With the Scientific Method, all new theories must start as a hypothesis. Unfortunately, the SM was discredited on social media as a tool of the imperialist oil stooges. The social media experts (failed English Majors) just declared a 'Truth'.
This fundamental truth stated that carbon dioxide acted as an insulator in the atmosphere because it absorbed a tiny notch of infrared radiation. This built on their declaration that all heat energy on the Earth radiated out as infrared right from the surface. As long as you 'believed' that, then endless projections followed, which all showed we were going to die.
If, for some reason, you wished to follow the SM, then the hypothesis would be stated as "The presence of carbon dioxide interferes with the infrared coming from the surface of the earth. As such, it acts as an insulator, or a thermal blanket. The global temperatures rise uniformly as the concentration of carbon dioxide increases." All aspects of this hypothesis could be tested, but it has been stated in books that this is a 'failed hypothesis'.
In order to create this 'religion' of warming death, they have followed the method of Aristotle. Let's say you have a pot of hot water on the stove with a glass lid. The water is roiling with convection, bringing heat energy from the bottom to the top. Aristotle would look at the pot, and see that the only way heat energy is released is through infrared radiation. His logical inference would be that the infrared started at the bottom of the pot and radiated through the lid into the surrounding space. He would then extend it that adding a bit of soup powder (infrared absorption) would interfere with the radiation and make the water warmer.
Of course, adding a bit of ink or soup to the water makes no difference. The heat is still carried by convection. It's the same with the Earth. All heat is carried through the atmosphere by convection, and radiated at the top into outer space.