Hey Jack. Toss this at them:
1. Define the correct temperature range for the planet.
2. Define the correct humidity range for the planet.
3. Define the correct mean sea level for the planet
4. Define the correct amount of precipitation for the planet.
5. Define the correct makeup of the atmosphere.
6. Define the correct amount of sea ice at the N/S poles.
7. Define/explain past glaciation and subsequent warming without any input from humans.
That should cause cranial overload/overpressure.
Those are all great questions. Can’t wait to use them on the next AGW believer!