Gold, Oil, and Global Warming
According to the late Thomas Gold, oil and natural gas deposits did not come from fossils but instead came from the materials the Earth was made of (discussed on Classical Values). This is actually the case with Saturn's moon, Titan, so it is not completely absurd … although it is highly speculative.
This theory has important implications for the possible global warming crisis. If all the fossil fuel comes from fossils, there can't be that much of it: We are likely to run out before the CO2 accumulation can be a major problem. If the “fossil fuels” are as abundant as Gold said, it's much more likely for for the greenhouse effect to be a problem.
ObSF: “Wildcat” by Poul Anderson.