Hunting for the answer to the question, "What is the rate of formation of oil deposits compared to present consumption rates", I stumble on to Petroleum Online, and the first thing I find is this:
"The petroleum exploration process, like the process of buying common stock, involves a series of decisions made under uncertainty—we do not know whether oil or gas is present until after an exploratory well has been drilled".
Which exactly parallels what is happening at Copenhagen: there is still a small amount of uncertainty about the details of climate change, but we will have to make the decision under uncertainty.
Thank you, petroleum persons.
Anyway, back to the quest.
How long did it take to make the carbon that we are burning?
Here's a ball park figure.
The Carboniferous period lasted 60 million years.
Let's assume we have chewed our way through 1/6th of the total geologic resource.
That means that we have burned 1n 150 years carbon that took 10 million years to take out of the atmosphere.
Which means that in any one year we are burning carbon that took 64,000 years to be formed.
I think I need to go back to bed...