The world could probably do with another oil shock, as far as the effect of such an event on energy consumption goes.
From John Kemp, at Reuters, a counter-intuitive chart showing the amount of energy consumed in the US compared with the size of the economy; the measures are in British thermal units and constant 2008 dollars. (Click for a larger image)
You can see the rise of cars and domestic appliances through the 1950s and 60s, and then the rush towards energy conservation caused by the oil shocks of the early 1970s.
In 1949, the US was consuming 16,500 BTUs for every dollar of GDP; energy usage peaked at 21,300 BTUs in 1969. Since then, progressive efficiencies have brought usage all the way down to 6900 BTUs, causing Kemp to declare:
The point is that energy consumption DOES NOT have to rise linearly with economic output and living standards. The scope for the households and firms to cut consumption if given the right price signals is enormous.
If energy prices rise high enough and long enough, either because of another oil price spike or as a result of carbon taxes or emissions trading permits, energy use will fall sharply, especially in emerging markets.