"This Is the Fifth Time the World Has Run Out of Oil,": Daniel Yergin

...Whenever markets are tight and prices are high, you get this fear that the end is near. There's a picture in "The Quest" of Woodrow Wilson walking to church and he said I'll have to walk to church because we'll have gasoline-less Sundays in the United States, because we didn't have enough oil. In the 1970s, it was thought that we were going to run out of oil and, of course, it turned out that there is a lot of oil. The theory today is that we're about halfway through the global endowment. Our view is that we're probably more like 20 percent, based on what we know today. _StLToday

It is possible that Daniel Yergin is correct, and we have used 20% of the global endowment of oil. But not likely. The real figure is almost undoubtedly less than 10%, probably much less.

Around 2007 was probably the high point of oil demand in the United States, and it's going to go down because our cars are going to get a lot more efficient, there's more biofuels, and the other is the demographic change. We have an aging population that drives less. So all of those things add up.

You can see Detroit has kind of changed its mind just in terms of how they're selling cars, and the emphasis on efficiency. Everybody has in the back of their mind that gasoline prices could go up again and that affects people's decisions. I think all of that means our oil demand is kind of on a glide path downward, though there may be a bump when we come out of the downturn.

... The output of the oil sands is now equivalent to the Libyan exports before the civil war. It's a big number. It could double by the next decade. It's next door to us. It doesn't have to come here by tankers. It's part of a larger trading relationship. And I think it really contributes to energy security.

I think the real controversy isn't about the [Keystone XL] pipeline itself, because we have lots of oil pipelines in the United States. The real opposition is to the oil sands themselves. And it's an argument about carbon. It is a tough issue for the administration because environmentalists are part of their base. But it may be the biggest shovel-ready project in the country if you take direct and indirect jobs. It's hard in an environment with 9 percent unemployment to say no to it. _StLToday

Yergin is a believer in climate alarmist orthodoxy, and yet he favours the construction of the oilsands pipeline, Keystone XL, and the further development of the oilsands. This reveals Yergin's underlying pragmatism -- something that too many orthodox carbon hysterics lack.
Back to the question of how much of the world's hydrocarbon complement has been used:

It is the opinion of Al Fin energy analysts that the chart above understates the overall global hydrocarbon complement -- particularly in terms of crude oil and natural gas. But that should become clear over the next few decades, as the technologies required to find and produce these underestimated hydrocarbons become available.