SO NOW WE KNOW. If the demand for oil grows at a surprising rate, and the supply is constrained, the price will rise. Add myriad threats of supply disruption, an infrastructure which has been starved for capital and environmental permits for a decade, and a producer cartel, and you get increases that are sharp and enduring. Anyone who missed that lesson in his elementary economics course will certainly have learned it from the business press in recent months.

Unfortunately, concentration on daily price movements diverts attention from the more threatening changes taking place in oil markets.