I've seen denials on several counts. That climate change is occurring, that it's anthropogenic, and that the mechanism is CO2 (and other greenhouse gasses released on account of human activities). Much of that confusion being sown by direct and deliberate disinformation campaigns by carbon-aligned interests.

The evidence to my mind is rather incontrovertible in favor of significant anthropogenic climate change.

"climate change" here is a shorthand for "climate change caused by human emissions of CO2". I don't think the OP meant that people deny that the climate changes over time due to natural causes (actually, I think it's incredibly obvious).

I have learned, though, that in a politically charged atmosphere, it is important to be very exact in choosing your words, because people are looking for opportunities to attack.

I'm still surprised by how few people have declared themselves climate change agnosts. That might be because of that course in modeling dynamic systems I took in university though.

As far as I'm concerned we have no way at all of knowing whether we can easily produce orders of magnitude more CO2 without having any significant effect, or whether we're already well beyond the point of no return for life on earth.