The Middle East, and the Gulf in particular, is holding the economic destiny of the world in its hands.
I am tempted to write "again", but that would belittle the uniqueness of the situation in which the global economy finds itself. Revolution in North Africa, a sudden leap in oil prices, and the fragility of the recovery from the financial crisis of 2008 combine to produce a one-off set of economic circumstances.
It is too early to call it an economic crisis (although of course there is a full-blown sociopolitical crisis in North Africa), but we are only a little way off a "perfect storm" of economic factors that could blow global recovery off course and sweep us back into recession.
Over the past four decades, there has been an almost complete match between Middle East political problems, oil price rises and global economic difficulties. The October 1973 war, the 1979 Islamic revolution in Iran and the Gulf War of 1991 all caused dramatic rises in the price of crude and periods of difficulty in the global economy.
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These were sometimes severe enough to be labelled "recessions", as in 1973-1975 and 1991-1993. And after the Iranian revolution, the world economy languished in the doldrums for a number of years.
A debate is still raging among economists as to the causes and effects of the crisis of 2008. Did the western-inspired credit crunch tip the world into financial crisis and cause the severe spike in the oil price of that summer? Or did the spike and subsequent relative collapse of the price of crude prick the bubble of asset values and send us into the recession of 2009?
It's a chicken-and-egg situation that will probably never be satisfactorily explained, but the general principle still holds: rising oil prices are not good for the world economy.
In terms of the scale of price rises, this time we are in completely new territory. In 1973 and 1991, oil prices rose by a bit less than 200 per cent; after the Iranian revolution, they roughly doubled - spiking about 100 per cent. But between 2002 and the peak in August 2008, the rise was a staggering 500 per cent.
Old analyses do not necessarily hold in these conditions. Six years ago, the International Energy Agency calculated that an increase of $10 per barrel would reduce GDP in the industrialised world by 0.4 per cent per year and add 0.5 per cent to inflation. But that was when oil was a bargain at $25 per barrel.
After the price of Brent crude briefly nudged $120 this week, the mathematics need reworking. But who knows where prices will stabilise?
Goldman Sachs, the great bull of the oil price in 2007that was nearly proved right when oil hit $149, is once again suggesting $200. Nomura, even more aggressive, says that in certain circumstances oil could hit $220. At that absolute level, a few bucks probably won't make much difference.
Most economists agree: anything north of $150 per barrel for a sustained period would have a disastrous effect on the global economy. According to one analysis by Thomson Reuters, anything over $95 a barrel for a year or more would stop global GDP growth, forecast at 4.9 per cent this year, in its tracks; at Nomura's $220, the world economy would shrink by a shocking 1.4 per cent.
Western consumers, who in Europe and the US have been charged with leading their economies out of recession, would have to pay so much more for their trips to the shops they wouldn't have any spare cash once they got there. Inflation fears are already there in the West, and dramatic oil price rises would simply confirm and compound them.
In Asia, the giant industrial engine credited with doing most to pull the world out of recession since 2008, higher oil would add significantly to manufacturing costs and consumer inflation. The Chinese economic model would start to creak, and the geo-financial tensions between the US and China - the great legacy of the 2008 crash - would be magnified and exacerbated.
From a Gulf perspective, you might say: so what? Most oil exporting countries in the Middle East budget very conservatively, and any energy revenue above, say, $70 per barrel is pure cash in the bank. The temptation might be to take advantage of high prices while they last.
But this is no longer a realistic policy, as Saudi Arabia has recognised with its promise to make up the shortfall caused by Libyan disruption. The blow to global trade would be equally disastrous for the region, especially for economies such as Bahrain and Dubai that do not have huge energy reserves.
The Gulf reaction, led by Saudi Arabia, has so far been entirely appropriate and responsible. But the problem is that so many variables lie outside the control of Riyadh, Abu Dhabi and Doha.
Any number of geopolitical developments could endanger stability and send oil sky-high: unforeseen disruption to Saudi production; increased tension between Iran and the US; renewed military confrontation between Israel and the Palestinian Territories.
For the world economy, these truly are uncharted waters.