Correction to what I say at 7 mins 13: The major reason air pressure decreases is that the gravitational pressure from the air above it decreases. The gravitational force itself also decreases but that’s a rather minor contribution. Sorry about that, a rather stupid brain-fart. How does the greenhouse effect work?
Greenhouse gases, such as carbon dioxide and methane, prevent infrared radiation from escaping to outer space. This warms the surface of earth. More greenhouse gas means more warming. Simple enough! Alas, if you look at the numbers, it turns out that most infrared radiation is absorbed almost immediately above the ground already at pre-industrial greenhouse gas levels. So how does it really work? In this video, I try to sort it out.