Best not to pay too much attention to the hard core environmentalists or to those who claim definitively that it is not happening. I disagree that skeptics are labelled in that way. I definitely count myself as a skeptic in the sense that it does not appear to me that the case has been proven, but given the potential consequences I think that it is wise to fund further research, explore alternative energy sources, and at least consider the cost/benefit of reducing greenhouse gas emissions.
One concern I have is the activities of certain devloping nations with regards to emissions. Do we really think that China and India and some other rapidly industrializing countries are going to conform and honestly report emissions? I mean, even if the US were to completely eliminate all carbon emissions, isn't the likelyhood that this is going to do little good since China has such a massive and growing industrial footprint? It just seems futile for us to wreck our own economy in many regards if China is going to more than make up for any benefits that we would contribute.