What has the food crisis got to do with Northern Rock? Quite a lot, actually. The rocketing price of wheat, soya beans, sugar, coffee etc is all part of the credit crisis which has caused panic in financial markets and encouraged investors to take their money out of risky mortgage bonds and shaky equities and put it into commodities as "stores of value". Put another way, the Western banks are exporting their debts to the third world. DATA FILE ARTICLES: * 2008: The year of global food crisis * Mother of all bubbles to burst * Eat Local: Sunday Herald Campaign * Report: World Food Situation * Hunger & Health * Report: Food Outlook

The phenomenal increases in food prices are only in part a consequence of climate change and population. Most of the recent rises have been the result of speculation and the collapse in the value of the dollar. This is being tacitly encouraged by the central banks, such as the US Federal Reserve, who are trying to ignite another asset bubble to replace the real estate and dotcom bubbles which have burst in spectacular fashion. It's the third bubble and it's hitting the third world hard.

Desperate for quick returns, trillions of dollars are being taken out of private equity and financial derivatives and ploughed into food and raw materials. The financial websites call it the "commodities super-cycle". It ranges from precious metals at one end, to corn, cocoa and cattle at the other - speculators are even placing their bets on water prices.

The collapse in the price of the dollar means that most international commodities are more expensive for poor people. The dollar's decline is a result of the low interest rate policy of the Federal Reserve. When rates are set below the rate of inflation, investors have to keep moving their massive funds from sector to sector in search of higher returns.

They piled into the internet stocks in the 1990s as the boom in dotcoms got under way. Then they shifted into real estate and complex financial derivatives such as collateralised debt obligations based on sub-prime US mortgages. Now, with the collapse of the property bubble across the world, investors are on the move again, and the only place left is commodities.

Of course, long-term factors such as the depletion of oil, population and the changing eating habits of Southeast Asia are putting long-term pressure on agricultural resources. But the Fed has thrown fuel on the fire by dramatically cutting interest rates, even as inflation grows, in a desperate race to revive the American economy on the back of a commodities boom. The people who suffer most will be on the other side of the world.

Will it work? In the short term, possibly. But the US may be cutting its own throat. Once speculative prices get out of control, there is no knowing when they will stop. Oil is over $100 a barrel, which is causing gas prices and fertilisers to rocket in the US.

They depend on these as much as sub-Saharan Africa. This might be the bubble to end all bubbles.