Via The Browser, here’s an excellent explanation of what peak oil is, arguing that it is better understood as an economic phenomenon than a geologic one. Peak oil debunkers are often under the mistaken impression that the phenomenon is about the oil running out. That’s not exactly correct. Though there will inevitably be an absolute moment of peak oil (the earth’s resources are not infinite), what we mean when we talk about peak oil today has to do with the supply of inexpensive and easily obtainable oil becoming scarce under pressure from skyrocketing global demand. In essence (from the article):

Thus the geologists are right that the depletion of low-cost oil will produce Peak Oil but it will not be caused by a shortage of oil resources.

The economists are right that there is no shortage of oil resources or oil substitutes but have so far failed to recognise that there is an oil price which cannot be afforded and this constraint will create and define an economic Peak Oil to be differentiated from a geological Peak Oil.

If you believe that peak oil is about one day turning up at the gas pumps to find them dry, you’re mistaken, and that misconception makes it harder to think through the realities of the law of supply and demand when it comes to oil. And that, in turn, makes it more difficult to make the personal and policy choices necessary to build resilience into the system while there is still time.