Why did I quit in disgust? At the time when I left the field ten years ago, the science was already mostly gone from climate research, and it seemed to have been replaced by true believers engaged in the worst form of confirmation bias. The actual science behind the belief of run-away man-made global warming is pretty awful, and involves far more details than what I can put into a single comment to a newspaper article.

But the short version is as follows: The dirty secret is that carbon dioxide is not very effective at absorbing and re-emitting radiation (heat). In short, it does not absorb over much of the infrared spectrum, and much of the area where it does absorb is already covered by water vapor. To get the run-away alarmist greenhouse effect, it is assumed in the climate models (but not verified at all by observations) that the small amount of additional heat from CO2 will cause more water to evaporate from the oceans without (overly simplifying here) causing additional clouds. Water vapor is a very potent "greenhouse" gas, hence the amplification effect in the climate models.

So what are the problems with the above feedback argument? There are three of them. The first is that if this water vapor feedback exists, then why did we not get a run-away greenhouse effect when the earth was actually considerably warmer than the present, such as during the Medieval Optimum (about 1000 AD, when Greenland was farmed by the Vikings), or, say, during the Holocene Maximum about 6,000 years ago? The second argument is that the assumptions about clouds in the climate models are terrible ... the assumption are the conclusions here, and satellite observations do not support the assumptions. The final point is that the theory is failing in its predictions. As an example, if the climate models were correct, then the mid-atmosphere (about 15,000 feet up) should be warming the most rapidly ... satellite data indicate no warming signature at all.

So we have a theory that makes illogical assumptions, has failed to occur in history, and is failing in its predictions. This is not to say that the earth did not warm up during the 20th Century (though it might be cooling off again now, the earth is always growing warmer or colder throughout history), or that CO2 has no effect. It is just not a big effect, and the natural tendency of humans to believe that we are wrecking an otherwise perfect world (recall our religious creation myths) does not a scientific fact make.

I could go on with so many points here, but this is already too long of a post. By the way, I would *not* want to be Al Gore ... the future will not judge that Nobel Prize very well.