The one chart about oil's future everyone should see

When people read about a long-term forecast of world oil supply--say, out to 2030--they often believe that the forecasters are merely incorporating our knowledge of existing fields and figuring out how much oil can be extracted from them over the forecast period. Nothing could be further from the truth. Much of the forecast supply has not yet been discovered or has no demonstrated technology which can extract or produce it economically. In other words, such forecasts are merely guesses based on the slimmest of evidence.