Almost 50 years ago, the geologist M. King Hubbert developed a method for projecting future oil production. He calculated that oil production in the lower-48 states would peak about 1970. His prediction has proved to be remarkably accurate. Both total and peak yields have risen slightly compared to Hubbert's original estimate, but the timing of the peak and the generally declining production trend are correct. For the last 50 years, many geologists and oil companies have published estimates of the total amount of crude oil that will ultimately be recovered from the Earth over all time.
Net energy is the pre-condition for all other resources.
The coming peak in global oil production signals the end of the consumer economy because nothing can replace conventional oil. Economists frequently cite Canada's Athabasca oil sands as a handy replacement for conventional oil. But oil sands and tar shale are very energy-intensive, environmentally destructive, and not all that large anyway. Oil sands would last just three years if we super-optimistically assume 25 percent net energy for the digging, etc. over the entire resource. Unlike oil, natural gas can not easily be shipped by sea.