Even with large supplies of coal and natural gas, the world faces a potential energy shortfall, one reason that the U.S. Department of Energy suggested in a 2005 report (pdf) that a "crash program" to cope with any decline in oil supplies be instituted. The report argued this program should start 20 years before peak global production to avoid "extreme economic hardship." That's because it will take decades for any kind of energy transition to occur, as evidenced by past shifts such as from wood to coal or coal to oil.
In fact, King and Murray argue that global economic growth itself may be impossible without a concurrent growth in energy supply (that is, more abundant fossil fuels, to date). "We need to decouple economic growth from fossil-fuel dependence," King adds. "This is not happening due to industrial, infrastructural, political and human behavioral inertia. We are stuck in our ways."
Has the 'Era of Easy Oil' Ended?