When the oil price rocketed in 1973, everyone knew what the reason was. Opec, tired of supplying cheap oil to the world, flexed its muscles by cutting supplies and massively increasing prices, resulting in a global economic slowdown.
This time there is less agreement and more finger-pointing for the more than doubling of oil prices in the past year to a record $139.12 a barrel. Demand has no doubt increased, partly on demand from rapidly growing countries in emerging markets, led by China.
Until now, Opec has rejected claims from the United States and other oil consumers that there is not enough oil to go around and instead blamed the surging cost on speculators.
Tony Hayward, the chief executive of BP, dismisses the idea. But it is clear that investors have increasingly turned to commodities to add to their portfolios, causing concerns about a bubble. According to Mr Hayward the main constraints are political and not ecological. Supplies are controlled by regimes in countries such as Russia and Kazakhstan as well as the states of the Middle East. Some of these countries are exercising their new-found power by holding back reserves.
What is certain is that further large increases in the oil price can wreak huge damage on the global economy. The Group of Eight major economies said at the weekend that rising commodity prices were replacing the credit crunch as the main threat to world growth.
If prices rise above $200 a barrel, as some analysts are predicting, the "new stagflation" – slowing growth combined with higher prices – will take an even firmer grip on the world economy as inflation continues to rocket and businesses and households rein in spending and investing. Central bankers are preparing to raise interest rates to cope with the increase in prices even amid claims that we may be heading for the worst economic slump since the Great Depression.
Whether speculators bear some of the blame or not, the demand for oil has been driven by all of us as the long global economic boom and rising living standards have boosted demand for the goods that China and other manufacturing nations churn out. It may be that what is needed to bring oil prices down is the very recession that policymakers grappling with the problem are trying to avoid. The Saudis may now have realised this and decided to act to ward off that prospect.
However, there may be a beneficial by-product. Faced with massive costs, governments and businesses will invest more in finding alternative sources of energy.
Beyond the current debate about who is to blame for the exploding cost of oil, the grim truth is that in the long run the stuff is going to run out.