I actually don't consider this post off/topic because it bears on energy supplies and climate change. There was a talk here a month ago by a geologist from Imperial Oil, a subsidiary of Exxon Mobil. He said that there are 1.7 trillion barrels of oil in the northern Alberta tar sands and heavy oil at greater depth. So, we should just pull out of Iraq and invade Canada: quickly, while the crazy people are still in power who might do this. Also, we could improve our economy by sending the Iraq war-injured for free "socialized" medicine.
I've heard on conservative talk radio that there is no real oil shortage because there is 1.7 trillion barrels in these Athabaska tar sands. But, Imperial/Exxon estimates that only 10% of that oil should be counted as reserves, because you have to get it out of the ground and it does not flow...and about 10% is economic at the current prices. For context. 170 billion barrels of oil gives Canada the world's 2nd greatest reserves, after Saudia Arabia, and ahead of Iraq and other countries.

I asked the speaker a question about the 1.7 trillion vs 170 billion. I think that we are likely to use all the available oil, and that is a lot of CO2. Just how bad climate change is going to be is going to be highly dependent on how much CO2 (and methane) we put in the atmosphere, and the next couple of decades (including this one) are critical to that. Preindustrial levels were 280 ppmillion, we are now at 380, and if we burn everything available we might reach 600 or more this century (we might get close to that in some of our lifetimes.

The oil companies are mining tar, and moving a spectacular amount of material: settling ponds 8 km (mile?) across for just one project gives some idea of scale.

100 years ago they mined tar on the UCSB campus. The mouth(s) of some of the mines are still evident on campus if you know where to look (depressions...not open(?).
Chris