Now, I'm not a climate scientist, but I am a physicist, and a former theoretical type who has become sort of Swiss Army Knife kind of generalist. I'm also religious, specifically Christian. With these two attributes in my background, I have these observations to make.
First of all, the climate is changing. It has always changed, and it always will will. See The Long Summer: How Climate Changed Civilization, by Brian Fagan. Briefly, the world has been getting warmer ever since the last Ice Age ended some 12,000 years ago. This warming has been punctuated by some impressive cold (and dry) snaps, one of which turned the former Fertile Crescent into a desert. But the long-term trend has been ever upward. The short name for this is "good weather," as it has contributed to the development of agriculture and with it the origin and growth of complex civilization.
Second, atmospheric carbon dioxide has been a lagging indicator in all the previous upticks in global warming. As the world warms, CO2 is outgassed from the oceans and the tundra, possibly forming a positive feedback loop which strengthens the warming trend. If the current increase in CO2 is a leading indicator, it will be the first time. On the other hand, this could indeed be the case, because a significant fraction of the CO2 has been injected into the atmosphere by humans burning fossilized carbon. We know this, because we can do carbon-14 radioisotopic dating of the carbon in atmospheric CO2.
Third, we now have coupled Ocean-Atmosphere General Circulation Models (OAGCMs) that, together with their component models for clouds, dust, natural biological effects, etc., mimic the long term historical climate pattern pretty well, and produce predictions that are more-or-less consistent with one another, and look like Earth, not Mars or Venus. That is to say, modern climate predictions are no longer based on how quickly or slowly the climate models diverge from what looks like Earth. The predictions are reasonable, but noisy.
Fourth, the noise. One major source of noise is the ENSO, or El Niño Southern Oscillation in the Pacific Ocean, which is dumping so much rain on the US right now. The uptick, El Niño, actually temporarily warms the entire globe a bit. Conversely, the downtick, La Niña, cools it a bit. So, you have to look for trends in noisy data, and match them to trends in noisy predictions. It's a little tricky, especially if you don't have a deep understanding of the statistical techniques available. And even for decent scientists, it's easy to make a mistake and draw a wrong conclusion. This is what some of the critics of the IGPP have done. As they say, "Mistakes were made," on both sides of the climate debate.
Fifth, the ersatz religion. As G. K. Chesterton said,
When people stop believing in God, they don’t believe in nothing — they believe in anything.
Here I think Barone is on point. AGW has become a matter of perverted faith for some people, and therefore, they become disinclined to scrutinize anything that supports their agenda. They are willing to pass on whatever sounds like it agrees with them, in order to stir the people to repentance and reform before Nature visits catastrophe upon them. But stating something as fact without checking it out is what Harry Frankfurt calls bullshit. And it does real damage to the study of climate change, its causes, its effects, and what we can do about it, because it obscures the real science that has been and is being done.
Sixth, what to do about it. The AGW religionists want to put clamps on the global capitalism by Cap and Trade policies that would create markets in carbon emissions offsets. There are precedents for this other than the sale of Indulgences by the pre-Reformation Church. All governments sell or lease the Radio-Frequency RF Spectrum to broadcasters and telecom companies, for example. But the goal of Cap and Trade is to force (not foster) innovation to generate energy in other ways than burning fossil fuels.
We could skip the whip of Cap and Trade, and jump to its goal: innovation. We could try to figure out how to foster innovation to develop and investment to implement alternative energy technologies. Under Cap and Trade, we will have to do that anyway, but why not cut to the chase, and skip the bad economic consequences? After all, we have another incentive to stop burning fossil fuel: most of the world's known remaining petroleum reserves are under control of petro-dictatorships that are ultimately hostile to the peace of the whole world, not just that of the United States. Given that there are real and credible indications that anthropogenic carbon emissions may be accelerating global warming faster than humans can accomodate without an increase in warfare (and we don't need that, do we?) developing alternatives (including nuclear energy) to carbon burning energy is the prudent thing to do.
Finally, there is real religion, and its temptations. In order to guard against idolatrous faith, one must embrace doubt of one's own opinions no matter how cherished. That is why I'm reading the latest volume of Fr. John P. Meier's A Marginal Jew: Re-thinking the Historical Jesus. Look for me to expand my review of the first three volumes when I'm done.
Note Added: See climatologist John R. Cristy's view of the climategate scandal at the University of East Anglia.