Rush said “What warming...caused the ice age to end??”
Technically we are still in an ice age now. We are simply in a interglacial period within this current ice age. When this ice age ends, it will get much, much warmer.
Another glacial period is much more likely though...
I just ask them if they have ever been to Yosemite. Most have and then I ask them how the valley was formed. Most know but if they don’t I inform then. Then I ask, so what happened to the glacier? This usually stops them right there. Unbelievably, many if not most people believe the climate has been stable thoughout the history of the earth and is only changing now because of AGW.