Originally posted by Snrrub
This one actually has a very strong theoretical and experimental support. The heat-trapping effect of carbon dioxide (and other gases) is undeniable.

In my opinion it is actually your '2b' point that is suspicious.
True: "and other gases". Any time you look at the actual science behind it, other gases such as sulphur dioxide (a major product of volcanic activity) have at least as much influence; but whenever the environmental lobby starts bellyaching, it's always "carbon emissions" (the "dioxide" bit is always assumed, although I suppose the constant references to "carbon" explain why CO2 is depicted in black balloons - though why they rise into the air is anyone's guess). I suppose I should have said something along the lines of carbon dioxide in the atmosphere being a/the major cause of climate change, but in any case, it comes to the same thing. There is some scientific evidence to support a part of the concept, but definitely not all of it. (Equally with 2b. Humans can definitely affect the amount of CO2 in the atmosphere; every time we exhale, we emit it. Does that have any significant effect?)