can anyone 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?
There's no real saturation point. The effect is approximately proportional to the logarithm of the concentration, so each extra ppm will do less.
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.
Iout, W / m2 = 287.844
Iout, W / m2 = 284.672
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.
In the "Gore warming"(my name) years, which show very convincing evidence that man is the primary cause of global warming,...
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?