The human effect on global warming is significant.

Since many parts of our debate are really about the same topic, I will combine them and will therefore only be responding to a few of my opponent's statements. =========== Source Credibility =========== RealClimate Yes, RealClimate is a blog. However, it is not just any blog. It is written and maintained by ten publishing climatologists [1], and is therefore more credible than the word of a single climatologist. The mere fact that it is a blog does not change its credibility. Friedenreich I could not find a free copy of "Solar Radiation Absorption by Carbon Dioxide, Overlap with Water, and a Parameterization for General Circulation Models", so I cannot read it. But according to Gavin Schmidt of RealClimate, the paper was measuring short-wave radiation [2]. Greenhouse gases have the most effect on long-wave radiation (in the 12 to 18 micrometer range), and short-wave radiation mostly just passes through the greenhouse gases. So the effects of water vapor and CO2 according to that paper are mostly irrelevant, since they deal with shorter wavelengths. [3] From 1978 Age is irrelevant. If a paper is older, it makes it no less credible. We still follow that ancient 400-year-old theory about "gravity" after all. (Yes, I know that Newtonian gravity is not completely accurate, but it works for all practical purposes and we still use it.) ============== CO2 vs. Water Vapor ============== My opponent claims that 3-8% is relatively small. But in terms of climate, this is nothing to scoff at. "a 5 or 6 ï¿½C cooling was associated with the huge ice sheets 20,000 years ago" [3, 1], and that was only a small percentage increase. Although 9-26% is nothing like the 66-85% effect of water vapor, it is still easily enough to have a serious impact on the climate. I have recently come across further explanation for why CO2's potency is greater than at first glance. Water vapor mostly absorbs infrared in the 18-30 micrometer range, while CO2 absorbs it in the 8-18 micrometer range. Without CO2, water vapor can only absorb so much radiation; even if it is more potent than CO2, water vapor lets out most radiation below 18 micrometers. But CO2 absorbs much of the radiation that water vapor lets escape, and so CO2 when combined with water vapor absorbs much more radiation than water vapor alone. Additionally, more infrared is in the 8-18 micrometer range than is in the 18-30 range, so this further inflates the effect of CO2. [3] [4] Feedback Effect The feedback effect is difficult to calculate, since it is so indirect. Though I would very much like to have a good estimate of the potency of the feedback effect, if we are looking for exact numbers we should just stick with the estimates that we already have in place. ========= Miscellaneous ========= "1)The CO2 by man is still the same CO2 by nature, thus the absorption of CO2 by man is the same as nature's CO2." What I meant is that emitted and absorbed CO2 by nature is roughly in balance (it stayed between 180 and 280 ppm for hundreds of thousands of years). Human emissions threw off the balance. "The Register translated the relevant parts." I'd really prefer a primary source, but by the time my opponent is able to post one, the debate will be over. As it is, I can't say much, because the article does not cite any sources or give any explanation as to why it is reliable. "2) It does not have the significant the support of the scientific community. JSER, MIT etc." Even if we accept that the JSER is a scientific organization, that's still only one scientific organization. MIT is not a scientific society, but a university. ========= Conclusion ========= Humans have seriously influenced atmospheric levels of CO2 and have contributed significantly to global warming. Water vapor, while important, does not reduce the significance of human contributions. The human effect on global warming is undeniably significant. ======== References ======== [1] http://www.realclimate.org... [2] http://www.realclimate.org... [3] http://www.youtube... [4] "Infra-Red Absorption by Carbon Dioxide, with Special Reference to Atmospheric Radiation." Callendar, G.S. Quarterly J. Royal Meteorological Society 67: 263-75. [5] http://www.globalwarmingart.com...