Zone, that was a great link about oil! I grew up in Alberta, and have lived here now for 13 years as an adult. All my life I have been surrounded by oil derricks, christmas trees (and oil term) and watched the pumps go up and down pulling the oil out of the ground. And now the dreaded tar sands, which has boosted our economy beyond belief. The county I live in is building upgraders to process the tar sands, and that will cause more pollution than the actual pulling it out of the ground.
I was always suspicious of the biotic origins of oil. From grade 5 on, we always had these diagrams of trees and other vegetation being slowly pressured into oil. In my child's mathematical mind, I always tried to fathom how many miles of vegetation you would need to produce the vast amounts of oil we have in Alberta - and that is miles straight up, not sideways.
The overabundance of a calcium carbonate underlay here, combined with the iron, and the need to use CLR on everything, because these two minerals are in our water supply, makes complete sense to me. In fact, the soils here become more alkaline from the calcium, during dry spells, when iron and Calcium Carbonate are drawn up through water evaporating to the surface.
As for global warming, I feel we have fluctuations in weather all the time. There was a mini ice age in Britain back in 1000 AD. It was so cold the English channel froze. When Krakatoa exploded in the 18th century the mean temperature of the earth went down 2C (that's about 4F) and any lower and it would have precipitated another ice age. It took several years to get all the volcanic ash out of the air. Sunsets on the other side of the world, were the most brilliant colours of red, caused by filtering of the sunlight through the volcanic dust.
So my thought is that there are many cataclysmic reasons why the temperature of the earth goes up and down. I remember when Mt. St. Helens blew up in Washington State, to the south of where I lived. That was a winter so cold, that the water pipes burst in several interior BC towns.
So my thought that a bit of global warming may be good, in the event of any kind of increasing volcanic activity. And it just could be that the earth is a bit closer to the sun, and therefore we are warming up more. There are so many factors, to blame people for global warming is really a shot in the dark. Yes, it is happening to a small degree. But why, is the important question!