I also suspect that over the millennia, that the CO2 is held within a safe channel by the oceans’ CO2 sink. When it is far too low, it begins to give up CO2. I do not know this as a fact, but it fits the natural model of these things and it is also likely a rather slow process that reflects the centuries. The reverse process should kick in when the CO2 level abruptly climbs as has happened over the past two centuries. So what do we make of former levels approaching 200 ppm and even earlier levels approaching a supposed optimum of 1000 ppm.
Recall something else, often over looked. The Holocene is only 10,000 years old. It is clearly warmer and climatically stable. That should have caused a great deal of CO2 to be freshly sequestered in new plant growth. Also as the ice retreated, the mosses advanced and created huge frozen peat bogs again trapping huge amounts of carbon. Thus it is no surprise that CO2 was in decline and possibly from a high level.
Pre Ice Age, we believe CO2 was much higher. During the Ice Age it dropped severely provided the numbers here are correct and that the Ice Age was a lot longer than we think. This is not unreasonable.
Then post Ice Age a great deal of available carbon was again converted to plant material.
Yes, we might actually be busy restoring the necessary carbon content.
It all comes back to just how much we wish to trust our proxies.
Humans and Their CO2 Save the Planet!
Posted By Frank J. Tipler On August 5, 2009 @ 6:59 am In . Positioning, Legal, Science, Science & Technology, US News
As the Senate considers the fate of the cap-and-trade bill, we should consider what it means for more carbon dioxide to be added to the atmosphere, something the bill intends to prevent.
Carbon dioxide is first and foremost a plant food. In fact, plants take carbon dioxide from the atmosphere and use the energy from sunlight to combine the CO2 with water to yield glucose, the simplest sugar molecule. Carbon dioxide is also the source of all organic — this word just means “contains carbon” — molecules synthesized by plants. Without carbon dioxide in the atmosphere, there would be no organic molecules synthesized by plants. The less carbon dioxide there is in the atmosphere, the fewer organic molecules synthesized by plants. All animals depend on plants to synthesize essential organic molecules. Without the organic molecules synthesized by plants, the animal world could not exist. Without plants, there would be no biosphere.
Several million years ago, a disaster struck the terrestrial biosphere: there was a drastic reduction in the percentage of CO2 in the atmosphere.
The flowering plants evolved to be most efficient when the percentage of CO2 in the atmosphere was about 1,000 parts per million. But the percentage had dropped to a mere 200 parts per million. Plants tried to adapt by evolving a new, more efficient way of using the little remaining CO2. The new mechanism, the C4 pathway, appeared in grasses, including corn and wheat, which enabled these plants to expand into the plains. If the carbon dioxide percentage had stayed low — or worse, had decreased further — the entire biosphere would have been endangered.
Fortunately for the plants and the rest of the biosphere depending on them, a wonderful thing happened about 150,000 years ago: a new animal species, Homo sapiens, evolved. This creature was endowed with a huge brain, enabling it to invent a way to help the plants with their CO2 problem. Gigantic amounts of carbon had been deposited deep underground in the form of coal, oil, and natural gas. Not only were these reservoirs of carbon locked away in rock, but they were in forms of carbon that the plants could not use.
These wonderful humans, however, worked hard to help the plants. Not only did the humans dig the coal, oil, and natural gas, bringing it to the surface, but they converted these raw materials into the only form of carbon that plants could use: carbon dioxide. Due to the diligent plant-saving efforts of the humans, the CO2 atmospheric percentage is now at nearly 390 parts per million. Were humans to continue in their biosphere-rescuing efforts at the present rate, the CO2 level will be returned to normal in a mere few hundred years.
The cap-and-trade bill is designed to stop this effort to save the biosphere. This is a profoundly evil act. In the words of the Nobel Prize winning economist Paul Krugman, anyone who supports the bill, or any measure aimed at reducing the increase of carbon dioxide in the atmosphere, is “guilty of treason against the planet”!
Those who want to reduce the use of fossil fuels are the mortal enemies of the biosphere. They must be stopped at all costs! Write your senator at once!
The astute reader will have noted that Krugman actually accused those who opposed the cap-and-trade bill of “treason against the planet.” What I have done is use well-known science to show that, from the biosphere’s point of view, it is the cap-and-trade bill that is “treasonable.” Remarkably, Krugman assumes that the climatic conditions of a mere century or so ago are the “natural” ones that must not be changed. A very anthropomorphic point of view is being used to denounce humanity. An ultraconservative reactionary political position is being called “progressive.”