It’s interesting that a couple of replies to my initial comment seem to assume I have accepted the global warming scientific conventional wisdom. I have not! On the contrary, I am extremely skeptical about the methods of the works mentioned above, for the same reasons to which Pierre alludes… lack of world-wide data, especially from the 19th century, urban heat island effects, etc. And yes, the anthropogenic component is not established at all, in my opinion. My point was that global warming “proponents” are using the “you don’t have a climate PhD so you don’t understand and should shut up” argument to silence debate. I have read the major papers. There is very little science there. It’s mostly retrospective statistical analyses of weather station data. It’s not thermodynamics, it’s not statistical mechanics, it’s not physics at all. You don’t need an advanced or specialized degree to understand it and form a defensible opinion.