It's pretty silly to cast doubt one the crowd who are arguing that global warming is an issue by talking about following the money. Let's put the amount of money that flows from the existing status quo of our fossil fuel based economy vs that amount of money that might be made by those trying to argue that global warming is an issue. I think that even if you were be incredibly generous it would be something approaching an elephant on one side of the scales and a gnat on the other. So if vested interest is a cause for doubting of the ethics and motivations of anyone, it would be vastly disproportionately pointing in the other direction.