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Friday, January 25, 2008

Don't Panic just yet

This video is a very nicely done exposé of the serious flaws in those catastrophic global warming forecasts that you constantly hear being regurgitated by our main stream media.

Climate catastrophists often argue that global warming theory is "settled science." And they are right in one respect: We have a pretty good understanding of how CO2 can act as a greenhouse gas and cause the earth to warm. What is well agreed upon, but is not well communicated in the media, is that a doubling of CO2, without other effects that we will discuss in a moment, will heat the earth about 1 degree Celsius (plus or minus a few tenths). This is not some skeptic's hallucination -- this is straight out of the IPCC third and fourth assessments. CO2, acting alone, warms the Earth only slowly, and at this rate we would see less than a degree of warming over the next century, more of a nuisance than a catastrophe.

But some scientists do come up with catastrophic warming forecasts. They do so by assuming that our Earth's climate is dominated by positive feedbacks that multiply the initial warming from CO2 by a factor of three, four, five or more. This is a key point -- the catastrophe does not come from the science of greenhouse gases, but from separate hypotheses that the earth's climate is dominated by positive feedback. This is why saying that greenhouse gas theory is "settled" is irrelevant to the argument about catastrophic forecasts. Because these positive feedbacks are NOT settled science. In fact, the IPCC admits it does not even know the sign of the most important effect (water vapor), much less its magnitude. They assume that the net effect is positive, but they are on very shaky ground doing so, particularly since having long-term stable systems like climate dominated by positive feedback is a highly improbable.

And, in fact, with the 100 or so years of measurements we have for temperature and CO2, empirical evidence does not support these high positive feedbacks.
Via Warren Meyer at Coyote Blog.

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