"Why am I still a skeptic?"

"Now, I have accepted the two basic premises of the Global Warming movement — the two points on which the so-called '97% agree' (so count me among them). I have accepted the lines of evidence that the IPCC offers in support of their hypothesis ('It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred' and 'It is very likely that well-mixed GHGs were the main driver of tropospheric warming since 1979…') I have even agreed that CO2 is a greenhouse gas and that it is at an historic high.
    "Why am I still a skeptic?
    "I am still a skeptic because all of those things, freely accepted more-or-less as claimed, do not add up to anything even near a 'proof' of the IPCC hypothesis [that] CO2 and other anthropogenic emissions are 'the dominant cause of the observed warming since the mid-20th century'....
    "I would even go as far as to say that the evidence offered up by the IPCC, in their hundreds of pages of painstakingly reviewed and re-reviewed reports does nothing more than present a case for the possibility that the hypothesis could be true.
    "The IPCC and the Climate Science community have, so far, failed to rule out the CO2 driven global warming hypothesis — nothing more. They have, however, shown in their historical reconstructions that the main bodies of evidence their hypothesis relies on — surface air temperature, sea level rise, snow and ice cover — all started changing long before CO2 concentrations could possibly had any appreciable effect.
    "It is an accepted tenet of modern science that an Effect cannot precede its Cause. So here I find myself accepting the major offered data as more-or-less valid (close enough for my purposes) and the evidences offered as more-or-less true, yet I find that proposed CO2-driven Global Warming Hypothesis, in order to be true, would require retrocausality, or, in other words, that the Effects have preceded the Cause.
    "I am a firm proponent of the idea that time flows in one direction only and that the arrow of cause always points forward (past-to-present, present-to-future). That leaves me forced to reject the CO2-driven Global Warming Hypothesis as generally presented."

~ Science research journalist and contributing expert on sea-level and sea-level rise Kip Hansen, from his post 'Why I Don't Deny: Confessions of a Climate Skeptic, Part 2' (Part 1 is here)