In the early 1970s a fourfold rise in the price of oil almost brought the world to a standstill. The shock of the Arab embargo left a deep mark in many countries.
Thirty-five years on, oil prices have quadrupled again, briefly soaring to a peak of just over $135 a barrel. But, so far, this has been a slow-motion oil shock. If the Arab oil-weapon felt like a hammer-blow, this time stagnant oil output and growing emerging-market demand have squeezed the oil market like a vice. For almost five years a growing world shrugged it off. Only now is it recoiling in pain.