The copyright police may get TWW but this is important

"Bear in mind that the representation of clouds in climate models (and of water vapour, which is intimately involved with cloud formation) is such as to amplify the forecast warming from increasing atmospheric carbon dioxide—on average over most of the models—by a factor of about three. In other words, two-thirds of the forecast rise in temperature derives from this particular model characteristic. Despite what the models are telling us—and perhaps because it is models that are telling us—no scientist close to the problem and in his right mind, when asked the specific question, would say that he is 95 per cent sure that the effect of clouds is to amplify rather than to reduce the warming effect of increasing carbon dioxide. If he is not sure that clouds amplify global warming, he cannot be sure that most of the global warming is a result of increasing carbon dioxide."

see:  http://quadrant.org.au/magazine/2014/01-02/fundamental-uncertainties-climate-change/