The theory of global warming peaked in 2007 after Katrina and the big Arctic melt. Since then folk began noticing that we had been cooling off, not warming up, and the big events predicted by the alarmists were not happening (big hurricanes, killer tornadoes, rising sea levels, dead polar bears, etc.). Their extreme fear-mongering began to undermine their credibility. ClimateGate delivered a body blow to their diminished credibility when it came out that a small cabal had been tampering with the temperature record and subverting the peer review process. The death blow to the theory is about to be released in a peer-reviewed paper by a former NASA scientist.
The study looked for the "hot spot", an essential feature of the Co2 theory of warming: that in the greenhouse layer of 10 km up we should be seeing more warming over time, creating a hot spot in a time-series map of the atmosphere. This chart from RealClimate shows what it should look like, but very accurate measurements from weather balloons over 60 years do not show it.
In the new study, the hot spot could not be found.
The warmists have seen this rebuttal coming for a while, and have been arguing that the hot spot is there, just hard to detect, despite the simple truth that the weather balloon can measure well within the accuracy required to detect it. The weather balloons measure to 0.1C while the hot spot should be at least 0.6C.
Two spurious studies (Sherwood 2008 and Santer 2008) tried to show that it could be there within a margin of error, but the studies are jokes - one relied on wind-gauges as surrogates for temperature, and the other on statistical flim-flam. Such is how low the warmists have sunk, but at least these papers have the thin veneer of science. You can read a very good debate on this topic here. The fruitless effort to find what is not there has led to an egregious effort to try to fudge the visuals to show what is not there. Here is the simplest comparison of what the models require to what the data show:
Now the warmists are trying to shift the debate from a hot spot to a cooler stratosphere above. Here is one attempt, relying on "his wife" to justify the science. Come on. Here is another which doesn't resurrect the hot spot but instead says all its lack does is point to a failure of the models. Huh? The whole theory is based on the models. Every one of them requires the hot spot - it follows directly from the Co2 greenhouse layer argument. Without it, no Co2-based warming.
I was initially reluctant to put in these counter examples from the blogosphere since they are so weak, but they show how low the level of discourse has sunk. Even the veneer of science has been dropped. All that is left is mockery of skeptics. We have left the world of science and entered the world of parody. Readers of The Onion would understand.
The study also rebuts a second major prediction of the Co2 theory of warming: that Co2 warming is amplified by increased water vapor. Co2 alone cannot fit the climate models, and they all have a plug factor put in for climate sensitivity. The most important physical mechanism for the plug factor is an increase in humidity (water vapor) at the greenhouse layer. Water vapor absorbs more infrared than Co2. The study found that humidity actually was decreasing in the greenhouse layer, negating the effect of Co2.
Co2 was always a flimsy reason for warming. It does not correlate very well to the actual temperature record, and by itself is fairly wimpy. A better correlation was discussed in the prior post: inside of a modest warming since the Little Ice Age, climate is largely driven by the 60 year PDO cycle, which is now trending down. The Co2-based warming theory is likely to sink with temperatures as the PDO puts us into a 30-year period of global cooling. This chart from The Hockey Schtick captures the increasing irrelevance of Co2 and the rising pre-eminence of the PDO and solar cycle to explain global climate.