@greenfyre:1. The earth has clearly been getting warmer for the past ~150 years2. This warming is *not* unprecedented as AGW alarmists would have you believe3. Some of this warming *may* have been caused by human-emitted C02, but there are enough uncertainties surrounding the science that further research is needed4. General Climate Models (GCM’s), the computer models used to predict future climate, are inherently flawed5. Considering 2, 3 & 4 above, it is decidedly unwise to spend multi-trillions of dollars economizing a basic building block of life until such time as the uncertainties and flaws are either appropriately accounted for or AGW theory is disproven (at which point spending any money on it would be idiotic).I think it’s fair to say that Greenfyre, Viking and other AGW alarmists would agree on #1, but differ substantively on the remainder. As a result, I’ll not bother providing any links for 1, and 5 is a conclusion that you’ll either come to or you won’t based on 2, 3 & 4. Also, it’s worth noting that in no way am I suggesting any of the following links *prove* AGW theory is wrong. What these links *do* prove is that the science is far less settled than AGW alarmists would have you believe and therefore the burden of proof has not been met for taking action of the kind recommended by alarmists. It may be met in the future or it may not. Time will tell.Here we go, then.1. N/A2. Warming Not Unprecedented.Overview: this matters because a key tenet of AGW alarmism is that human-generated C02 emissions are warming up the planet faster and warmer than ever before. Scary! If, on the other hand, such warming has occurred in the past and had nothing to do with human-emitted C02, then what we’re experiencing today is not unusual, not that scary and therefore probably doesn’t require massive policy decisions to try to counter it.The general case here is that it was just as warm (if not warmer) during the Medieval Warm Period (MWP), a climate optimum of very warm temperatures which occurred around AD 800-1,300, which was followed by the Little Ice Age (LIA), a particularly cold period ending around the late 1700’s or so. From that point, temperatures began rising pretty much to where they are today.Here’s a decent summary of the MWP from Wikipedia:http://en.wikipedia.org/wiki/Medieval_Warm_PeriodNow, this topic is likely to set off a link war all by itself. Why? Because AGW alarmists have taken to claiming that the MWP in particular did not exist, or that it was a localized event to Europe and maybe Greenland. So, first you have to decide if it existed (and if so to what extent), then how warm it was (and whether it was similarly warm to today).2A. Did the MWP exist, and how far was its extent?MWP in New Zealand:http://www.agu.org/pubs/crossref/2002/2001GL014580 ...MWP in China:http://www.springerlink.com/content/gh98230822m7g0 ...MWP in Peru:http://www.clim-past-discuss.net/5/771/2009/cpd-5- ...MWP in California (1)http://www.x-cd.com/mcss04/papers/P47.pdfMWP in California (2)http://www.jcronline.org/perlserv/?request=get-doc ...MWP in Koreahttp://www.sciencedirect.com/science?_ob=ArticleUR ...And on and on. Certainly enough widespread results from a disparate number of published scientists that the MWP should not be written off as AGW alarmists would have it.2B. How Warm Was the MWP?WMP temperatures comparable to today:http://www.clim-past.net/2/99/2006/cp-2-99-2006.pd ...MWP temperatures comparable to today:http://www.climateaudit.org/pdf/others/crowley.amb ...MWP temperatures in Scandinavia much warmer than today:http://www.springerlink.com/content/8j714536501167 ...National Academy of Sciences on contention that MWP not as warm as today:http://books.nap.edu/openbook.php?record_id=11676& ...And on and on. In conjunction with the other links provided certainly enough evidence that it is reasonable to conclude there may well have been a worldwide MWP and that temperatures during it may very well have been comparable to if not higher than today, well before human-caused C02 emissions ever came on the scene. If this is the case then it is also reasonable to conclude that today’s temperatures are not unprecedented and within the range of natural variability.3. Uncertainties with regards to AGW being human vs. naturally driven.The earth’s climate is fantastically complex. Could natural causes yet unknown or understood be behind some or all of AGW? Alarmists would tell you no, the natural world is well enough understood and the preponderance of science is enough to conclude that most if not all of the warming since 1950 or so has very likely (eg., 90% chance) been forced by human-emitted C02. So are there no questions as to the accuracy of this?Solar trends and global warming (a reasonably digestible powerpoint) :http://yosemite.epa.gov/ee/epa/wkshp.nsf/vwpsw/84E ...More solar trends (same author – sorry, couldn’t find the links to the actual paper, but this is a nice summary of it. References at the end):http://www.fel.duke.edu/~scafetta/pdf/opinion0308. ...-Worth noting that the above paper was supposedly “debunked� earlier this year. A debunking of the debunking, if you will, is press for publication shortly. Should be interesting.How much will the Sun impact the climate in the coming years? (again, sorry, couldn’t find the link to the actual paper, but this link contains the appropriate references):http://climatesci.org/2009/07/22/new-paper-how-wil ...C02 Absorption in the Atmosphere much shorter than the IPCC says?. This is important because the IPCC and GCM’s assume human-emitted C02 stays resident in the atmosphere 50+ years. If it’s a lot shorter than that, then future C02 estimates vis-à-vis warming may very well be incorrect and the C02 in the atmosphere must be coming from elsewhere (i.e., naturally, as a result of rising temperatures, not the other way around). Sorry, can’t get past the subscription wall, but here’s the abstract.http://pubs.acs.org/doi/abs/10.1021/ef800581rWhere’s the warming in the Troposphere, then? Interesting debate going on here. Some claim that the lack of heat signature in the satellite data for the middle troposphere, which the GCM’s would predict as a unique signature of greenhouse warming, does not exist, disproving AGW. Others say this assertion has been “debunked.�. Here’s the “doesn’t exist� side:http://icecap.us/images/uploads/DOUGLASPAPER.pdfClouds. Not much known about clouds, really, except that they have significant impact on climate of course. Positive feedback (i.e., they warm us up more) or negative feedback (i.e., they cool us down)? Nobody knows. One study has recently been published suggesting a positive feedback, and here’s a quick response to it from Science:http://www.sciencemag.org/cgi/content/summary/325/ ...4. The GCM’s have so much uncertainty that they cannot be used to predict future temperatures.(From the ScienceDaily summary of the actual paper released earlier this year)http://www.sciencedaily.com/releases/2009/07/09071 ..."In a nutshell, theoretical models cannot explain what we observe in the geological record," said oceanographer Gerald Dickens, a co-author of the study and professor of Earth science at Rice University. "There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models."Or, for your general (and thorough) debunking of the models (including all the appropriate references at the end):http://www.sciencedaily.com/releases/2009/07/09071 ...Money quote: “The rapid growth of uncertainty means that GCMs cannot discern an ice age from a hothouse from 5 years away, much less 100 years away. So far as GCMs are concerned, Earth may be a winter wonderland by 2100 or a tropical paradise. No one knows.�-moirende