Be interesting to know where the .5 million comes from.
from Little Warming with new Global Carbon Cycle Model
Seems to me if it really takes half a million years for carbon entering the atmosphere to leave it, we'd still be suffering from the various eruptions that have occurred over that period, yet even IPCC graphs show the effect tapering off within a few years.

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I’m not sure what you mean by “adjusted”, but yes the stratosphere is cooling, just as the models predict.


The only real sink for Carbon is the formation of Carbonate rocks like limestone. This process takes millions of years.

It takes a couple hundred years for CO2 to spread itself though the earths ecosystems after it’s emitted by burning fossil fuels and CO2 levels will drop while this happens. The carbon itself is still there cycling between the land air and ocean, so the final equilibrium point for CO2 will be higher and remain that way for a very long time.

As lomiller said, the CO₂ is distributing itself throughout the oceans and such, and therefore the levels will decrease on a timescale of hundreds of years. However, the final equilibrium reached through this process will be higher than before, and the only process to truly reach equilibrium in the long term is carbonate rock formation, which is the reason for the 0.5 million year number.

Also, volcanic CO₂ comes primarily from the melting of carbonate rocks in subduction zones, which is the other part of the natural equilibrium (the CO₂ is deposited as carbonate rocks at the bottom of the ocean, then rereleased into the atmosphere when it comes out of volcanoes and such in the subduction zones). Because of this, it's not surprising that the overall levels have not been tremendously affected by volcanic CO₂, although it can cause temporary fluctuations.

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Good for you, Acolyte. Your post, here, pretty much put things into perspective, not only with respect to the fact that the Earth is hardly "on fire," and has been much hotter many times before (probably sans polar ice cap), but also our "whopping" 0.28% contribution to the Greenhouse effect, and water vapor's overwhelmingly vast majority of contribution to said effect.

Also kudos on the link to the scandanavian sunspot correlation research.

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As pointed out in that thread, the fact that it was warmer before humans existed isn’t exactly relevant to the current discussion, and the 0.28% figure is a deliberate attempt at deception. (Acolyte simply being a victim of that deception not the originator.)

CO2 makes up 0.28% of greenhouse gasses by volume but it’s much stronger then the most common greenhouse gas. CO2 makes up about 30% of the total greenhouse effect, and unlike water vapor it can stay in the atmosphere long enough to cause climate change. Water vapor on the other hand simply turns to rain in a few days.

If it wasn't for water vapor in the atmosphere, we would be freezing at night and roasting during the day. If the amount of water vapor in the atmosphere is increasing, even though it lasts only a few days, the overall average water vapor content of the atmosphere is ialso ncreasing and could be a major factor in global warming.

The only thing that can make a meaningful change in the amount of water vapor in the air is a global change in air temperature.

There can be a net increase in atmospheric CO2 from organic processes. Global carbon includes atmospheric, surface and subterranean carbon. Atmospheric carbon level changes as a function of how much carbon there is at surface and sub-surface. Large scale bio-engineering can shift carbon from the air to the ground, for example by covering 1% of the ocean with algae farms. This alludes to an idea in the OP, in that we can manage global atmosphere by building fresh water lakes at sea, capturing the sunlight that falls on them, and converting it to algae for use as fuel, fertilizer and stock food.

Re the net level of CO2 and vegetation, a well written article by Freeman Dyson in the New York Review of Books at http://www.nybooks.com/articles/21494 comments that

“Well written” isn’t a term I would use for Dyson. His basic premise is that we could genetically engineer CO2 sequestering plants. The problem is that the amount of fossil fuels still in the ground (mostly coal) represents more carbon then is currently sequestered on land.

Furthermore, if you did successfully genetic engineer something like a carbon sequestering algae how would you tell it to stop if it ever got into the wild? It seems to me such an organism would be even more dangerous then the already serious problem it’s intended to “solve”.

Looking at the orders of magnitude, there are roughly 3000 gigatonnes of CO2 in the air (387 ppm)*. This compares to historic levels more like 2000 gigatonnes (~280 ppm). Planetary engineering is needed to remove this excess teraton of carbon from the atmosphere, at a time when human sources are accelerating the addition of carbon from coal. Large algae farms in sheltered bays would use varieties that would not compete in the open environment, and would be separated from the surrounding ocean by fabric tanks. Large volumes of algae could be grown on shallow sheets in the ocean. By floating say a square kilometre sheet of polymer one metre below the ocean surface, bringing nutrient to it from below the thermocline, adding CO2 from a shore based power plant, and storing the resultant algae bloom in fabric waterbags where oil lipid content would increase, it is possible to provide fuel both for electricity plants and diesel vehicles. A major new source of biodiesel can be produced that will be competitive against sources such as palm oil and soy, as well as against fossil fuels when carbon tax is added. With 71% of our planet covered by sea, the need is to use this surface area to regulate the atmosphere.

* http://en.wikipedia.org/wiki/Carbon_...9;s_atmosphere