I've seen the full-court denial:
- it's not warming, or not significantly
- if it's warming, it's not because of humans, (or)
- if it's warming, it's beneficial
- if it's warming because of humans and that's bad, there's nothing we can do about it
ETA: honorary mention for "what about China?"
People I've argued about this with will switch interchangeably between these. Press them hard enough on one issue, and they'll just switch to another. It's a game of whack-a-mole.
Or "Why does 2 degrees matter?"
Because when were 4 degrees cooler, NYC was under 1000 feet of ice. We really don't want to find out what 4 degrees hotter is like.
Wait really? 1000 feet is insane.
It was actually about 2000 feet. The Laurentide ice sheet, it was 3 kilometers / ten thousand feet thick in some parts.
Same here. I'd also add "It's warming, caused by humans, harmful, but mitigating it would be even more harmful."
Basically, anyone capable of thinking about it logically has at this point reached the conclusion that it's real. Anyone arguing otherwise is therefore necessarily not thinking about it logically, and you have to expect things like shifting claims.