"I don't see what all those environmentalists are worried about," sneers your Great Uncle Joe. "Carbon dioxide is harmless, and great for plants!"
Okay. Take a deep breath. If you're not careful, comments like this can result in dinner-table screaming matches. Luckily, we have a secret weapon: A flowchart that will help you calmly slay even the most outlandish and annoying of climate-denying arguments: