I highly recommend reading this entire letter. If you don’t have time, here is the key point:
This is the core idea of every official climate model: For each bit of warming due to carbon dioxide, they claim it ends up causing three bits of warming due to the extra moist air. The climate models amplify the carbon dioxide warming by a factor of three — so two-thirds of their projected warming is due to extra moist air (and other factors); only one-third is due to extra carbon dioxide.
That’s the core of the issue. All the disagreements and misunderstandings spring from this. The alarmist case is based on this guess about moisture in the atmosphere, and there is simply no evidence for the amplification that is at the core of their alarmism.
Weather balloons had been measuring the atmosphere since the 1960s, many thousands of them every year. The climate models all predict that as the planet warms, a hot spot of moist air will develop over the tropics about 10 kilometres up, as the layer of moist air expands upwards into the cool dry air above. During the warming of the late 1970s, ’80s and ’90s, the weather balloons found no hot spot. None at all. Not even a small one. This evidence proves that the climate models are fundamentally flawed, that they greatly overestimate the temperature increases due to carbon dioxide.
This evidence first became clear around the mid-1990s.
At this point, official “climate science” stopped being a science. In science, empirical evidence always trumps theory, no matter how much you are in love with the theory. If theory and evidence disagree, real scientists scrap the theory. But official climate science ignored the crucial weather balloon evidence, and other subsequent evidence that backs it up, and instead clung to their carbon dioxide theory — that just happens to keep them in well-paying jobs with lavish research grants, and gives great political power to their government masters.
Throughout mainstream climate ‘science,’ models always seem to trump measurements. This is wrong as pointed out here. Longtime readers of this blog will note the last paragraph jives with my contention there is no institutional incentive to disprove ‘global warming.’ And, that is wrong and anti-science.
UPDATE Monday: Roger Pielke, Sr. chimes in on the same subject.