A bell shaped curve depicting global and US oil production developed by M. King Hubbert in the 1950's. The computation predicted that US oil production would peak around 1970 and global oil production would peak around the turn of the millennium. Although the US prediction was surprisingly accurate the global prediction was slightly off. Instead of a peak a plateau is currently being observed. Many people use this observation to "debunk" peak oil.
Hubbert's peak is central to the peak oil community and discussions. With the recent advancements in petroleum engineering and exploration more advance models have been developed to predict the future of oil production. Even thought the global oil production hasn't really begun to decline many people are fairly certain that we have already peaked.
Pessimist: Hubbert's peak is a valid expression of simple mathematics, physics, and economics.
Optimist: What the fuck are you talking about its the government's fault gas is so high.