I love this false honesty. "But let's be honest" and then the IBD guy goes on to say that he doesn't grant that the climate models are correct.
Of course they're not exactly correct. Only several extra earths, each the same except for CO2 levels, could decisively and perfectly answer the question of what would happen with various CO2 levels.
But we build airplanes based on models, and they may get battery problems but they fly. We build nuclear bombs based on models, and we're so confident in them we don't even test them. And this is nothing new; the first uranium bomb built was used on Hiroshima. There was no test of that design ahead of time.
The climate models are doing much better at the crystal ball game than the deniers.