Global warming is mostly anthropogenic

I do not question that there has been an increase in human-produced CO2 or a general warming trend in climate since the end of the Little Ice Age, in the early 1800s. CO2 is indeed a greenhouse gas, and polls of climate crisis skeptics produce nearly unanimous agreement that anthropogenic CO2 causes some global warming. That's never been an issue. What is unproved and unlikely is the claim that 75% or more of global warming is due to anthropogenic CO2. If CO2 dominates climate, then global warming should have increased through the last decade, because CO2 has continued to increase. But global warming has at best stalled for a decade, and climate now is switching to a cooling trend.Climate SensitivityIf CO2 only acted according to the straight physics of greenhouse gases, the temperature increase would be small. Richard Lindzen, MIT professor of meteorology, explains:"After all we are still talking about tenths of a degree for over 75% of the climate forcing associated with a doubling of CO2. The potential (and only the potential) for alarm enters with the issue of climate sensitivity—which refers to the change that a doubling of CO2 will produce in GATA. It is generally accepted that a doubling of CO2 will only produce a change of about two degrees Fahrenheit if all else is held constant." [1]Doubling CO2 produces a 2 degree increase, Pro notes the actual CO2 increase has been about 30%. Climate crisis advocates claim that the effect is multiplied, and that is the issue. The multiplier is climate sensiivity."... current [CO2] climate models predict much higher sensitivities. They do so because in these models, the main greenhouse substances (water vapor and clouds) act to amplify anything that CO2 does. This is referred to as positive feedback. But as the IPCC notes, clouds continue to be a source of major uncertainty in current models. Since clouds and water vapor are intimately related, the IPCC claim that they are more confident about water vapor is quite implausible." [1]The article further explains how the paleoclimatological evidence makes high sensitivity unlikely.Atmospheric Temperature ProfilesCO2 global warming advocates do not claim that CO2 is causing the increased radiative reflectivity and the cooling troposphere, They claim that CO2 is increasing water vapor in the atmosphere which in turn produces the temperature profile. Thus the temperature profile is consistent with any theory that increases water vapor. There are many other possible causes, including changes in atmospheric convection patterns, changes in cloud cover, and ocean temperature changes.Another possibility is that methane is the greenhouse gas culprit. Methane was once thought to be mainly a product of human activity, but data in 2007 showed that some natural effect caused a dramatic worldwide change in atmospheric methane. Natural methane changes may act to cancel other causes of temperature change. [2]A decade of cooling defies CO2 modelsPredictions of warming from 2000 to 2010 made by CO2 models were way off. Temperatures have been way below the error bands claimed for the models. [6,7]A much better fit to observation is that the cyclical trends of the past several hundred years are continuing, with a small upward trend from increases in CO2. [7]"The Pacific Ocean has a warm temperature mode and a cool temperature mode, and in the past century, has switched back forth between these two modes every 25-30 years (known as the Pacific Decadal Oscillation or PDO). In 1977 the Pacific abruptly shifted from its cool mode (where it had been since about 1945) into its warm mode, and this initiated global warming from 1977 to 1998. The correlation between the PDO and global climate is well established." [4]Much of the polar ice cap melted in the 1930s and before that in the 1880s, just as it did around 2007. In each case, colder climate followed, as is happening now. The question of what causes the PDO is unanswered.Climate is complexThe theory of CO2 dominated climate hinges upon climate being simple, CO2 advocates say that in the past other factors like solar variations, earth orbit changes, and volcanoes contributed to climate, but that now none of that is happening so climate change must be entirely due to CO2. That idea is now so thoroughly discredited that a fresh look at climate science is required. "What causes the deep meridian overturning of the ocean, redistributing heat around the planet? We don't know. ... [other basic unanswered questions] ... Kerry and Dan assert that the predictive power of climate models has plateaued and is not likely to improve until questions like these are answered." [3] SurveyPro's link only goes to the abstract of the survey; the paper hasn't been published. The abstract links to a page of how the survey authors compiled their list of 1372 climate scientists to survey. The authors divided climate scientists who, in the authors words are "convinced by the evidence (CE) for anthropogenic climate change or unconvinced by the evidence (UE) for ACC.." 903 are "convinced" of anthropogenic climate change and 472 are "unconvinced." Thus according to the authors, 34% of climate scientists are not convinced of anthropogenic global warming. So where does the 97% figure cited by the authors come from?We don't know because the authors don't say exactly what questions they asked, who responded, or how many of the responses they kept. Although we don't know in this case, here is how climate crisis advocates have managed the feat in the past. Referring to a previous survey of over 10,000 earth scientists: " ... close examination of the source of the claimed 97% consensus reveals that it comes from a non-peer reviewed article describing an online poll in which a total of only 79 climate scientists chose to participate. Of the 79 self-selected climate scientists, 75 agreed with the notion of AGW. " [5]Of the 10,000 scientists surveyed in that effort, only 79 responded. The survey linked by Pro was conducted by Pratt and his associated, who are very vocal advocates of climate crisis. So who responded to the Pratt survey of 1372 scientists? It's likely that most skeptics did not bother responding.The figure of 34% skeptics is on the low end of estimates made by Patrick Michaels [8], who puts it between 35% and 50%. A surveyed of degreed meteorologists in the American Meteorological society produced "Only 24 percent of the survey respondents agree with United Nations Intergovernmental Panel on Climate Change (IPCC) assertion, “Most of the warming since 1950 is very likely human-induced.”Taking a prominent stand against climate crisis can cost a scientist his job, so skeptics tend to keep a lower profile than crisis advocates. For comparison, back in the 1960s the Steady State Theory was favored by about two-thirds of scientists over the Big Bang. The Big Bang is now stongly favored. Science is not determined by a vote.Pro has the burden of proof to show 75% of global warming is anthropogenic. The science does not provide that proof.1. http://online.wsj.com...Lindzen is widely acknowledged as the foremost expert on climate circulation models.2, http://www.tgdaily.com...3. http://www.realclearmarkets.com...4. http://www.globalresearch.ca...5. http://hockeyschtick.blogspot.com...6. http://wattsupwiththat.com...7. http://rankexploits.com...8. Shattered Consensus: The True State of Global Warming, Rowman & Littlefield, 20059. http://www.heartland.org...