In 1956, M. King Hubbert, chief consultant for the Shell Development Company's exploration and production research division, forecasted that U.S. oil production would peak in the early 1970s. He subsequently updated this prediction using newer data, but the predicted timing of peaking did not change significantly (see Hubbert  for a review and references to earlier papers). In 1971, U.S. annual production of crude oil peaked at slightly more than three billion barrels (bbl).
Yet, Hubbert's model continues to be challenged by some. For instance, according to economist Michael Lynch, president of Strategic Energy and Economic Research, Inc., Winchester, Mass., it was only after Hubbert published his predictions “that the Hubbert curve came to be seen as explanatory in and of itself, that is, geology requires that production should follow such a curve” [Lynch,2003].