Quote:
Originally Posted by dalem
Right. In a closed system, sure, put more free CO2 in the gaseous envelope and a body below should heat up at a greater rate than "mere" incident radiant energy would indicate. But planetary climate is not a closed system, so CO2 cannot be considered as a de facto driver for this "global warming" thingie.
-dale
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This may be semantics, but it still would be a driver. It will still absorb longwave, and it will still re-emit. I have no idea what you consider to be a
de facto driver. A driver is a driver is a driver, I have no idea what arbitrary line delineates a
de facto driver from a
de jure driver from a
sunday driver.....
The question is not whether that happens or not, but to the extent it does. A "driver" (even if it has signal on the order of 10-9 thingamebobbies) is still a driver. The function does not change; it still acts to re-emit incident longwave; to act as a thermal re-source.
Even the staunchest skeptics typically do not take the stance that CO2 is not a driver; they will say that, due to absorption overlap (or whatever attenuation aspect they believe in), then the full driver "effect" is not met to the level that the proponents state.
If you want to say that the contribution of CO2 is not on the order of the IPCC estimates; nor on the order of the Arhenius estimates; nor for that matter on the order of the Lindzen estimates, that is one thing, and is the subject of a different line of science. It is quite another to say that it doesn't exist in our atmosphere.