Facing an annual decline rate of 4 or even 4.5 per cent, the world must discover and bring online the equivalent of a new Saudi Arabia â€” or one could equally say, a new United States, complete with the shale boom â€” every four years, or perhaps every three, in order merely to maintain current rates of production.
The rate of decline reflects the depletion of major oil regions like the North Sea and the North Slope of Alaska, and the decreasing flow from countries that were once among the world’s largest producers such as Indonesia and Mexico. But it also reflects the difficulty in increasing production in countries that were supposed to account for much of the future growth in the supply of conventional oil, in particular the three large producers of the Persian Gulf, Saudi Arabia, Iran and Iraq.
Mitchell, Timothy. Carbon Democracy: Political Power in the Age of Oil. Verso; London. 2013. p. 261-2