One easy way to tell a deny from a realist is how they describe the same simple but very important fact. Carbon dioxide makes up a very small proportion of the Earth's atmosphere. Realists will talk in parts per million, 280, 390, 560. Meanwhile, denialists keen to spread the impression that carbon dioxide is irrelevant, choose to describe it as a percentage, currently 0.038. The subtext is that climate change can't be happening because how could such a small amount of the substance have the sort of effects scientists are warning about. This is a crucial act of intellectual dishonesty because the denialists are comparing apples and oranges. Most of the atmosphere is made up of nitrogen and oxygen. These do not trap heat. If it weren't for that very small amount of carbon dioxide, the temperature on Earth would be well-blow zero and there'd be no life on the Earth's surface. This is basic physics, well-known and understood and accepted since the middle of the 19th century. The denialists know this but they are trying to spread doubt and confusion. So ask them if they accept that carbon dioxide is a greenhouse gas and that nitrogen and oxygen aren't. Ask them if they'd be happy to breathe from a scuba tank with 0.038% of cyanide. Ask them if they would be happy for their children to be driven around by a taxi driver with only 0.01% blood alcohol levels. Hypotism is how science advances, the whole paradigms and falsifiability and epistemic regimes thing is another video. Denialism is about sticking your fingers in your ears and shouting la la la very loudly. It doesn't help anything to allow denialists to pretend to anyone including themselves that they are skeptics.