and mortgages in the US. But surely, you will say, this commodity boom is different? Surely it is driven by profound and lasting changes in global supply and demand: China's insatiable appetite for food and energy, geopolitical conflicts in the Middle East, the peaking of global oil reserves, droughts caused by global warming and so on. All these fundamental points are perfectly valid, but they tell us nothing about whether the oil price will soon jump to $200, stay at $130 or fall back to $60 next month.

To see that these “fundamentals” are all irrelevant, we have merely to ask which of them has changed in the past nine months. The answer is none. The oil markets didn't suddenly discover China's oil demand nine months ago so this cannot explain the doubling of prices since last August. In fact, China's “insatiable” demand growth has decelerated. In 2004 it was consuming an extra 0.9 million barrels a day; in 2007 it was consuming just an extra 0.3 mbd. In the same period global demand growth has slowed from 3.6 mbd to 0.7 mbd. As a result, the increase in global demand growth is now well below last year's increase of 0.8 mbd in non-Opec production, according to Mike Rothman, of ISI, a leading New York consulting group.

Why, then, are commodity prices still rising? The first point to note is that many no longer are. Rice, wheat and pork are 20 to 30 per cent cheaper than they were two months ago, when financial pundits identified Asian and African food riots as the first symptoms of a commodity “super-cycle” that would drive prices much higher. And the price of industrial commodities such as lead, zinc and nickel, supposedly in short supply a year ago, has now dropped by 40 to 60 per cent. In fact, most major commodity indices would already be in a downtrend were it not for the dominance of oil.

But oil is the commodity that really matters and surely the latest jump in prices proves that demand really does exceed supply? Not at all. In the late stages of financial bubbles, it is quite normal for prices to become completely detached from economic fundamentals. House prices in Florida and Spain kept rising even after property developers built far more homes than they could possibly sell. The same thing happened in credit markets: mortgage securities kept rising even while banks created “special purpose vehicles” to acquire vast “inventories” of bonds for which there were no genuine buyers - and dozens of similar examples can be cited from the bubbles in internet stocks and Japan. Similarly, the International Gold Council reported this week that gold demand for commercial uses and investment fell 17 per cent in January, just as the gold price surged through $1,000 for the first time.

Now consider the situation today in oil markets: the Gulf, according to Mr Rothman, is crammed with supertankers chartered by oil-producing governments to hold the inventories of oil they are pumping but cannot sell. That physical oil is in excess supply at today's prices does not mean that producers are somehow cheating by storing their oil in tankers or keeping it in the ground. All it suggests is that there are few buyers for physical oil cargoes at today's prices, but there are plenty of buyers for pieces of paper linked to the price of oil next month and next year. This situation is exactly analogous to the bubble in credit markets a year ago, where nobody wanted to buy sub-prime mortgage bonds, but there was plenty of demand for “financial derivatives” that allowed investors to bet on the future value of these bonds.

In short, the standard economic assumption that supply and demand drive prices is only a starting point for understanding financial markets. In boom-bust cycles, the textbook theory is not just slightly inaccurate but totally wrong. This is the main argument made by George Soros in his fascinating book on the credit crunch, The New Paradigm for Financial Markets, launched at an LSE lecture last night. In this book Mr Soros explains how financial bubbles always start with some genuine economic transformation - the invention of the internet, the deregulation of credit or the rise of China as a commodity consumer.

He could have added the Netherlands' emergence as a financial centre triggering Tulipmania or Britain's global dominance as a naval power before the South Sea Bubble of 1720. The trouble is that these initial perceptions of a new paradigm tell us nothing about how far financial prices will adjust in response - will Chinese demand drive oil prices to $50 or $100 or $1,000?

Instead they can create a self-fulfilling momentum of rising prices and an inbuilt bias in the way that investors interpret the world. The resulting misconceptions drive market prices to a “far from equilibrium position” that bears almost no relation to the balance of underlying supply and demand.

The people who tell you that commodity prices today are driven by “economic fundamentals” are the same ones who said that house prices in Britain were rising because of land shortages. The amazing thing is that just months after losing hundreds of billions in the housing and mortgage bubbles, investors and governments around the world have reverted to the discredited fallacy that financial markets always reflect economic reality, instead of the boom-bust cycles and misconceptions that George Soros's book vividly describes.

More oil news from Times Online Business

Times Recommends

• Hysteria alert: Fab One tour starts
• Whodunnits? A cultural religion
• Prison works. So why won't we admit it?