Latest Mostly False Fact-checks on Don Zimmerman Don Zimmerman stated on April 27, 2015 in an Austin City Council briefing: "You don't have to be as smart as a fifth-grader to know what causes the climate is the sun. The sun. I have people tell me, ‘Carbon dioxide warms the Earth.’ No, it doesn't. The sun warms the Earth." Don Zimmerman stated on May 31, 2011 in a press release.: "Every time you buy an airline ticket, the federal government runs a background check on you."