4:50 When you get into high school you'll understand the idea of saturation better. This is how my Falls Church, VA high school George C. Marshall of the late 1970s taught of earth's greenhouse effect. Earth's greenhouse effect is the model of a system always in saturation from the strong greenhouse gas water vapor that adds 10°F (5.55°C) to the earth's average temperature and takes place within 20 meters of the surface, typically the earth. After 20 meters from the radiating surface all the greenhouse radiant energy has been completely absorbed by greenhouse gases. Its further heat transfer is by convection i.e. gas molecules bumping into each other. At 1% average tropospheric water vapor over 99% of earth's greenhouse effect is from water vapor. This is a short and definitive description of the greenhouse effect. It is impossible to make a system in saturation such as earth's greenhouse effect have further effect by increasing its active elements. Global warming cannot be due to greenhouse gases because the only system they are active in is already in saturation from the strong greenhouse gas water vapor. If earth's greenhouse effect were not in saturation then there would be huge changes in the greenhouse effect temperature retention all over the world based on how much humidity was in the air. This would be extremely exaggerated if it were true, which it is not, that some organizations cite as 33°C of average increased temperature for the greenhouse effect, where the scientific recognized average is 5.55°C. At 1% tropospheric average water vapor and 0.04% CO2: (1.00% water vapor) / (0.04% carbon dioxide) = 25 times more concentration of water vapor than than carbon dioxide. Water vapor CO2e=18 X 25 ---> 450 times more temperature forcing for water vapor than carbon dioxide. Even if earth's greenhouse effect were not in saturation CO2 would have no significant effect in it.