On a gas by gas basis we have a pretty good idea of what level of warming one can expect. Similarly given a particular albedo we can predict what kind of warming to expect. But, on the real earth you have a complex interplay of many gasses and other factors including feedback. And let me be clear that I am not saying any model is perfect...sorry if I gave that impression. What I was saying is that the physics predicts increased CO2 WILL lead to increased warming and we are putting more CO2 into the atmosphere and we are seeing a warming trend that matches the curve of increased CO2 very nicely. There is no other source of CO2 or methane or anything that has changed over the same time period with the same dynamics. But CO2 and warming match very well and we know the CO2 we are putting into the air. Occam's razor (NOT a scientific principle, mind you, but a convenient tool) suggests we explore the CO2 warming idea first.

So far all alternatives (the various water vapor hyptheses, for example...or Rush Limbaugh's idiotic Mt. Pinatubo "hypothesis") to explain modern global warming have fallen flat and been pretty much ruled out, so far anyway. By contrast the predictions of the current anthropogenic models for global warming have made predictions that are coming true. The initial increased snowfall and thickening of the ice sheets even as ice shelves break up. The subsequent loss of ice sheet thickness. Deniers tried using claims that there was increased snowfall and thickness over the ice sheets as evidence against global warming, ignoring the fact that it was PREDICTED by the current global warming models and came true. I haven't noticed much comment on the newer data that the ice sheets are finally starting to thin (as predicted) from the denial lobby. Similarly, I have been hearing for some 15 or 20 years predictions from the current models that we would see, in addition to an overal increase in the average global temperature, we would see an increase in both extremes, more extreme heat as well as extreme cold, and increased storminess. Those were early predictions. And, though increased storminess still remains somewhat controversial, overall those predictions of increased extremes within an overall increase in average temps has come to pass. Yet the deniers used every record cold spell as "evidence" that global warming wasn't happening, ignoring that record cold AS WELL AS record heat was predicted by the models.

I have some updates on this and probably should give it its own diary, but I am finding that Evans'credentials are that he has a PhD in electrical engineering. This gives him no real claim to being a "rocket scientist" (his term) and not necessarily any expertise in climate. So you have an electrical engineer who did carbon accounting for Australia claiming he knows better about climate that climatologists. This alone should raise a red flag in your mind. As to his claims about the "signature"of anthropogenic global warming being "a hot spot about 10km up in the atmosphere over the tropics," turns out this has been debunked already.

The "hot spot about 10km up in the atmosphere over the tropics" is NOT a prediction for doubling CO2. In fact a stratospheric COOLING is a signature for doubling CO2. And we have had stratospheric cooling HAPPEN. In fact that stratospheric cooling for awhile masked another prediction of the current models. The current models predict that surface warming would be accompanied by tropospheric warming. Satellite data (as I mention above) originially did not detect such a tropospheric warming. This was used by deniers as evidence against global warming, and was, in my mind, reasonable evidence. However, a couple of years ago this issue was resolved. The satellite data combined measurements from the stratosphere and troposphere in a way that was not at first appreciated, if I understand correctly. The new info came when these were separated. What was found was tropospheric warming AND stratospheric cooling, which are predictions of the current global warming models based on anthropogenic CO2 release. This is the kind of thing I mean when I say the predictions are precisely correct. Something as complex as surface warming, stratospheric cooling and tropospheric warming, have come true. By conrast the models based on increased solar output do NOT predict stratospheric cooling, so are less acurate.

This article really refutes Evans very effectively and I can't do it justice in this comment. I will however say that you are right that the models have had some major errors. Their basic predictions have come to pass. But the rapidity and severity of the changes have been worse than the models predicted. The pace of change at the poles has been faster than predicted, though the pattern has been correct. Part of the difference is realizing that the dynamics of an ice sheet melting weren't as simple as once thought and that early melting actually sinks large fissures into the sheet, accelerating the melting. THat wasn't predicted, but the error went against the deniers claims even more. There also are predictions that are much more controversial than the basic anthropohenic model. For example the collapse of the North Atlantic current is something I consider unlikely. But keep in mind that prediction is not supported by all models and makes more assumptions than the basic model makes. Sadly that kind of prediction, which all scientists will admit is controversial and essentially a hypothesis that may or may not come to pass, gets the same attention as predictions, like stratospheric cooling and ice sheet thickening, that have already come to pass.

I hope this helps.