He's avoiding knowing because he is aware the scientific consensus is that Climate Change is very real. Acknowledging this would mean he would have to question some cherished beliefs that he is uncomfortable confronting. Notice his wording, "global warming, or climate change, or however they're branding it now." He's dismissive of the idea, not just undecided. He also writes ""I don't know" can be a very bad answer when it is disingenuous." without realizing he's being disingenuous through his entire missive. Being skeptical of Climate Change is like being skeptical that Agent Orange poses a health risk or smoking causes cancer. You can always find a few scientists who hold unfounded beliefs if that is your goal. That isn't healthy skepticism, it's crackpottery. He hasn't spent a lifetime studying cancer but I bet he believes smoking causes cancer. Maybe not? It was Sharon Begley's blog where she points out that Penn and Teller are both supporters of the Cato Institute which disseminates quite a bit of Climate Change denial BS.
John Thornton