The concern stems from the elegant simplicity of the AGW theory. We know that GHGs trap heat, we know that CO2 is a powerful GHG, we know that trophosperic CO2 is up by 40%since the industrial revolution, and there is strong evidence of a decadal scale rise in temperature since the 1870s. Taken in a vacuum, that is awful compelling. But, of course, that vacuum is a myth. To my list of unknowns above, add water vapor, urban heat island, solar cycles, limits (and worse) with climate models, and the possible benefits of some warming.
Yes, the list of anomalies is endless, as are the audacity and unreliability of climate models.
Hey thanks for your time, see you always at FR!