Okay, climate science is a tough nut to crack for everybody, but this has been wracking around in my brain lately as far as the argument for CAGW. The rise in CO2 levels obviously has a variety of positive and negative feedback effects, such as increased levels of water vapor in the atmosphere (positive) and increases in some types of cloud-based albedo (negative). Supporters of the CAGW theory, by saying that the effect of positive feedbacks in the climate system as a result of a CO2 increases greatly outdoes the effect of negative feedbacks, imply that there is a critical mass of CO2 concentration in our atmosphere, beyond which the existing climate systems cannot reverse temperature and resulting CO2 increases. The fundamental problem with this is then that CO2 levels have both increased significantly and have been significantly higher over the course of the Earth’s history. Therefore, one needs to ask why the Earth is not already a giant fireball? One would have to get downright creative, it seems, to say that there is not going to be a significant net negative feedback emerge, if it has not emerged already, that will affect climate on a roughly equal scale as the positive feedback. Does anyone (warmists and skeptics alike) have any insight on this matter?
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