Why resign if not guilty?
Well let me see...
He might have felt he had proved all that was necessary and wanted to do something else with his life.
He might have felt it wasn't worth being thrown into the limelight as a deciever and resigned in indignation.
He might have got a more lucrative offer to do something else.
He might have wanted to spend more time with his family.
I could go on with possibilities but it's just speculation, just like your belief that he resigned in disgrace. Speculation proves nothing.
What I find interesting about this topic is that whether Global Warming is real or not, whether it's Man's fault or not seems rather irrelevent. The fact of the matter is there are climate changes taking place, weather patterns are changing and polar ice is melting at much faster then expected rates. These things are not in dispute, just what is causing them is being disputed. Cap and trade isn't going to fix it and nothing anyone is doing now is going to fix it because not enough nations are doing enough. What people really need to be focusing on is what are they going to do in response to the effects of this very real climate change regardless of whether it's man made or part of a natural cycle?