post the pie graph showing the composition of the atmosphere. its a good reality check.
Whenever someone will listen, I describe the Laurentide Ice Sheet, and just how far the massive ice spreads down from Canada during the very cold, freezing times of the current, real climate. We have short (in geologic time) periods of warming. Sometimes I just start with the fact that Chicago and New York were under a mile of ice, and will be again. I explain that we cannot stop the coming cold times. All we can do is adapt, as humans always have.
I had a sign at my desk: Large Carbon Footprints Make For Happy Trees. I strategically placed it so people would see it. If, after they recovered from the ‘shock’ of such a statement, they would actually listen, I describe the Laurentide ice sheet. I also describe the Natural Carbon Cycle, that those happy trees and plants thrive on C02. Over years of careful, calm conversation, some of those liberals actually began to think, instead of just feel.