Courtesy of Dave and Matt Simmons I learned that the Center for Global Energy Studies (CGES) has just released a report on Oil's Depletion Rate (pdf file). Since this is the basic concern that underlies a considerable portion of the current debate about Peak Oil, and figures being quoted for depletion vary from 2% to 14%, depending on which field, and which period one is discussing, I looked for some enlightenment in their conclusions.

I learned, to begin with that

Although it seems straightforward, depletion as a concept is not easy to pin down. The very use of the word "depletion" in this context - synonymous as it is with exhaustion - implies that oil resources are being run down and that one day they will dwindle into insignificance. Oil resources may well become insignificant in the years to come, but it is not certain whether this will be due to their physical exhaustion or to the world moving away from oil and towards another source of energy.

Unfortunately, this suggests, as does the tone of much of the article that follows, that being concerned about oil supplies, largely from the point of the reserve available, is a pointless worry. I say unfortunately because this cornucopian view of the world of oil glosses over the changing situation in the world and conceals some of the assumptions that it makes, by hiding them within the overbounding simplification of its argument.