One of the most recent setbacks is the more recent failure of climate models to predict the present decade long halt to warming, and particularly their lack of correlation between predicted effects of increased CO2 concentrations and their effect on climate.
Some may point to the recent warm spell we enjoyed in the US over the past week or so as proof of AGW. But I recall more than a few really mild winters (and equally bitter cold winters) since I've trodden this earth. It's called weather and it happens all the time.
But back to the main point.
During a fundraiser in Atlanta earlier this month, President Obama is reported to have said: "It gets you a little nervous about what is happening to global temperatures. When it is 75 degrees in Chicago in the beginning of March, you start thinking. On the other hand, I really have enjoyed nice weather."Many of the warmists point to the increase in global temps and their correlation with increased levels of CO2 as the only proof they need. But they choose to ignore that global temperatures started increasing well before the CO2 levels stared rising. So unless CO2 has some kind of temporal effect, meaning that its effects somehow travel through time to cause warming before the levels rise, then we have to look at the possibility that CO2 levels rose because of rising temperatures. Antarctic ice cores showing 400,000 years of climate data suggest just that scenario.
What is happening to global temperatures in reality? The answer is: almost nothing for more than 10 years. Monthly values of the global temperature anomaly of the lower atmosphere, compiled at the University of Alabama from NASA satellite data, can be found at the website http://www.drroyspencer.com/latest-global-temperatures/. The latest (February 2012) monthly global temperature anomaly for the lower atmosphere was minus 0.12 degrees Celsius, slightly less than the average since the satellite record of temperatures began in 1979.
The lack of any statistically significant warming for over a decade has made it more difficult for the United Nations Intergovernmental Panel on Climate Change (IPCC) and its supporters to demonize the atmospheric gas CO2 which is released when fossil fuels are burned.
Perhaps my biggest gripe about the ongoing AGW doomsaying is that all they predict is calamity, yet they have no way of telling us exactly how they came to that conclusion. It's like they assume that any change is a bad change and that there's no way that conditions on Earth might actually get better rather than worse. Paleoclimatology suggests things will be better with a warmer climate. Better that than trying to usher in a another Ice Age.