"The Stone Age came to an end not for a lack of stones and the oil age will end, but not for a lack of oil." – Ahmed Zaki Yamani, 2000
"If history is any guide, oil will eventually be overtaken by less-costly alternatives well before conventional oil reserves run out. Indeed, oil displaced coal despite still vast untapped reserves of coal, and coal displaced wood without denuding our forest lands." – Alan Greenspan, 2005