You might enjoy this -
http://image.guardian.co.uk/sys-files/Guardian/documents/2001/08/14/resources-biodiversity.pdf
"In 1914 the US Bureau of Mines estimated that there would be oil left over for only ten years’ consumption. In 1939 the US Department of the Interior projected that oil would last only 13 more years, and again in 1951 it was again projected that oil would run out 13 years later. As Professor Frank Notestein of Princeton said in his later years: “We’ve been running out of oil ever since I’ve been a boy.”
Worked with a few old oil engineers once. They were always told to say "we are going to run out of oil in 30 years". Because if they said "500" the price would bottom out and if they said "4" the price would spike to high.