ignoratio elenchi n.
A logical fallacy of presenting an argument that may in itself be valid, but has nothing to do with the proposition it purports to prove. Also known as “irrelevant conclusion”. [Lat. ignorance of refutation.]
George Will is at it again with his OpEd piece "Fuzzy Climate Math" in yesterday’s Washington Post. He makes a lot of pronouncements about global warming, and gets it all wrong. Although I already gave Richard Lindzen an Ignoratio Elenchi Award this week, Mr. Will’s piece is too deserving to go unrewarded.