The market is a simple-minded beast: supply is tight and disruptions are possible, so the price goes up. But the market is so tight because demand has been growing faster than supply for years, mainly due to the economic boom in Asia, and now the fear is that supplies may have stopped growing altogether. The German-based Energy Watch Group declared last month that global oil output peaked in 2006 at 81 million barrels per day. It will fall to 58 million barrels per day by 2020, it predicts, and to only 39 million by 2030. That would give us just over 20 years to cut our use of oil by half—or, rather, by two-thirds, since world demand for oil is set to increase 37 percent by 2030, according to the annual report of the U.S. Energy Department’s forecasting arm, the Energy Information Administration