Main Question or Discussion Point
can any one tell me what the saturation point of CO2 is in the atmosphere in relationship to it's effect as a green house gas? At what point does extra CO2 have no more effect?
let me rephrase that then. What is the effective saturation poit? I realize that there is a diminishing return, but at what point?There's no real saturation point. The effect is approximately proportional to the logarithm of the concentration, so each extra ppm will do less.
please this is exactly what I was looking for.Let's rephrase the correct answer then,
on this graph we used the calculation model MODTRAN to compute the theoretical radiative balance with increasing concentrations of CO2 and CH4 assuming no feedbacks. For each order of magnitude increase of concentration 1- 10 -100 etc, the radiative balance is restored at about a fixed increase in temperature according to the model. The dimishining return starts at the beginning.
But then again, it's only a model
Happy to explain how it works, if it interests somebody.
while the graphs show a nice absorbtion spectrum with dips for CO2 around 700 (?units?), O3 around 1000 and CH4 as of 1200Iout, W / m2 = 287.844
Assuming no change in the solar input, we now have radiation unbalance, less energy, about 3.2 W/m2 getting out. Hence the surplus energy, not reradiated back to space is heating the Earth until the balance is back to the original energy value (287.844 W/m2). Therefore we increase (trial and error) Earths temperature (Ground T offset, C) with 0.89 degrees and, lo and behold, we are back to the original radiation balance value. Hence doubling CO2 in a tropical atmosphere would seem to lead to an increase of 0.89 degrees C. That is if radiation balance is necesary and you wait long enough for that to happen.Iout, W / m2 = 284.672
Perhaps 'saturation point' is the wrong term for what I am talking about. The article I read(which I unfortunately can't find any more) stated that our atmosphere was only capable of 'trapping' or 'holding on to' a certain level of CO2. Something akin to say... carbonating soda water. The water will only 'hold' so much carbonation and eventually the extra gas will just be lost. So according to this article the excess CO2 apparently would leave the atmosphere. I'm unsure now of this idea that it would just drift off into space, whether or not it is possible (though I imagine it would be).That should be correct. Of course we are looking at a complex carbon cycle.
You could compare the carbon (carbon dioxide + methane etc) in the atmosphere with a bucket of water, filled by several water taps but drained by holes in the bottom. Within certain limits, if the draining equals the filling, both being constant, then the water level is constant as well, increase the rate of filling and the water level will increase, which increases the draining rate due to the increased water pressure. As soon as the draining rate matches the filling rate again, the water level stabilizes again but at a higher level. Dynamic stability. If that's what you would call, saturation point, then sure, with constant rates of filling and draining the CO2 level should reach a dynamic stability point/saturation point.
Edit: I'm tired. I reread and I think you did understand.
Edit: I just reread your response and it seems that maybe I misunderstood and only thought you misunderstood me. or something like that. I'm tired.
The carbon filling and draining of the atmosphere is supposed to look like http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/earth_system/carbon_cycle_NASA.jpg [Broken].
It's more complex than the bucket, looks more like many buckets, where the rate of exchange between fast and slow cycles is important. The upper ocean - atmosphere exchange is fast buthttp://www.geographypages.co.uk/weathering.htm [Broken] as well as organic carbon burial are much slower cycles. It would require for that part to match the fossil fuel burning rate before dynamic stability can be reached. The fossil fuels would probably deplete first, which also would limit the maximum CO2 concentration.
Have you seen the (mandatory in the UK) guidelines?In the "Gore warming"(my name) years, which show very convincing evidence that man is the primary cause of global warming,....
Doesn't seem so, as the rate of increase of CO2 concentration is not levelling off at all.has the very significant increase in CO2 in that period been accompanied by a similar and corresponding measurable increase in the biomass of photosynthetic organisms that perform the main CO2 reduction function on earth?