When Will the Oil Run Out?

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Science  01 Jul 2005:
Vol. 309, Issue 5731, pp. 52-54
DOI: 10.1126/science.309.5731.52

In his Policy Forum “Oil: Never cry wolf—why the petroleum age is far from over” (21 May 2004, p. 1114), L. Maugeri has done considerable double-counting to reassure us that “the world is not running out of oil.” He cites various upward revisions in historical estimates of oil reserves and resources, culminating in the 2000 U.S. Geological Survey estimate of 3021 billion barrels of ultimately recoverable resources, from which he draws the conclusion that “overall, the world retains more than 3 trillion barrels of recoverable oil resources.”

Unfortunately, that 3021 figure includes the oil that has already been consumed. It consists of “undiscovered conventional oil” (732 billion barrels), “reserve growth” (688 billion barrels), “reserves remaining” (891 billion barrels), and “cumulative production” (710 billion barrels) (1). Deduct the 710 billion barrels already consumed, and the remaining oil totals 2311 billion barrels, a figure closer to other estimates.

Maugeri ignores the fact that the discovery of reserves lowers the estimate for undiscovered oil; it does not necessarily raise the total figure for ultimate recoverable oil resources.

He also calculates a “life index” of 40 years for known reserves, using current consumption figures. Using the 891 billion barrels (reserves remaining) figure would reduce that number to 32 years, but there are flaws in that calculation. Making projections based on current consumption is meaningless if consumption is rising (which it is). With a projected annual growth worldwide of 1.9% from 2001 to 2025 (2), the 32 years' supply would decline to about 26 years.

I believe we should draw very different conclusions from the present estimates. First, although the experts may quibble over their differences, they are in broad agreement: All the estimates I have seen agree within a factor of about two as to how much oil remains. The policy implications are not much different, wherever you may stand in that range. Oil resources are running down, and the supply is inelastic.

Second, we should be preparing now for a difficult transition. Europe and Japan, poor in oil resources, have gone much farther in making adjustments in energy use than the United States. Furthermore, they have stable or declining populations and similar requirements for energy and have chosen to limit demand, particularly by imposing high taxes on gasoline.

The United States is putting itself in the worst possible position for the energy transition by encouraging unchecked population growth (mostly driven by immigration) and doing very little to encourage energy efficiency.


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