claim: In other words, there is as yet no incontrovertible  proof either of the greenhouse effect, or its connection with alleged  global warming.
evidence: Hansen testified that Global warming has reached a level such that we can ascribe with a high degree of confidence a cause and effect relationship between the greenhouse effect and observed warming...It is already happening now and The greenhouse effect has been detected and it is changing our climate now...We already reached the point where the greenhouse effect is important.