I've been watching a program called Crude on the History Channel. It's the first truly realistic scientific examination of the planetary greenhouse effect that I have seen. It was quite compelling and made far more sense than most of the propaganda pieces out there today.

Scientists compared data from fairly diverse fields of study. They compared past mass extinctions, formation of oil and coal deposits, past climate data extrapolated from both fossil and geologic records, and past CO2 levels.

The CO2 levels could be extrapolated from fossil records of the leaves of ancient plants. The more CO2 there is in the atmosphere, the fewer pores the leaves need to have. These examinations showed that at the times of past mass extinctions and laying the base matter for the formation of oil and coal the CO2 levels were at least 4-5 times higher than present and at some points some 600 million years ago as much as 10 times present levels. Most of this CO2 came from the massive volcanoes that existed all over the globe at the time.

At each of these periods of high CO2, carbon life on the planet was flourishing until the planet warmed to the point that the ice would have melted at the poles and disrupted the thermal currents that keep the oceans flowing and churning. At this point the oceans would become stagnant and anoxic as oxygen levels decreased and sulphate levels increased.

These anoxic periods are supported by fossil records showing sedimate layers where phototrophic purple sulphur bacteria levels increased a great deal, and coincide with both mass extinctions and mass carbon deposits which later formed coal and oil.

Periods of the so-called super greenhouse periods seem to be a natural part of the planet's cycle and can take millions of years to develop. Where some concern is coming from now among the legitimate scientific community (as opposed to the knee jerk panic propogandists) is that our burning of massive amounts of this previously killed off and buried carbon life is speeding up the natural process.

Most of this makes sense and answers many questions including what happened to the dinosaurs. One thing they brought up which creates some unanswered questions is that they said that the killing off and burying of massive amounts of carbon life "resets the planet's thermostat" and cools the planet again. Ummm, if the CO2 was coming from mass volcanic activity how exactly does this work?

That single question seems to be the big hole in the whole theory. If this super greenhouse effect was caused by volcanoes how does the extinction of life counter this? It simply doesn't make sense.

Overall though, these people did a great job of objectively looking at this subject and do present some very solid evidence from a great many different fields of study that seem to support the general idea that while this global greenhouse effect does seem to be a part of the natural cycle of things, we could very well be speeding things up by burning the carbon left over from past events and pumping it back into the atmosphere.

Perhaps we are indeed taking the place of the ancient volcanoes. While our current CO2 levels are still 4-5  times below what was needed to trigger these past global events, it may serve us well to ensure that we don't speed up a process that should take millions of years and compress it into just a few hundred.

I give these people credit for producing a logical, fact based treatise on the subject without any fear mongering or cries of impending doom. We are nowhere near the brink of global disaster as some would like us to believe, but without some serious examination of our wanton burning of carbon we could well take ourselves there over the course of the next century or two instead of the millions of years it's supposed to naturally take.